Technology – pv magazine USA

In case you missed it: Five big solar stories in the news this week

pv magazine — Fri, 28 Jun 2024 22:00:30 +0000

pv magazine USA spotlights news of the past week including market trends, project updates, policy changes and more.

Dissecting a $600,000 tax credit transfer In the past, even the smallest projects that attracted tax equity investors required $1 to $2 million in tax benefits to offset the $75,000 in fees. That landscape is now evolving.

1.2 MW Gainesville, Florida solar farm.

Image: Basis Climate

Top solar panel brands in reliability, quality, and performance Solar modules are evaluated in the Renewable Energy Test Center annual PV Module Index. Overall top performers (in alphabetical order): Astronergy, ES Foundry, Gstar, JA Solar, Longi Solar, Runergy, SolarSpace, Trina Solar, and Yingli Solar.

Maine may design a distribution system operator to advance distributed energy resources The Pine Tree State has hired a consulting firm to evaluate whether forming a distribution system operator could speed deployment of distributed energy resources and support other state goals. Consultants are reviewing how the approach is used in five other countries.

City of Detroit to install solar in mostly vacant neighborhoods Three Detroit neighborhoods were chosen as sites for solar facilities. The City plans to build 33 MW of solar to power its municipal buildings.

See where solar manufacturing is planned in North America on Sinovoltaics’ Supply Chain map The up-to-date map provides details on 95 factories producing PV modules, cells, wafers, ingots, polysilicon, and metallurgical-grade silicon in Mexico, Canada, and the United States, up from 81 in the first quarter.

Sunrise brief: New platform vets residential solar salespeople

pv magazine — Tue, 25 Jun 2024 12:00:05 +0000

Also on the rise: Siting solar projects for best environmental results. Top solar panel brands in reliability, quality, and performance. And more.

Maine may design a distribution system operator to advance distributed energy resources Maine has hired a consulting firm to evaluate whether forming a distribution system operator could speed deployment of distributed energy resources and support other state goals. Consultants are reviewing how the approach is used in five other countries.

New platform vets residential solar salespeople An industry plagued by deceptive practices is now verifying salespeople via a platform called Recheck.

Summit Ridge to procure 800 MW of Qcells solar panels The recent agreement brings the total to 2 GW of solar modules that the community solar specialist will purchase from Qcells, mostly manufactured in its facility in Georgia.

More solar installations coming to U.S. military bases In a partnership with Duke Energy valued at an estimated $248 million, the U.S. Department of Defense will be the exclusive purchaser of all output generated by two new solar facilities, which will serve five military bases.

Siting solar projects for best environmental results A new white paper from Clearloop identifies key U.S. regions for best carbon displacement impact of new clean energy projects.

Top solar panel brands in reliability, quality, and performance Solar modules are evaluated in the Renewable Energy Test Center annual PV Module Index.

pv magazine interview: ‘In the next year, some of these guys are going to be bankrupt’ At Intersolar in Munich, pv magazine spoke with Jenny Chase, solar analyst at BloombergNEF, about the incredibly low polysilicon prices, massive overcapacity, and increasing consolidation. According to Chase, this year there will be enough polysilicon capacity to produce 1.1 TW of solar modules, but global module demand is expected to reach around 585 GW.

Siting solar projects for best environmental results

Michael Puttré — Mon, 24 Jun 2024 19:46:17 +0000

A new white paper from Clearloop identifies key U.S. regions for best carbon displacement impact of new clean energy projects.

A recent report by Tennessee-based carbon solutions platform Clearloop noted that private companies have contracted for 71 GW of new renewable energy capacity in the U.S. since 2014, which is enough electricity to power nearly 15 million homes. However, the distribution of solar and wind projects tends to cluster regionally, and not only because of the availability of wind and solar resources. State and utility renewable energy policies play a huge role in where new projects are sited.

Clearloop, which is a subsidiary of solar power producer Silicon Ranch, partnered with non-profit emissions data analysis firm WattTime to study how renewable energy projects – and solar in particular – could be sited to produce better environmental and even social outcomes. The resulting white paper, Curing Carbon Blindness, reinforces the important role of private sector action in growing renewable energy in the U.S. while at the same time saying such action can be better focused to achieve decarbonization goals.

By incorporating the principle of “emmissionality,” the report suggests, companies looking to purchase renewable energy credits (RECs) or offset to their carbon footprints should seek to contract with solar and wind projects in regions with the highest percentage of fossil fuel generation.

Under the current structure, all RECs are essentially created equal, meaning an offtaker in one part of the country can buy RECs from a project anywhere else. There are differences in regional markets, such as ERCOT, but this is generally how it works. Laura Zapata, co-founder and CEO of Clearloop and one of the authors of the carbon blindness report, said not all MWh of clean energy are created equal in terms of their environmental impact.

“We still get over 60% of our electricity in this country from fossil fuels,” Zapata told pv magazine USA. “And so, our goal is how do we build more solar projects in the most carbon intense communities, which also happen to be often the most underserved and disadvantaged communities.”

Unlike most countries, the U.S. does not have a single national energy grid. It is more like a continent with many regional grids of widely varying emissions characteristics. Some regions, such as California, have grids with high percentages of renewables, while others, such as in the southern Appalachians, have fossil-fuel-heavy generation.

There are great disparities in the percentage of fossil-fuel generation (top) and renewable-energy generation (bottom) across the United States. New solar projects in carbon intensive areas have more beneficial environmental effects.

According to the Clearloop report, turning on a light switch in eastern Kentucky will result in 54% more carbon emissions than turning on a corresponding light in Los Angeles. This same data show that a new solar plant located in eastern Kentucky will reduce emissions by 62% more than the same plant would in Los Angeles.

By combining historical irradiance data with WattTime’s marginal emissions data, Clearloop says it is able to model not only how much electricity a solar project is expected to supply the grid, but also the marginal carbon intensity of the power generation sources it is displacing in that region at specific times.

Zapata argues that the marginal difference in emissions that results when solar generation displaces fossil fuel generation should be a key factor in citing projects. Using WattTime’s emissions analysis methodology, Clearloop had identified the regions of the U.S. where new solar, the report’s main focus, would have the greatest decarbonization impact by reducing a like amount of fossil fuel generation sources.

The analysis also extends to voluntary carbon offset markets that rely on private carbon credit registries, such as Verra or Gold Standard. This enables a company to use the methodology for contracting with solar projects to offset its carbon footprint from activities other than electricity consumption, such as air travel.

“Our clients are not interested in the electricity,” Zapata said. “What they want is credit for the environmental impact of those electrons flowing into the grid. So, whether they count them as RECs or offsets, we’re sort of agnostic.”

Maine may design a distribution system operator to advance distributed energy resources

William Driscoll — Mon, 24 Jun 2024 13:30:30 +0000

Maine has hired a consulting firm to evaluate whether forming a distribution system operator could speed deployment of distributed energy resources and support other state goals. Consultants are reviewing how the approach is used in five other countries.

Maine has hired the consulting firm Strategen to evaluate whether a distribution system operator (DSO) could be designed to achieve growth in distributed energy resources and help the state meet other goals: lower electricity costs, improved electric system reliability, and the state’s overall climate goals.

The state law calling for the study defines roles for a DSO including overseeing integrated system planning, operating the state’s electric grids, and administering a market for distributed energy resources (DERs).

Speaking on a webinar about the study, Strategen Advisor Matthew McDonnell said the firm will evaluate the potential to reduce customers’ electric bills by first considering the “base case” for the state of Maine—that is, investment priorities that have already been established through integrated resource planning or other means. The firm will then “look at how a differentiation from that base case to more of a high DER state, as facilitated by a prospective DSO, can enable some potential cost savings going forward through load flexibility and other opportunities.”

Responding to a question about distributed storage, McDonnell added “certainly we’re thinking about distributed energy storage and its use either as a standalone asset or in conjunction with distributed solar or other energy resources.”

Standalone distributed solar was not mentioned on the webinar, which was hosted by the Maine Governor’s energy office.

The energy office said in a statement that no jurisdiction in the U.S. now has a DSO. McDonnell said Strategen is “looking to draw learnings” from similar distribution network operator approaches used in parts of the United Kingdom, Australia, Germany, France, and Ontario, Canada.

If Strategen’s initial study concludes that a DSO can be designed to help achieve the state’s objectives, and the Governor’s energy office agrees with that conclusion, Strategen will conduct a second part of the study to develop a DSO design proposal that identifies the scope and characteristics of a DSO.

A DSO design “may not include the acquisition or ownership of any transmission and distribution utility assets,” the state law says. The law calls on the Maine governor’s energy office to ensure opportunities for stakeholder engagement throughout the study process.

The Strategen team includes consultants Lorenzo Kristov, who previously worked for California’s grid operator CAISO, and Mark Patterson, principal at Energy Catalyst in Australia.

Strategen expects the draft of its initial study to be released in late summer. If a second part of the study is authorized, that part is expected to be completed by year-end.

The nonprofit Clean Coalition, based in California, has advocated for the formation of distribution system operators in that state.

Sunrise brief: Nextracker acquires solar foundation specialist Ojjo for $119 million

pv magazine — Fri, 21 Jun 2024 11:45:19 +0000

Also on the rise: Arizona’s largest energy storage project closes $513 million in financing. Aiko presents ABC solar module with world record efficiency of 25.2% at Intersolar. And more.

Aiko presents ABC solar module with world record efficiency of 25.2% at Intersolar The Chinese back contact module maker said its new products rely on the company’s all-back-contact (ABC) cell technology and feature a temperature coefficient of -0.26% per C.

People on the move: Amp Energy, Deriva Energy, Atwell LLC, and more Job moves in solar, storage, cleantech, utilities and energy transition finance.

Arizona’s largest energy storage project closes $513 million in financing The 1,200 MWh Papago Storage project will dispatch enough power to serve 244,000 homes for four hours a day with the e-Storage SolBank high-cycle lithium-ferro-phosphate battery energy storage solution.

Scientists develop silver-free PEDOT:PSS adhesive for shingled solar cells Researchers from the University of California, San Diego (UCSD) have developed a new silver-free adhesive for shingled solar cells. The novel adhesive is based the PEDOT:PSS polymer and can reportedly reduce silver consumption to approximately 6.3 mg/W.

Longi launches ultra-black HPBC solar modules for residential applications The Chinese manufacturer said its new Hi-MO X6 Artist series has an efficiency of up to 22.3% and a power output ranging from 420 W to 430 W. The smaller version is currently priced at CNY 298 ($41.7)/m2 and the largest model is sold at CNY 268/m2.

Nextracker acquires solar foundation specialist Ojjo for $119 million Ojjo makes a unique truss system that reportedly uses half the steel of a conventional foundation and a design that minimizes grading requirements.

Scientists develop silver-free PEDOT:PSS adhesive for shingled solar cells

Blathnaid O'Dea — Thu, 20 Jun 2024 14:30:56 +0000

Researchers from the University of California, San Diego (UCSD) have developed a new silver-free adhesive for shingled solar cells. The novel adhesive is based the PEDOT:PSS polymer and can reportedly reduce silver consumption to approximately 6.3 mg/W.

From pv magazine Global

A group of scientists from the University of California, San Diego (UCSD) demonstrated that conjugated polymers, which are a class of electronically conductive plastic materials, can be used as an intrinsically conductive adhesive (ICA) to shingled solar cells together.

“This is a new application for a unique class of plastic materials that we are very excited about,” the research’s corresponding author, Alexander Chen, told pv magazine. “While this research is still in its infancy, one exciting aspect about this work is the deep literature and diverse chemistry that can be integrated into conjugated polymers for the purpose of making new types of conductive interconnects and adhesives.”

Shingled solar panels feature a busbar-free structure in which only a small proportion of cells are not exposed to sunlight. The cells are bonded with electrically conductive adhesive to form a shingled high-density string and the resulting strips are connected. The reduced number of busbars reduces shadowing losses.

The shingled cells used in the experiment were built with cell technology supplied by California-based startup Sunpreme and intrinsically conductive adhesives (ICAs) based on the PEDOT:PSS polymer. The performance of solar cells constructed with ICAs was compared to that of counterparts based in silver-based electrically conductive adhesives (ECAs) and the scientists found the former showed “comparable” electrical properties.

Samples of shingled solar cells Image: University of California, San Diego

Samples of shingled solar cells
Image: University of California, San Diego

“While today’s dominant busbar-based modules require around 15.8 mg/W silver, we calculate that shingling modules with ICAs can reduce silver consumption to approximately 6.3 mg/W, accelerating our position on the silver learning curve by approximately two decades. These findings suggest that the design of pi-conjugated materials for ICAs could offer a realistic strategy for sustainable deployment of lower-cost, high-power solar modules,” the paper said.

Even with the removal of silver filler, the researchers achieved similar fill factors (FFs) and overall power conversion efficiency with shingled interconnects. “Employing a conducting polymer as the ICA additionally opens a myriad of opportunities for tuning the electronic, mechanical, and adhesive properties for designing next-generation electronic interconnects,” they added.

There are improvements to be made for the research to be applied further, as the researchers acknowledged in a statement to pv magazine. However, they are optimistic these can be made.

“While we found that the adhesion needs to be improved to reach that of commercial products, we are optimistic that designing better conjugated polymers for applications as intrinsically conductive adhesives can be achieved relatively quickly,” Chen stressed. “This area of research builds upon the incredible wealth of knowledge that already exists on tailoring the electrical properties of conducting polymers and the adhesive properties of traditional polymers. There is a large synthetic space that can be quickly explored here.”

A shingled solar cell

The researchers said they collaborated with a PV engineering services company – D2Solar, Inc. – to integrate the proof-of-concept shingles. “We look forward to working with PV manufacturers to test the concept at larger scales and in relevant outdoor environments,” they added.

The ICAs were presented in the paper “Silver-free intrinsically conductive adhesives for shingled solar cells,” published in Cell Reports Physical Science.

Solar startup claims doubled energy per acre with terrain-following array

Ryan Kennedy — Tue, 18 Jun 2024 17:31:53 +0000

California startup Planted Solar uses construction robots and high-density arrays to deliver what the company says are higher energy outputs and lower balance of system costs.

Planted Solar, a solar startup out of Oakland, California, received $20 million in Series A funding from the Bill Gates Breakthrough Energy Ventures and Khosla Ventures, as well as Department of Energy Funds to scale its terrain-following solar installation design.

The company installs its arrays like a sheet, densely packed together, rather than using typical row spacing. Instead of developing the land to be flat and uniform, the company’s solar mounts follow the terrain, tolerating up to a 27% slope. This helps reduce land development costs and allows for more energy-per-acre.

This may prove important, as the U.S. Bureau of Land Management forecasts the country will need 22 million acres for solar project deployment.

“In comparison to south-facing fixed tilt and tracker designs, a Planted array provides a comparable kWh/kWp yield when using a higher inverter loading ratio (ILR) and is substantially lower in cost of structural balance of system and installation, reduces the amount of civil work and civil risk, and requires a lot less land,” said Planted Solar.

The company said its design allows for a megawatt of solar to be installed on only two acres, less than the five acres typically required for a megawatt of solar capacity. Its simple terrain-following mount leads to a 50% reduction in balance of system costs and fewer installation hours.

“This adds up to a system with a lower build cost, higher DC system size, and similar annual kWh production,” said the company.

The terrain-following mounts are compatible with all conventional module formats and sizes, said the company.

After completing the design phase, the company uses installation robots to deploy the solar panels, which it said reduces installation time and costs. Planted Solar said its design mitigates impacts like erosion on the developed land, which is explained in a whitepaper.

“Planted’s low-impact approach to fixed-tilt solar PV foundation and table installation is novel in its automation, low impact/low disturbance, and tolerance to using existing ground conditions without grading. Furthermore, the low-area cross section of the Planted foundation legs should reduce local scour when compared to traditional pile. Installing using Planted’s methodologies will reduce disturbance and resultant hydrological and hydraulic impact to a site versus traditional installations of solar arrays,” said Planted Solar.

Planted Solar’s design mitigates the need for vegetation removal and erosion.

Planted Solar chief executive officer Eric Brown said it is rapidly “moving from pilots to portfolios.” The company announced it was selected for an 11 MW portfolio of projects in the Chicago area with Cultivate Power.

“Planted Solar gives our team a strategic tool to be stewards of the land and develop better projects with our community partners,” said Brian Matthay, co-founder and managing director of Cultivate Power. “Cultivate is focused on collaborating with landowners and communities so we can integrate solar seamlessly with the local environment and agricultural operations.”

Princeton NuEnergy scores $30 million in funding for lithium battery recycling

Anne Fischer — Mon, 17 Jun 2024 19:11:17 +0000

The low-temperature plasma-assisted separation process, developed at Princeton University and now trademarked as LPAS, produces battery-grade cathode and anode materials suitable for direct reintroduction into cell manufacturing.

Princeton NuEnergy (PNE), a New Jersey-based specialist in lithium-ion battery direct recycling, announced the close a Series A funding round with a strategic investment from Samsung Venture Investment Corporation.

Founded out of Princeton University in 2019, PNE developed a patented direct recycling technology for lithium-ion batteries. The low-temperature plasma-assisted separation process, trademarked as LPAS, produces battery-grade cathode and anode materials suitable for direct reintroduction into cell manufacturing. The company reports that this recycling is done at half the cost and is 70% less energy intensive.

PNE is now commercializing its lithium-ion battery recycling process that the company reports recovers up to 95% of materials found in all lithium-ion battery chemistries.

Recovering lithium and other critical battery materials is important as the U.S. ramps up electric vehicle produciton. While the U.S. is making strides toward manufacturing batteries, it is behind in the race for raw materials as China reportedly holds the majority of the world’s lithium refining capacity.

To advance lithium battery recycling, PNE has received over $55 million in grants, strategic and venture funding including investments from Honda Motor Co. Ltd., LKQ Corporation, Samsung Venture, Shell Venture, Traxys Group, Wistron Corporation, and the U.S. Department of Energy.

Investor demand for this 50% oversubscribed round brought PNE’s Series A total to $30 million. Samsung Venture and Helium-3 join the round’s previous investors. The funds will support construction of PNE’s first standalone, full-scale direct battery recycling advanced manufacturing facility.

“The incredible interest in our Series A round, capped off by a strategic investment from Samsung Venture Investment Corporation and Helium-3 Ventures, speaks to the importance of supporting a circular economy for lithium battery manufacturing here in the U.S.,” said Dr. Chao Yan, PNE’s co-founder and CEO. “This funding enables us to implement and demonstrate our capabilities at commercial scale, helping America meet the growing demand for high-performance batteries while also creating high-quality clean energy jobs.”

PNE was named to Time Magazine’s “America’s Top Greentech Companies 2024”

Longi claims 34.6% efficiency for perovskite-silicon tandem solar cell

Vincent Shaw — Mon, 17 Jun 2024 15:44:07 +0000

The European Solar Test Installation (ESTI) confirmed Longi’s achievement of a world record-breaking efficiency rating of 34.6% for a perovskite-silicon tandem solar cell.

From pv magazine Global

Longi announced at the SNEC tradeshow in Shanghai, China, that it has achieved a power conversion efficiency of 34.6% for a perovskite-silicon tandem solar cell.

The European Solar Test Installation (ESTI) has certified the results, which represent a world record for this cell typology. The previous record was held by Longi itself, which achieved an efficiency of 33.9% in November.

“We achieved this result by optimizing the thin film deposition process of the electron transport layer, developing and using high-efficiency defect passivation materials, and designing and developing high-quality interfacial passivation structures,” the company said in a statement, without providing further details.

In June, Longi reported an efficiency of 33.5% for the same cell. The European Solar Test Installation (ESTI) certified the results, which represented a significant increase on its previous 31.8% efficiency rating, which was announced during last year’s SNEC edition.

Longi has broken the world record for solar cell efficiency 16 times since April 2021. It claimed the world’s highest efficiency for silicon cells in November 2022, with a 26.81% efficiency rating for an unspecified heterojunction solar cell.

Long-duration stability of perovskite solar cells

Patrick Jowett — Mon, 17 Jun 2024 13:53:42 +0000

US scientists have analyzed the impact of “seasoning” a formamidinium lead iodide solution with two-dimensional (2D) perovskites. They have found that the template improved the efficiency and durability of their solar cells.

From pv magazine Global

Scientists from Rice University in Houston, Texas, have improved the stability of pervoskite solar cells by distributing 2D perovskites.

The scientists synthesized formamidinium lead iodide (FAPbI3) into ultrastable, high-quality photovoltaic films for high-efficiency perovskite solar cells. They hypothesized that using more stable 2D perovskites as a template could impart their stability to FAPbI3 during growth.

They fabricated four types of 2D perovskites to test the idea, two closely matching FAPbI3’s surface structure and two less well-matched, and used them to make different FAPbI3 film formulations. They found that the 2D crystal template improved both the efficiency and durability of FAPbI3 solar cells. Solar cells with 2D templates didn’t degrade after 20 days of generating electricity in air, while those without 2D crystals degraded significantly after two days.

“The addition of well-matched 2D crystals made it easier for FAPbI3 crystals to form, while poorly matched 2D crystals actually made it harder to form, validating our hypothesis,” said Isaac Metcalf, the lead author of the study. “FAPbI3 films templated with 2D crystals were higher quality, showing less internal disorder and exhibiting a stronger response to illumination, which translated as higher efficiency.”

The research team then found that by adding an encapsulation layer to the 2D-templated solar cells, stability was further improved to timescales approaching commercial relevance. According to their research paper – “Two-dimensional perovskite templates for durable, efficient formamidinium perovskite solar cells,” recently published in Science – the fabricated cell had a power conversion efficiency of 24.1% for a 0.5-square-centimeter active area and maintained 97% of their efficiency for 1,000 hours at 85 C under maximum power point tracking.

“Right now, we think that this is state of the art in terms of stability,” said Rice University engineer Aditya Mohite, “Perovskite solar cells have the potential to revolutionize energy production, but achieving long-duration stability has been a significant challenge.”

The team said that the findings could have an impact on light-harvesting, reduce manufacturing costs, and enable development of solar panels with that are lighter and more flexible than silicon solar panels.

“Perovskites are soluble in solution, so you can take an ink of a perovskite precursor and spread it across a piece of glass, then heat it up and you have the absorber layer for a solar cell,” Metcalf said. “Since you don’t need very high temperatures – perovskite films can be processed at temperatures below 150 C – in theory, that also means perovskite solar panels can be made on plastic or even flexible substrates, which could further reduce costs.”

Swift Solar closes $27 million in funding, plans perovskite solar factory

Anne Fischer — Thu, 13 Jun 2024 19:42:51 +0000

Swift Solar, a specialist in perovskite tandem photovoltaics, plans to build a factory in the U.S. in the next two to three years to manufacture thin-film solar.

Swift Solar announced the close of its $27 million Series A financing round, which follows on the heels of a $7 million award from the Department of Energy under the Advancing U.S. Thin-Film Solar Photovoltaics funding program.

The company, founded in 2017 is a spinout of MIT, Stanford University and the National Renewable Energy Laboratory (NREL), and specializes in perovskite tandem photovoltaics. The new technology combines metal halide perovskites with silicon or other perovskites to make tandem cells that have higher efficiency than traditional solar cells.

The $27 million funding round was co-led by Eni Next and Fontinalis Partners. Also joining the round are new and existing investors including Stanford University, Good Growth Capital, BlueScopeX, HL Ventures, Toba Capital, Sid Sijbrandij, James Fickel, Adam Winkel, Fred Ehrsam, Jonathan Lin, and Climate Capital.

The $7 million DOE funding is part of a $71 million investment, including $16 million from the Bipartisan Infrastructure Law, which supports research, development and demonstration projects in order to help grow the domestic solar supply chain. Swift Solar was one of four awardees that are working on tandem PV devices that pair established PV technologies like silicon and copper indium gallium diselenide (CIGS) with perovskites.

In total, Swift Solar has raised $44 million to scale its technology as it prepares to break ground on its first manufacturing facility.

“Solar is the future of energy—not just clean energy,” said Joel Jean, co-founder and CEO of Swift Solar. “Our advanced perovskite solar cells can outperform anything currently available on the market.”

A novel vapor deposition technology may help it to accelerate the manufacture of its tandem solution. The new method is a non-batch process that solves two problems associated with the use of established vapor processing in perovskite material manufacturing – the slow speed of deposition and the non-continuous nature of batch processing.

“Our deposition approach allows for the continuous deposition of a fully absorbing perovskite material within less than five minutes,” corresponding author Tobias Abzieher from Swift Solar, a U.S.-based perovskite PV startup, told pv magazine. “Solar cells prepared with these materials also outperform previously realized efficiencies of vapor processed inorganic perovskite solar cells significantly.”

In its announcement, Swift Solar noted that perovskite solar cell production uses less material and less energy, which should drive down manufacturing costs and carbon pollution, potentially decreasing the cost of solar by up to 30%. “The perovskite supply chain could be based entirely in the United States and aligned countries, creating a major opportunity to expand domestic manufacturing,” according to Swift.

Swift Solar’s initial products will be designed for integration in high-performance solar-powered products such as on car rooftops or space-based satellites, and the company says it will also serve traditional solar customers.

Swift Solar was recently named one of TIME’s Top GreenTech Companies in America. In April, The Solar Energy Manufacturers for America (SEMA) Coalition announced the Swift Solar was a new member.

This article was amended to remove mention of company developing rooftop product.

Sunrise brief: Utility-scale solar far less costly than the cheapest fossil fuel source

pv magazine — Wed, 12 Jun 2024 12:00:59 +0000

Also on the rise: Five Puerto Rico reservoirs could host 596 MW of floating solar. Weather-related damage to solar assets exceed modeling expectations by 300%. And more.

Flexible interconnection with curtailed output can benefit everyone, analyst says Allowing flexible interconnection for large solar projects can reduce costs and speed deployment, benefiting developers, ratepayers and utility staff, said a presenter at a North Carolina conference of utility regulators.

Startup launches online platform for residential PV system purchase Two-year old Monalee developed an online platform for homeowners looking to buy solar PV and storage systems. Its software enables the process from quotes to financing, installation and after-sales support.

Concentrator photovoltaic module based on surface mount technology A research group in Canada has optimized the performance of concentrator photovoltaics by using the so-called surface-mount technology for thermal management. The CPV module prototype utilizes four non-interconnected III-V germanium cells, a Fresnel lens, and a transparent glass printed-circuit board.

Five Puerto Rico reservoirs could host 596 MW of floating solar Potential sites for solar in Puerto Rico include reservoirs, brownfields, closed landfills, fossil generating plants after closure, and transmission rights of way, determined analysis by the National Renewable Energy Lab.

Cheapest source of fossil fuel generation is double the cost of utility-scale solar Solar levelized cost of electricity (LCOE) has fallen to $29 to $92 per MWh, said a report from Lazard.

List of top solar module manufacturers led by JA Solar, Trina Solar, Jinko Solar Wood Mackenzie says that JA Solar has taken first place on its list of solar panel manufacturers. Nine of the first 12 positions are held by Chinese manufacturers, seven of them could surpass 100 GW of capacity by 2027, and eight are self-sufficient in cell capacity, according to the research firm.

Largest ground-mount solar project in downtown Washington D.C. now operational The community solar installation at The Catholic University of America was built through a collaborative effort between the university and 1,200 local residents.

Five Puerto Rico reservoirs could host 596 MW of floating solar

William Driscoll — Tue, 11 Jun 2024 15:58:19 +0000

Potential sites for solar in Puerto Rico include reservoirs, brownfields, closed landfills, fossil generating plants after closure, and transmission rights of way, determined analysis by the National Renewable Energy Lab.

The National Renewable Energy Laboratory (NREL) has estimated that five reservoirs in Puerto Rico could host 596 MW of floating solar, although the costs would be about 25% higher than for ground-mounted solar. NREL published its analysis in a report and a technical annex.

The analysis grew out of a concern, NREL said, that “Puerto Rico’s commitment to achieving 100% clean energy by 2050 will require identification of suitable sites for new generation projects.”

An additional 190 MW of “economically viable” solar projects are possible across seven sites designated as “Superfund” sites by the U.S. Environmental Protection Agency (EPA), the study found. For six of the sites, analysts assessed “how much grant money is needed” to meet economic targets for solar projects under municipality-owned and third-party owned models.

Image: Dennis Schroeder, NREL

In comparison to those estimates, both in the hundreds of megawatts, Puerto Rico has the potential for tens of gigawatts of both rooftop and large-scale ground-mounted solar, according to NREL’s “PR 100” summary report published early this year.

Across all residential buildings, Puerto Rico has the “technical potential” for 20.4 GW-dc of rooftop solar, that report estimated. A technical potential analysis does not consider the financial viability of projects. The U.S. territory reached 680 MW of rooftop solar last October.

Puerto Rico’s technical potential for utility-scale solar ranges from 14.2 GW under a “less land” scenario to 44.7 GW under a “more land” scenario, the PR 100 summary report said.

In both scenarios, modeled development of utility-scale solar was “restricted from” roadways, water bodies, protected habitats, flood risk areas, slopes greater than 10%, and agricultural reserves. But in the “less land” scenario, solar was also restricted from areas identified for agricultural use in the Puerto Rico Planning Board’s 2015 Land Use Plan.

NREL’s new analysis also estimated technical potential for 1–2.5 GW of solar across 160 contaminated sites, a total of 636 MW of floating solar on 55 water bodies, 213 MW of solar on 41 closed landfills, 78 MW of solar at two fossil generating plants once they are closed, and 21–50 MW of solar on transmission line rights-of-way.

The new NREL analysis adapted a methodology from an EPA decision tree tool titled “RE-Powering America’s Land Initiative.”

Concentrator photovoltaic module based on surface mount technology

Emiliano Bellini — Tue, 11 Jun 2024 14:13:38 +0000

A research group in Canada has optimized the performance of concentrator photovoltaics by using the so-called surface-mount technology for thermal management. The CPV module prototype utilizes four non-interconnected III-V germanium cells, a Fresnel lens, and a transparent glass printed-circuit board.

From pv magazine Global

Scientists from the Université de Sherbrooke in Canada have fabricated a prototype of a concentrator photovoltaic (CPV) module based on the so-called surface-mount technology (SMT) – a technique that is commonly used to mount electronic components to the surface of a printed circuit board (PCB).

The proposed SMT design used no wire bonding for cell emitter connection and is intended to increase heat dissipation in the CPV panel, which in turn reduces its operating temperature and increases its performance.

“The SMT, which uses a conductive solder paste for interconnection, has the advantage of being less expensive and faster for large-scale production, and SMT equipment takes up less space than wire-based wiring equipment,” they explained. “We have developed and employed the SMT process, which integrates assembly flexibility and enhanced alignment of solar cells, to assemble the solar cells larger than a millimeter in size.”

The 4-solar cell CPV module prototype uses a Fresnel lens to concentrate light onto cells soldered on a transparent glass PCB and protected by lamination layers. The emitter contacts are soldered through conductive solder joints to a glass PCB, which embeds metal tracks for the non-soldered areas. Transparent underfill fills the gap between the solar cell and the PCB to prevent reflections at the interfaces of the module’s bottom plate.

“Underfill fillets protect the sides of the solar cell to prevent short circuits and contribute to the thermomechanical stability of the assembly,” the research team stated. “The back face of the assembly is laminated with an EVA encapsulant and a Tedlar protective sheet to preserve the solar cells from the environment.”

Schematic of the CPV module

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Schematic of the CPV moduleImage: Université de Sherbrooke, Solar Energy Materials and Solar Cells, Common License CC BY 4.0

The four cells used in the device are non-interconnected with each other, and are triple-junction III-V germanium solar cells, each with an active surface area of 8.751 mm². The cost of solar cells based on compounds of III-V element materials, named according to the groups of the periodic table that they belong to, has confined the devices to niche applications, such as drones and satellites. These are applications where low weight and high efficiency are more pressing concerns than costs.

The scientists mounted the 4-cell CPV SMT module on a 2-axis solar tracker from the Helios platform at the University of Sherbrooke.

The group took a series of electrical and temperature measurements on the system under real operating conditions and also conducted a series of simulations based on the finite element model (FEM), which is a numerical technique used to perform finite element analysis (FEA) of physical phenomenon.

Through their analysis and experiments, the academics found that the dimensions of the metal ribbon at the back of each cell and the metal coverage ratio of the PCB are key factors for the thermal management of the CPV module, while the other components have a negligible impact on the module temperature.

“The temperature of the solar cell can be kept below 80 C over a wide range of dimensions of the metal ribbon behind the solar cell, both for a metal coverage of the PCB of 0 % or 100 %,” they further explained. “However, this dimensional range is much wider when the metal coverage ratio is 100 % than when the metal coverage ratio on the PCB is 0 %.” The simulation also showed that the temperature of the solar cells may reach 54 C with a copper ribbon and 57 C with an aluminum ribbon.

The system was described in the paper “Finite element modeling and experimental validation of concentrator photovoltaic module based on surface Mount technology,” published in Solar Energy Materials and Solar Cells. “These results demonstrate that in addition to simplifying the assembly process, using SMT for CPV modules fabrication can enhance heat dissipation both by the metallic layer on the glass PCB and on the back side contact,” the researchers concluded. “This opens the door to simpler CPV modules, higher performance CPV modules and higher concentration ratios.”

Flexible interconnection with curtailed output can benefit everyone, analyst says

William Driscoll — Tue, 11 Jun 2024 13:00:31 +0000

Allowing flexible interconnection for large solar projects can reduce costs and speed deployment, benefiting developers, ratepayers and utility staff, said a presenter at a North Carolina conference of utility regulators.

Duke Energy Progress has announced network upgrade costs of $470 million to interconnect about 1.9 GW of solar and solar-plus-storage projects in North Carolina and South Carolina that were proposed in response to its 2023 resource solicitation, with an average lead time until interconnection of 4.5 years.

A “significant” portion of the identified upgrades could be avoided “with minimal or zero impact to reliability” if a more flexible interconnection service that provided for occasional curtailment of solar generation could be used, said Tyler Norris, a Duke University Ph.D. candidate and former Cypress Creek Renewables executive, at a meeting of the Southeastern Association of Regulatory Utility Commissioners.

Under flexible interconnection, a project would be required to curtail its output when transmission is congested.

Norris said North Carolina does not currently allow flexible interconnection for state-jurisdictional projects. Yet he said flexible interconnection would yield benefits for solar developers, ratepayers, and utility staff.

Speed of interconnection is one benefit. Norris noted that Texas, where the grid operator ERCOT allows a form of flexible interconnection, has quickly added solar in recent years. Although North Carolina ranked second in utility-scale solar deployment in 2019, Texas “sort of blew past us, they blew past Florida, and now they’ve surpassed California as well.”

ERCOT’s approach to flexible interconnection, known as “connect and manage,” suits the grid operator’s energy-only electricity market, Norris has previously written, and could be adapted for use elsewhere in the U.S. where electricity markets have a capacity market alongside an energy market.

Norris said the Duke utility’s expected network upgrade costs for the 1.9 GW of projects follow an approval by the North Carolina Utilities Commission for about $600 million in network upgrades “which was precisely intended to integrate more utility-scale solar and solar-plus-storage.”

North Carolina does not permit flexible interconnection, Norris said. So the utility’s cost study did not consider the “ability to curtail those resources in real time during peaks” as a way to avoid the upgrades. Many large network upgrades that are allocated to projects in interconnection studies “may be triggered due to rare or even extremely rare contingencies,” he said.

“This isn’t to pick on Duke by any means,” he said. “I think they’re doing a great job on a lot of fronts.”

Norris plans to work with team members at Duke University to analyze the network upgrade costs for the 1.9 GW of solar and solar-plus-storage projects under a scenario in which energy-only interconnection was allowed.

Avoiding network upgrade costs through flexible interconnection would ultimately help ratepayers, Norris said. “All these costs end up going to the ratepayers. We assign them to the projects, but either it shows up for the ratepayers in the form of a higher power purchasing agreement (PPA) price, or in the form of going directly into the rate base.”

Flexible interconnection could reduce the burden on a utility too, Norris said. “We already have a lot of other transmission and network upgrades going on for other reasons,” he said, and “layering more and more” upgrades for particular projects puts “more burden on already strained utility construction teams and planning teams.”

More generally, Norris said that “we’ve already invested a huge amount” in the existing transmission network, and that “if we can get more generators on the system that don’t require more and more network upgrades, we’re making more efficient use of that expenditure we’ve already made.”

Norris noted that in the U.S. Department of Energy’s recent interconnection roadmap, “one of the key themes that came out of it was offering fast track and more flexible interconnection options as a priority solution.”

Norris expects that a Federal Energy Regulatory Commission interconnection workshop set for September 10-11 will address issues related to flexible interconnection.

Longi presents 24.4%-efficient 660 W HPBC solar panel

Emiliano Bellini — Mon, 10 Jun 2024 17:45:34 +0000

Intended for applications in utility-scale PV projects, the new Hi-MO 9 module is available in eight versions with power output ranging from 625 W to 660 W and power conversion efficiency spanning from 23.1% to 24.4%.

From pv magazine global

Chinese solar module manufacturer Longi unveiled a new module series based on its proprietary hybrid passivated back contact (HPBC) cell technology.

“Longi’s first-generation BC products were primarily positioned for the rooftop market, but the second generation of BC is entirely different,” the company said in a statement. “The Hi-MO 9 panel is mainly positioned for the ground-mounted utility market.”

The new product is available in eight versions with power output ranging from 625 W to 660 W and power conversion efficiency spanning from 23.1% to 24.4%. The open-circuit voltage is between 53.30 V and 54.00 V and the short-circuit current is between 14.85 A and 15.41 A.

The double-glass modules have a temperature coefficient of -0.28%/C and a maximum system voltage of 1,500. Their size is 2,382 mm x 1,134 mm x 30 mm and their weight is 33.5 kg. They also feature IP68 junction boxes, an anodized aluminum alloy frame, and 2.0 mm coated tempered glass.

The new products come with a 12-year product warranty and a 30-year linear power output warranty, with the 30-year end power output being guaranteed to be no less than 88.85% of the nominal output power.

“In the second-generation BC product, the company has comprehensively optimized the bifaciality issue,” the company said, noting that the bifaciality factor cannot generally be very outstanding in back contact technologies. “However, taking this into full consideration, the overall life-cycle power generation capability we display now an improvement of 6% to 8%,” it added, without providing more details.

The company has not revealed yet all the technical aspects of its HPBC cell technology. It previously said it’s an extension of p-type interdigitated back-contact (IBC) technology that combines the structural advantages of PERC, TOPCon, and IBC solar. Additionally, BC technology can be combined with p-type wafers, for which Longi has substantial production capacities, giving it an advantage over the more common IBC technology.

In March, Longi launched its Hi-MO X6 Explorer and Hi-MO X6 Guardian modules, and last week it introduced the Hi-MO X6 Scientist panel.

Community solar increases energy equity, report finds

Anne Fischer — Mon, 10 Jun 2024 13:30:53 +0000

For the first time research looks at data about households adopting community solar along with policy that promotes outreach, and the results confirm that coalition efforts are beneficial.

Community solar makes solar accessible to those who live in multifamily housing and don’t own their rooftops, can’t afford the upfront cost of solar or whose roofs are not oriented favorably for solar. A recent study by researchers at Lawrence Berkeley National Labs (LBNL) and published in Nature Energy, shows that community solar extends clean energy to communities that would have otherwise struggled to adopt rooftop solar.

“Their findings are compelling: community solar subscribers are 6x more likely to live in multifamily housing and 4x more likely to rent. This reaffirms what we have known to be true for years — community solar is one of the best ways to increase equity in our energy system,” said Molly Knoll, vice president of policy for the Coalition for Community Solar Access (CCSA).

Wood Mackenzie found that the share of community solar serving low-to-moderate income (LMI) subscribers grew from 2% to 10% in just one year, with costs decreasing 30% over the same period. In a report on community solar, Wood Mackenzie expects 7.6 GWdc of new community solar will come online in existing state markets between 2024 and 2028, and the national total of community solar installations are expected to pass 10 GW of cumulative capacity in 2026.

The Wood Mackenzie report noted that residential customers are representing an increasingly larger share of community solar subscriptions, suggesting a shift in focus for developers and providers. Low- and middle-income (LMI) customers rose from 2% of the customer base to 10% from 2022 to 2023, with costs to subscribe these customers declining 30% year-over-year.

Knoll pointed out that the Wood Mackenzie findings along with the LBNL findings, shows that policy that supports community solar adoption by LMI customers cannot only increase solar adoption but can also decrease overall costs.

For the first time, the researchers combine household-level data from Berkeley Lab’s Tracking the Sun rooftop solar adopter data set with data compiled under NREL’s Sharing the Sun community solar research, as well as additional community solar adopter data collected for the study. To determine how well community solar is serving the needs of those who are underserved by the rooftop solar market, the study looked at the demographic characteristics of the two adopter groups.

Based on a sample of 11 states, the LBNL study found that community solar adopters in 2023 were about 6.1 times more likely to live in multifamily buildings than rooftop solar adopters, 4.4 times more likely to rent, and earned 23% less annual income. Based on this, the researchers conclude that community solar has effectively expanded solar access to multifamily housing occupants, renters and low-income households.

The researchers also looked at what drives community solar participation: business models or policy. The business model removes barriers to adoption by allowing households to adopt solar without owning a home or having exclusive access to a rooftop. This is especially appealing to those who live in multifamily buildings and/or who are renters.

On the other hand, the researchers found that policy has helped to provide targeted support to help low-income households adopt community solar.

The conclusion was that business models and policy are equal in influencing community solar.

According to CCSA’s Knoll, this equitable access will increase substantially as more state policies include requirements that projects serve LMI customers. She noted that the $7 billion infusion from the EPA’s Solar for All competition will further speed LMI adoption.

“This study is important confirmation of one of the values community solar can bring to the electric grid and the tireless work our broad and diverse coalitions are doing to bring community solar to every state in the country,” said Knoll.

The authors of the Berkeley Lab study will host a free webinar on June 18^th at 11 a.m. PT/2 p.m. ET.

DOE announces $38 million solar supply chain incubator funding opportunity

Ryan Kennedy — Fri, 07 Jun 2024 14:57:56 +0000

The funds support research, development and demonstration projects that de-risk solar hardware, manufacturing, and software products.

The U.S. Department of Energy announced a $38 million funding opportunity via its Solar Energy Technologies Office (SETO), supporting research, development, and demonstration projects related to the solar energy supply chain.

The funds are intended to support projects that de-risk solar hardware, manufacturing processes, and software products. The funding opportunities also seeks projects that provide outreach, education, or technology development for software that delivers an automated permit review and approval process for rooftop solar and/or energy storage.

“These investments will help accelerate the growth of the solar industry, identify emerging opportunities, and drive down costs for our domestic energy market, positioning the United States on the leading edge of solar industry advances,” said DOE.

Eligible technologies include PV, systems integration, concentrating solar-thermal power, technologies that connect solar with storage or electric vehicles. It also considers dual-use projects like agrivoltaics and vehicle-integrated photovoltaics.

Topic areas:

1. Solar Research and Technology Development

DOE will support five to ten projects receiving $1 million to $2 million each. The topic area focuses on R&D projects for for-profit companies improving and de-risking solar components and/or manufacturing processes. Successful project submissions will develop and validate realistic pathways to commercial success.

2. Solar Energy Demonstration

Five to ten research, development, and demonstration projects will receive between $1 million and $5 million for established companies or startups to develop pilot-scale or prototype demonstration of solar products. Successful applicants for this topic area will have an existing prototype that requires further testing, engineering work, or demonstration in a controlled environment.

3. Solar Permitting, Outreach, Education

One to three projects receive between $1 million to $5 million for outreach, education, and software development activities for automated code-compliant rooftop solar permitting software. The projects are designed for use by solar installers to submit permit applications to local governments and to automate review and approval.

DOE will hold an informational webinar on the funding opportunity on June 13, 2024.

Link to Apply: Apply on EERE Exchange

Zinc-ion batteries: A less volatile alternative?

Sergio Matalucci — Fri, 07 Jun 2024 13:53:56 +0000

At a time of growing demand for battery energy storage, pv magazine spoke with Eloisa de Castro, CEO of Enerpoly, a Swedish company preparing to launch the world’s first zinc-ion battery megafactory on its home turf. Having solved rechargeability issues, the company expects its safe and sustainable zinc-ion batteries, which rely solely on a European supply chain, to increase their market share in the years to come.

From pv magazine ESS News site

The energy storage market was worth between $44 billion and $55 billion in 2023, and it’s predicted to reach up to $150 billion by 2030. However, it faces major economic and supply challenges related to the usage of batteries made with scarce and price-volatile materials. How can your company help address these issues?

Eloisa de Castro: Enerpoly develops and manufactures batteries using zinc and manganese as the active materials. The strategic use of globally available and reusable materials plays a significant role in ensuring a stable and reliable supply chain that is resistant to price volatility and geographical constraints. Our zinc-ion batteries rely 100% on a European supply chain, which reinforces their resilience.

Our batteries are environmentally friendly, cost-effective, and safe, and address various large-scale stationary energy storage requirements, including grid stabilization services or reliable backup power. In essence, the attributes of our batteries allow us to provide scalable, reliable and sustainable energy storage solutions.

Enerpoly’s technology meets the affordability, safety, and sustainability demands that are essential for the clean energy transition. Additionally, our recent grant from the Swedish Energy Agency, which will be used to build the world’s first megafactory for zinc-ion batteries, demonstrates that zinc-ion batteries can be affordably and mass-produced at scale.

How did you solve the rechargeability issues typical of zinc-ion batteries?

Enerpoly implemented several key innovations to address these issues. Our zinc-ion batteries use a zinc metal anode and manganese dioxide cathode. We developed strategies that limit inactive manganese species from forming. This is important because manganese oxide could change phase to electrochemically inactive Mn3O4 and cause battery degradation. This innovation significantly enhances both battery performance and rechargeability.

Second, we had to tackle the problem of zinc dendrite formation on the anode. Zinc dendrites can cause short-circuits. We developed a proprietary electrolyte and a controlled battery operation approach to prevent dendrites. Optimization of the battery as a whole must be considered each time there is an innovation to one component, and we have been careful to balance any potential side reactions that can occur with each new modification.

What would the rise of zinc-ion batteries entail for the supply chain and zinc prices?

Zinc is already used in a variety of industrial applications, so an increase in the demand of zinc batteries is unlikely to result in major price fluctuations. Zinc-ion batteries are better insulated from supply chain issues and inflation that have impacted the energy space in recent years. If you look at the zinc prices compared to lithium prices in 2022 and 2023 when commodity prices were the most volatile, lithium had a 14x price volatility and zinc had around 1x.

In addition to that, I expect that the existing recycling of zinc and the extraction of zinc from other important industrial applications creates a more circular supply chain and makes the sourcing flexible, therefore keeping the price quite low and stable. Enerpoly’s focus on zinc, a more stable and less geopolitically constrained material, positions us to appropriately manage any potential cost instability even as demand rises.

How viable is mining and refining of zinc?

Here’s what is in zinc’s favor: zinc is responsibly and sustainably mined in Europe, and there is 200 times more mining capacity for zinc than there is for lithium in Europe. As for the refined battery-grade materials, Enerpoly uses similar materials as in non-rechargeable zinc-alkaline batteries, and the refining and manufacturing of zinc for European battery manufacturing has been done successfully and reliably for decades by the suppliers of existing European battery giants for the non-rechargeable version of this battery. I cannot say for certain that we will never run into issues, but I have confidence that the chance of coming across major obstacles is very, very low.

Apart from supply chain issues, lithium-ion batteries also carry significant safety risks and face sustainability challenges in their manufacturing and recycling processes. How are zinc-ion batteries different?

Enerpoly’s zinc-ion batteries use no components that can cause thermal runaway, and our zinc-ion batteries, unlike other battery chemistries, are not classified as dangerous goods and are therefore safe for transportation and storage. Some potential positive effects of increased safety include further reduced cost because there is no need for specialized fire suppression components and lower insurance costs, and the ability to deploy in safety-critical applications as well as dense urban areas without the risk of explosions.

Enerpoly’s batteries also use state-of-the-art dry electrode manufacturing and they do not require dry rooms or toxic solvents in production, all of which significantly reduces the energy consumption to manufacture them. Because our batteries use similar materials to the well-established zinc alkaline non-rechargeable battery, there is already an existing recycling infrastructure available for recycling worldwide, further contributing to a decarbonized economy and interestingly, potentially making the batteries even more cost-effective due to lower cost of decommissioning batteries that have fulfilled their lifetime.

To continue reading, please visit our new EES News website.

U.S. commercial real estate to host VPP-connected flywheels and batteries

Blathnaid O'Dea — Thu, 06 Jun 2024 14:26:15 +0000

U.S.-based technology provider Torus has agreed to supply nearly 26 MWh of energy storage for Gardner Group’s commercial real estate portfolio. The project will integrate battery and flywheel energy storage systems (BESS, FESS) with Torus’ proprietary energy management platform.

From pv magazine ESS News site

S-based energy solutions company Torus has announced the signing of a deal with real estate developer Gardner Group to provide its proprietary BESS and FESS technologies in one of the largest commercial energy storage projects in the U.S. state of Utah.

The deal will see 26 MWh of systems installed and supported by Torus’ proprietary software platform, enabling intelligent energy management, demand response capabilities, and seamless integration with renewable energy sources and EV charging infrastructure.

The project will also leverage Torus’ participation in Rocky Mountain Power’s Wattsmart Battery program, which supports grid resilience through the integration of energy storage resources into a VPP ecosystem. The Torus VPP platform enables predictive analytics for demand response, energy arbitrage, and frequency regulation.

“We are thrilled to partner with Gardner Group on this groundbreaking project,” said Nate Walkingshaw, CEO and co-founder of Torus. “This deal demonstrates the growing demand for advanced energy storage solutions in the commercial sector. This is a significant step for energy resilience, sustainability, and cost savings across the Gardner Group portfolio.”

Installation of the project is expected to begin in the fourth quarter of this year, with the completion date estimated to be in early 2026. Once fully operational, the systems will have the capacity to store and dispatch nearly 26 MWh of energy, equivalent to powering nearly 1,000 homes for a full day.

To continue reading, please visit our new ESS News site.

Solar module reliability ranked in scorecard

Anne Fischer — Wed, 05 Jun 2024 13:23:27 +0000

The independent test lab Kiwa PVEL names 53 manufacturers and 388 models--a record number of Top Performers in the ten-year history of the Scorecard.

PV Evolution Labs (PVEL), an independent test lab for the downstream solar industry and member of the Kiwa Group, published its 2024 PV Module Reliability Scorecard. This 10^th edition of the Scorecard names 388 model types of PV modules from 53 manufacturers as Top Performers in PVEL’s testing, the most in the company’s history. Last year the Scorecard named 250 model types among 35 manufacturers.

Kiwa PVEL uses the Product Qualification Program (PQP) to provide the solar industry with empirical data for PV module benchmarking and project-level energy yield and financial modules to identify top performing PV modules.

The PQP was expanded in the fall of 2023 with a new test to address concerns around ultraviolet induced degradation (UVID). It also refocused the hail stress sequence (HSS) on identifying the threshold of glass breakage and modified the mechanical stress sequence (MSS) to target module mechanical durability concerns.

In addition to expanded PQP testing, other updates to the Scorecard include a new Top Performer category for hail, highlighting modules that did not experience glass breakage with ≥40 mm hail, and a higher bar for LID+LETID and PAN Top Performers, with a raised threshold for Top Performer qualification as technologies have improved,

This year’s Scorecard is emphasizing manufacturers who are Top Performers in multiple categories, providing key takeaways on the impacts of various cell technologies and module designs, and offering a deep dive—for the first time– into Kiwa PVEL’s Incidence Angle Modifier (IAM) test results.

“Our 2024 Scorecard showcases strong results across a diverse group of solar module manufacturers, which reflects the excellence and growth we have observed in PV manufacturing in recent years.” said Kevin Gibson, managing director of Kiwa PVEL. “For over a decade, we’ve tested assumptions about solar module reliability and performance while continuing to refine our methodology as the industry continues to innovate with new technologies and module designs. We’re proud that we’re still setting a high bar for manufacturers and providing downstream buyers with the crucial information they need to make educated procurement decisions.”

This partial list shows for which tests each manufacturer achieved Top Performer status with one or more models. Kiwa PVEL noted that in some cases, test results for some test categories were not available at the time of Scorecard publication. Manufacturers are listed by the number of tests, followed by the number of years they have been designated a Top Performer, in alphabetical order. Click here to find model numbers. The full list of Top Performers is a searchable database, where results can be filtered by PQP test, manufacturer name, module type, cell technology, and more.

“With over 50,000 unique visitors to the 2023 edition, our Scorecard is the industry’s go-to resources for module reliability insights. While we applaud the advances in manufacturing and the number of Top Performers listed, we remind buyers to remain vigilant,” said Tristan Erion-Lorico, vice president of sales and marketing at Kiwa PVEL. “We encourage them to explore each page of the Scorecard to better understand the range of test results that we’re seeing every day at Kiwa PVEL’s labs.”

Notable in this year’s test results is that 66% of module manufacturers experience at least one test failure, which Kiwa PVEL said is the highest percentage ever reported.

With the extreme weather events wreaking havoc on some solar installations in recent months, the new Top Performer category for hail shines a spotlight on how the hail testing is performed. Kiwa PVEL focuses almost exclusively for 2.0 mm glass//glass and 3.2 mm glass//backsheet, but results showed that three tested BOMs of 2.5 mm glass//glass showed no glass breakage with 50 mm hail. Kiwa PVEL noted that while glass breakage typically is not considered a Scorecard “failure,” some manufacturers required multiple retests of the same hail diameter before achieving the desired hail test performance, and three manufacturers had modules where the junction box lid fell off due to hail impacts.

To be eligible for the 2024 Scorecard, manufacturers must have completed the PQP sample production factory witness after October 1, 2022, and submitted at least two factory-witnessed PV module samples to all PQP reliability tests, as per Kiwa PVEL’s BOM test requirements.

Kiwa PVEL, a testing lab for downstream solar project developers, financiers, and asset owners around the world, is part of the Kiwa Group.

Access the Scorecard here.

A new federal transmission rule won’t help renewables projects anytime soon

William Driscoll — Tue, 04 Jun 2024 18:25:33 +0000

Although promptly deploying grid-enhancing technologies and advanced conductors could speed interconnection in the short term, a new federal transmission rule will improve interconnection only once new transmission is built, said panelists on a webinar.

A new Federal Energy Regulatory Commission (FERC) order on transmission planning will not help renewables projects connect to the transmission grid “in any sort of timeframe that would benefit” a project now awaiting interconnection, said Kat Gamache, a partner with the law firm Norton Rose Fulbright, on a webinar hosted by the firm.

FERC Commissioner Allison Clements agreed with Gamache, saying “this new transmission rule is not going to help today’s projects,” except to the extent that grid-enhancing technologies including advanced conductors “are brought into economic planning processes and reliability planning processes right away.” Doing so would be “a material improvement,” she said.

FERC Order 1920 requires transmission owners to consider these grid-enhancing technologies in developing the 20-year transmission plans that the order requires.

But Clements, while acknowledging three barriers to deploying the technologies, made the case for their prompt deployment. The first barrier is financial, she said, agreeing with a concern related by the webinar’s moderator that grid-enhancing technologies cost less than new transmission and do not add much to a utility’s rate base, whereas utilities aim to grow by adding to their rate base.

Then there are operational barriers to using grid-enhancing technologies, Clements said, because “even though many of these technologies are common around the world, they haven’t been deployed in the US.” Grid analysts have challenged the federally owned utility Bonneville Power and other transmission providers for yielding to operational barriers.

“There are also corporate barriers,” Clements said, because engineers, their group leaders and executives “are not incentivized to make more room on the grid now.”

But because FERC’s transmission rule will “take years to bear fruit,” Clements advised that “any transmission provider in a state that wants economic development, wants re-onshoring of advanced manufacturing, wants load growth for the value it brings to its state for other reasons, should be saying, ‘Let’s line up these grid-enhancing technologies, because right now they can make space on the system.’”

Turning to FERC’s role, Clements said “there’s a lot more to be done” to improve interconnection, following FERC’s Order 2023 last year to reform the interconnection processes of transmission providers.

“There’s a lot of opportunity” for standardization in the way interconnection applications are processed, she said, and for machine learning “to help us do these studies very quickly.” In addition, there are some “really interesting conversations going on” within grid operator SPP about possibly setting a standard fee per megawatt for interconnecting a generator, she said.

Clements expressed hope that a FERC workshop on September 10 and 11 to consider further improvements to interconnection will involve some of those questions.

Grid Strategies President Rob Gramlich said he expects that in the medium term, transmission regions “that actually follow through and implement” FERC’s new transmission rule will see a great improvement in interconnection speed and cost once new transmission is built.

He gave the example of the midcontinent grid operator MISO, where in late 2008 an agreement was reached to build new transmission to connect 300 MW of wind projects to the grid. Five years later, by 2013, the lines were built, “and almost instantaneously, when those lines were energized, interconnections became extremely fast and cheap” compared to previous years, he said.

Clements reminded listeners that “we have 2.6 terawatts of generation in line to hook up to the grid, and 90-plus percent of that is solar, wind and storage.”

Researchers build 24.4%-efficient perovskite solar cells with room temperature process

Valerie Thompson — Tue, 04 Jun 2024 15:38:10 +0000

Researchers from the U.S. and South Korea have developed a method to make high-quality perovskite films at room temperature. The film was tested in a conventional perovskite solar cell architecture and the result was a power conversion efficiency of exceeding 24%.

An international research team has developed a method to make high-quality perovskite films at room temperature for applications in perovskite solar cells. The novel process avoids thermal annealing and additional post-treatments.

The team selected a perovskite composition known as (Cs_x(FA_0.92MA_0.08)_1−xPb(I_0.92Br_0.08)₃), which was converted into α-FAPbI₃ at room temperature. Further conversion was promoted with the addition of an organic linker known as oleylamine or simply OAm. The method’s effect on quality growth patterns was confirmed by in situ X-ray monitoring.

Furthermore, to demonstrate the feasibility of the process on non-traditional PV substrates and materials, the researchers deposited their perovskite film on a plant leaf, something that would have been impossible with conventional methods.

“The most challenging aspects of the work were to understand the working mechanism and then to demonstrate that the process was gentle enough to deposit perovskite films atop fresh leaves which are very soft and fragile,” research lead author, Thuc-Quyen Nguyen, told pv magazine.

The researchers described the fabrication of cells with a planar p-i-n structure to investigate the effect of cesium (Cs) and OAm on performance and said they used only printable materials. The fabricated devices had an indium tin oxide substrate with a spin-coated layer of MeO-2PACz, which is also known as [2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid.

Then the perovskite absorber went through a two-step spin-coating process and was connected to an electron transport layer (ETL) based on phenyl-C61-butyric acid methyl ester (PCBM) that also relied on spin coating and a bathocuproine (BCP) buffer layer. All of the previous was achieved without thermal annealing. Finally, a 100 nm thick silver metal contact was thermally deposited onto the substrates as cathodes inside a vacuum thermal evaporator.

Reproducibility was assessed via 100 devices with varying amounts of experimental materials. Observing the results, the team noted that the addition of OAm “significantly mitigated” deviations and improved device properties, and that the Cs10+OAm devices exhibited the highest short-circuit current density, open-circuit voltage, and fill factor with the smallest deviations of efficiencies.

The team said that the optimized Cs_10+OAm device achieved “impressive efficiencies” of 23.2%. With an anti-reflective coating, it was increased to 24.4%. It noted that the results surpassed efficiencies attained by previous low-temperature and room-temperature (RT) processed perovskite solar cells (PSCs).

“Through a combination of characterization techniques, we unveiled the morphology and device physics of RT-processed PSCs. Finally, we demonstrated that the annealing-free processing enables the fabrication of high-quality perovskite films on leaf substrates,” concluded the researchers.

The details of the study appear in “Room-temperature-processed perovskite solar cells surpassing 24% efficiency,” published in Joule. The researchers came from three institutions, University of California, Santa Barbara, Korea’s Pusan National University, and Korea Electric Power Research Institute.

Looking ahead, the teams intend to work on integrated PV and indoor PV technologies. “Currently, we focus on the development of efficient semi-transparent solar cells that achieve efficiencies exceeding 12% while ensuring a transparency level of over 30%. These cells are designed for integration into building windows, vehicles, and greenhouses,” said Nguyen.

“Additionally, we are actively engaged in the development of indoor solar cells capable of achieving efficiencies surpassing 40% under LED lighting conditions. This breakthrough has the potential to provide renewable energy to power indoor devices and systems.”

Sunrise brief: Fronius unveils residential string inverter for rooftop solar.

pv magazine — Tue, 04 Jun 2024 12:11:26 +0000

Also on the rise: Vermont becomes first state with Climate Superfund Act. Solar project developers face opposition from Joshua Tree conservationists. And more.

PVRadar offers solar project risk assessments factoring in historical climate data PVRadar Labs has expanded its software platform to include PV project risk assessment functionality, reportedly enabling more realistic performance estimates based on historical climate data.

JinkoSolar claims 33.24% efficiency for perovskite-silicon tandem solar cells JinkoSolar says it has achieved a 33.24% efficiency rating for its perovskite-silicon tandem solar cells, confirmed by the Shanghai Institute of Microsystem and Information Technology under the Chinese Academy of Sciences (CAS).

Vermont becomes first state with Climate Superfund Act The Vermont legislation intends to hold fossil fuel corporations responsible for climate change.

Fronius unveils residential string inverter for rooftop solar The Fronius Gen24 hybrid inverter comes to North America after success in Europe.

Solar project developers face opposition from Joshua Tree conservationists The site of the Aratina Solar Center in Kern County, California, is home to western Joshua trees, and therefore the developer has to comply with the Western Joshua Tree Conservation Act that was enacted in July 2023. Incidental Take Permits authorize renewable energy developers to remove trees with an option to pay a standard mitigation fee rather than complete mitigation actions.

Texas to host 300 MW of geomechanical energy storage projects Quidnet Energy, a provider of geomechanical energy storage (GES) technology, has joined hands with distributed energy resources developer Hunt Energy Network to deliver 300 MW of storage projects in the Electric Reliability Council of Texas (ERCOT) grid operating region.

Perovskite tandem solar panel integrator nets DOE investment

Ryan Kennedy — Mon, 03 Jun 2024 19:42:19 +0000

Tandem PV integrates perovskites with traditional silicon solar panels, a technology that promises increased power output.

Tandem PV, a perovskite solar panel developer, announced it has secured a $4.7 million award from the U.S. Department of Energy (DOE) Solar Energy Technologies Office to advance commercialization of its thin-film solar technology.

The award is part of a larger $71 million investment by DOE in projects that support bolstering the U.S. solar supply chain.

The company develops solar panels that pair conventional silicon cells with perovskite materials for panels, giving them the potential to produce up to 40% more power than traditional solar modules used today, said Tandem PV.

Tandem PV’s design stacks a thin-film perovskite layer on top of the crystalline PV layer, with the two materials absorbing different wavelengths of sunlight. The company is currently producing tandem perovskite panels with about 26% efficiency, which is roughly 25% more powerful than a conventional silicon solar panel today.

Layering of the pervoskite-silicon tandem.
Image: Tandem PV

Solar panel efficiency is an important metric for solar facility developers. More power at a similar price per watt leads to lower labor costs for installation, lower land-acquisition costs, and a lower total cost of ownership for customers, said the company.

“This is Tandem PV’s 10th award from the Department of Energy and we are grateful for its consistent, long-term investment and validation,” said Tandem PV co-founder and chief technology officer Colin Bailie.

The company said its has demonstrated “the equivalent of decades of projected durability” in the lab. Durability has been a key issue to solve for perovskites, which show high efficiencies, but degrade rapidly in the field.

Tandem PV said it plans to obtain independent industry-standard validations of the durability and efficiency of its perovskites during 2024. The company said plans are underway for a first manufacturing facility as research and development efforts advance.

“Thanks to historic funding and actions from the president’s clean energy agenda, we’re able to deploy more solar power – the cheapest form of energy – to millions more Americans with panels stamped ‘made in the U.S.A.’,” said Jennifer M. Granholm, U.S. Secretary of Energy.

Tandem PV, founded in 2016 in Silicon Valley, has raised a total of $33 million in venture capital and government funds including from the DOE, the National Science Foundation and the California Energy Commission.

Tandem PV was selected for the $4.7 million award as part of SETO’s Advancing U.S. Thin-Film Solar Photovoltaics Funding Program.

JinkoSolar claims 33.24% efficiency for perovskite-silicon tandem solar cells

Emiliano Bellini — Mon, 03 Jun 2024 13:30:14 +0000

JinkoSolar says it has achieved a 33.24% efficiency rating for its perovskite-silicon tandem solar cells, confirmed by the Shanghai Institute of Microsystem and Information Technology under the Chinese Academy of Sciences (CAS).

From pv magazine Global

Chinese solar module producer JinkoSolar said it has achieved a 33.24% power conversion efficiency for a perovskite-silicon tandem solar cell based on n-type wafers.

The company said the results have been certified by the Shanghai Institute of Microsystem and Information Technology under the CAS. In its previous attempts, JinkoSolar achieved a cell efficiency of 32.33% for the same device configuration.

“This breakthrough in conversion efficiency for the perovskite/TOPCon tandem solar cell has been achieved through various materials and technology innovations including ultra-thin poly-Si passivated contact technology, novel light-trapping technology, intermediate recombination layer with high light transmittance and high carrier mobility, and efficient surface passivation technology using hybrid materials,” the manufacturer said, without providing any additional technical details.

Chinese manufacturer Longi holds the world record for perovskite-tandem solar cell efficiency, achieving 33.9% efficiency in November 2023. A few months earlier, Saudi Arabia’s King Abdullah University of Science and Technology (KAUST) announced a perovskite-silicon tandem device with an efficiency of 33.7%.

Researchers from Germany’s Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) recently said that the practical power conversion efficiency potential of perovskite-silicon tandem solar cells could reach up to 39.5%. Researchers said exceeding this efficiency threshold requires a change in cell architecture, replacing buckminsterfullerene (C60) with a more transparent electron transport layer, and finding more transparent alternatives to indium tin oxide (ITO) layers.

Sunrise brief: ‘Misguided’ CPUC vote may derail California community solar

pv magazine — Mon, 03 Jun 2024 11:49:00 +0000

Also on the rise: Are false pretenses driving solar cell tariff case? Long-duration energy storage poised to outcompete lithium-ion batteries. And more.

CPUC vote expected to keep California community solar from reaching its full potential Coalition for Community Solar Access says the 3-1 vote ignored the will of the California Legislature and the broad coalition of ratepayer, equity, environmental, labor, agricultural, and business groups who have demanded a functional community solar program for more than a decade.

Alliant Energy completes 200 MW solar project in Wisconsin The project is part of a multi-phase buildout of 12 solar projects totaling over 1 GW.

Long-duration energy storage poised to outcompete lithium-ion batteries While most long-duration energy storage (LDES) technologies are still early-stage and costly compared to lithium-ion batteries, some have already or are set to achieve lower costs for longer durations, finds BloombergNEF.

Solar wafer prices continue to soften, complex international trade situation sparks concerns In a weekly update for pv magazine, OPIS, a Dow Jones company, provides a quick look at the main price trends in the global PV industry.

Gulf heat dome and polar jet stream shape solar outcomes in May In a weekly update for pv magazine, Solcast, a DNV company, reports that a strong polar jet stream and a record-breaking heat dome in May resulted in a stark contrast in irradiance patterns across North America. The western and central USA, along with Mexico, experienced higher than normal irradiance, while the Gulf and East Coast regions faced lower irradiance.

TCL Zhonghuan reveals plans to acquire majority stake in Maxeon Chinese wafer manufacturer TCL Zhonghuan says it wants to invest around $197.5 million to increase its stake in Maxeon from 22.39% to at least 50.1%. A Maxeon spokesperson told pv magazine that the plan would place the company in a solid financial position.

Are false pretenses driving solar cell tariff case? Global manufacturer Canadian Solar challenges prevailing support for tariffs among solar manufacturers, questions the accuracy of capacity estimations, and adverse financial effects.

Producing hydrogen fuel from solar power and agricultural waste

Ryan Kennedy — Thu, 30 May 2024 17:34:09 +0000

Using 600% less voltage to produce hydrogen, a research team at the University of Illinois Chicago has developed a new method for splitting water.

Researchers at the University of Illinois Chicago (UIC) have developed a new method to make hydrogen gas from water using solar power and agricultural waste like manure or husks. The researchers said the method reduces the amount of energy needed to create hydrogen fuel by 600%. The results are published in Cell Reports Physical Science.

The method uses a carbon-rich substance called biochar to decrease the amount of electricity needed to convert water to hydrogen. Combined with using solar power or wind to power the water-splitting process known as electrolysis.

“We are the first group to show that you can produce hydrogen utilizing biomass at a fraction of a volt,” said Singh, associate professor in the department of chemical engineering. “This is a transformative technology.”

Electrolysis represents the most expensive step in the hydrogen fuel lifecycle, representing about 80% of the cost. Recent advancements in producing hydrogen fuel have decreased the voltage required for water splitting by introducing a carbon source to the reaction. However, this process often uses coal or expensive refined chemicals and releases carbon emissions as a byproduct.

The UIC researchers modified the process to instead use biomass from common waste products as the carbon source. By mixing sulfuric acid with agricultural waste, animal waste, and sewage, they produced a slurry of biochar to be used in the reaction.

Image: UIC

The team trialed several different inputs for biochar, including sugarcane husks, hemp waste, paper waste, and cow manure. All five inputs reduced the power needed to perform electrolysis, but the best performer, cow manure, decreased the electrical requirement by 600%, to roughly a fifth of a volt.

With reduced voltage requirements, the UIC researchers were able to produce an electrolysis reaction with one silicon solar cell generating about 15 milliamps of current at 0.5 volt, or less than the amount of power produced by a AA battery.

“It’s very efficient, with almost 35% conversion of the biochar and solar energy into hydrogen” said Rohit Chauhan, the report’s co-author. Chauhan said the utilization rate of biochar represents a world record.

The research team said this utilization for biochar represents a new revenue stream potential for farmers, or an opportunity to become self-sustainable for energy needs.

Orochem Technologies Inc. sponsored the research and has filed for patents on the biochar-hydrogen process. The UIC team plans to test the methods at a larger scale. Stanford University, Texas Tech University, Indian Institute of Technology Roorkee, Korea University also participated in this study.

Sunrise brief: California community solar in peril

pv magazine — Thu, 30 May 2024 12:00:46 +0000

Also on the rise: Technology-neutral proposed tax credit called ‘game-changing policy’. Less than 3% of farmland could power the Midwest. And more.

Strategies to address thermomechanical instability of perovskite solar modules A U.S. research team has investigated the thermomechanical reliability of metal halide perovskite (MHP) modules and cells in an effort to identify the best strategies to improve their stability under thermomechanical stressors. The scientists discussed, in particular, film stresses, adhesion of charge transport layers, and instability under light and heat.

Shedding light on tandem perovskite solar cell progress Perovskite tandem devices are at the front of the queue for commercialization but their characterization presents technical challenges.

Grid analysts challenge Bonneville Power’s pace in adopting advanced conductors As the White House encourages utilities to use advanced conductors to help interconnect new renewable generation, the federally-owned utility Bonneville Power is moving slowly to use the high-capacity conductors, analysts said.

Less than 3% of farmland could power the Midwest An analysis by the Center for Rural Affairs illustrates how using a small fraction of Midwest farmland for solar energy could meet significant renewable energy goals by 2050, dramatically enhancing the financial stability of farms, and challenging traditional views on land use.

Technology-neutral proposed tax credit called ‘game-changing policy’ The U.S. Treasury Department has issued further proposed guidance on the IRA, detailing a path to support a broad array of technologies–including solar– with tax credits, and clarifying many additional tax-related items in its latest guidance.

CPUC’s revised proposed decision could decimate California’s community solar market Just as an increasing number of states are implementing pro-active community solar policies, the California Public Utilities Commission is set to vote on a revised proposed decision that fails to seize on the opportunity to create a vibrant market, according to the Coalition for Community Solar Access.

DOE funding available for distributed energy resource operations software The Department of Energy announced $31 million in funding for research to improve distribution level grid operations of solar, wind, energy storage, and other inverter-based resources.

REC introduces 640 W commercial solar panel The new product contains heterojunction cell technology (HJT) with up to 22.5% efficiency.

Grid analysts challenge Bonneville Power’s pace in adopting advanced conductors

William Driscoll — Wed, 29 May 2024 14:28:46 +0000

As the White House encourages utilities to use advanced conductors to help interconnect new renewable generation, the federally-owned utility Bonneville Power is moving slowly to use the high-capacity conductors, analysts said.

Grid analysts have said that the Bonneville Power Administration, a generation and transmission utility owned by the U.S. Government that serves northwestern states, is moving too slowly to adopt advanced conductors.

Advanced conductors are high-capacity conductors that can replace existing conductors on existing transmission towers.

BPA has “begun the process” to analyze and qualify advanced conductors to increase the capacity of its grid, the utility said in January, adding that the process “can take months or years of physical testing and analyses.”

Analysts at Energy Innovation and GridLab challenged BPA’s approach and that of many other transmission providers, saying that “studying the technology itself rather than relying on real-world deployments or other peer organizations’ testing to approve the technology appears to be the status quo among transmission organizations. This ‘bottom-up’ adoption strategy considerably slows integration of many emerging technologies, not just advanced conductors.” They said BPA’s approach is commonly used at other utilities as well.

The analysts presented their views in a companion report to a technical analysis that found reconductoring could enable 764 GW of transmission-connected solar by 2035.

The U.S. Department of Energy last month flagged reconductoring as having substantial potential to increase transmission capacity, in a “liftoff” report calling for a national collaboration to deploy such technologies.

The White House this week announced a federal-state initiative involving 21 states to modernize the grid, in alignment with its effort to mobilize public and private sector leaders to upgrade 100,000 miles of transmission lines over the next five years. Substantial federal funding for reconductoring is available through three programs made possible through the Inflation Reduction Act (IRA) and the Bipartisan Infrastructure Law (BIL).

One indicator of reconductoring’s potential within BPA’s service area is that from 2000 to 2023, the utility completed six high-voltage projects that enabled interconnection of 7 GW of wind power and 525 MW of solar.

The Federal Energy Regulatory Commission’s recent Order 1920, which requires utilities to develop and periodically update a long-term transmission plan, requires each utility to “consider” advanced conductors when developing their plan.

Shedding light on tandem perovskite solar cell progress

Jonathan Gifford — Wed, 29 May 2024 14:14:25 +0000

Perovskite tandem devices are at the front of the queue for commercialization but their characterization presents technical challenges.

From pv magazine 05/24

On Jan. 31, 2024, researchers from the Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) announced that, alongside perovskite developer Oxford PV, they had produced a full-sized perovskite tandem module with a conversion efficiency of 25%. At 421 W, the dual-glass module’s power output is far from that achieved by the large-format modules manufactured by solar industry giants. Nonetheless, the result was a powerful demonstration of the steps being made toward commercializing what is widely considered the next generation of solar cell technology.

When announcing the result, the Fraunhofer ISE team noted that scientists from its CalLab PV Modules’ calibration laboratory used a “multispectral solar simulator” to measure both the crystalline silicon solar cell and perovskite cells. It allowed for different light spectra to be applied to the cell while under continuous illumination. This required specialized measurement equipment based on LED light sources that were able to provide illumination evenly across the module’s 1.68 m² surface.

“The continuous intensity and spectral stability of the light source is of particular importance especially for tandem devices,” said Johnson Wong, general manager for the Americas at equipment provider Wavelabs. The researchers from Fraunhofer ISE used Wavelabs’ Sinus-3000 Advanced LED module I-V tester for the Oxford PV module.

“Thanks to its optimized light distribution over a long working distance, the tester light source is designed to cast a light field that very closely mimics the sun at every point over the large module area,” Wong added. He said the Sinus-3000 LED tester exceeds A+ class in terms of “spectrum, light uniformity, and stability over time, which play a critical role in the measurement accuracy.”

Accurate characterization

The accurate characterization of perovskite solar devices requires not only new equipment but also novel processes. Longer illumination times are needed; the temperature impact of the light source must be controlled or corrected for; I-V sweeps should be significantly slower than in crystalline silicon cells; and, in tandem cells, their current must be aligned so that the combined power output is not limited.

The PV research community, prospective manufacturers, and equipment suppliers are making strides in overcoming the formidable challenges posed by perovskite solar devices. New, collaborative research projects are being launched and measurement routines are becoming more sophisticated. As a result, confidence is growing that as the prospective PV perovskite manufacturers develop their devices toward maturity, the equipment and processes will be ready.

Sunny prospects

Karl Melkonyan, PV technology analyst with S&P Global Commodity Insights, said that perovskite tandems have “the best chances for commercialization” among next-generation solar cell technologies. Perovskite PV cells can be coupled with either crystalline silicon (c-Si) or thin-film solar cells.

Early perovskite PV devices achieved conversion efficiencies in the low single digits – 3.8% was recorded in 2008. Record efficiencies are now set at regular intervals and are well beyond 25%.

Perovskite tandem devices are extremely promising, primarily because the thin-film perovskite cell plus the “base” c-Si, cadmium telluride, or copper indium gallium selenide layer can capture different light wavelengths, resulting in small-scale research cells with efficiencies beyond 30%.

Translating lab efficiency to larger cells and modules is difficult, however. “While there are many record efficiency achievements of perovskite solar cells reaching 20% and above, the total efficiency of a tandem structure can be much lower than the sum of those individual efficiencies,” said Melkonyan. He noted that the reason for this is often a current mismatch between bottom and top cells.

Measurement challenges

For a PV device to prove its worth, its power output must be able to be measured in a highly accurate, replicable, and standardized fashion. At the end of the day, if a PV module is to be purchased and installed, it is vital that its nameplate power output can be trusted.

Here, as noted in the recent Fraunhofer ISE and Oxford PV result, perovskite PV devices present a host of new challenges. “Yes, the power measurement of a perovskite tandem or multi-junction cell presents challenges and could be quite difficult because very specific spectrally-adjustable solar simulators are required,” said Melkonyan. “Apart from appropriate stabilization methods for different perovskite materials, the processes should include standardized protocols to measure under standard test conditions.”

In late April 2024, Fraunhofer ISE, Oxford PV, Wavelabs, and the University of Freiburg wound up an 11-month investigation into how large-format perovskite tandem PV cells can be accurately characterized. Fraunhofer ISE’s Martin Schubert led the project – abbreviated to “Katana” in German. He said there are two major differences between the characterization of perovskite tandem devices and regular PV modules.

Two factors

“One is that the efficiency may change during illumination,” said Schubert, who leads the quality assurance, characterization and simulation team. “The reason for that is that there is an ion migration in the perovskite cell in which some ions are moving. The second complication is the tandem architecture. By itself, that means we have two solar cells – one on top of the other and with different spectral sensitivity. We need to take care that the top cell gets the right amount of current and the bottom cell gets the right amount of current.”

Ion migration within the perovskite device while under continuous illumination means that the measured efficiency can either increase or decrease over time. This “metastability” necessitates the long illumination time needed for stabilized power output to be ascertained. Complicating things further, different perovskite PV compositions demonstrate varying levels of metastability.

The need for long light exposure, to accommodate metastability, brings heat, even when using LEDs. This means that the measurement of perovskite devices is often carried out at temperatures higher than standard test conditions (STC).

The power output of a photovoltaic device declines as its temperature increases, a factor described as a device’s temperature coefficient. Different PV technologies mean differing temperature coefficients. c-Si solar products, for example, have a larger temperature coefficient than thin film devices. If that is not controlled and accounted for, the result is measurement uncertainty.

Testing equipment with temperature control – essentially a chamber with air conditioning – can reduce this uncertainty in best-case scenarios. Such sophisticated devices, particularly with sufficient scale to accommodate full modules, come at a cost.

The impact of temperature can be corrected for using mathematical models based on accurate temperature readings and can account for the uncertainty higher temperatures can bring. With tandem devices, the temperature sensitivity of both the top and bottom cell must be accounted for – a complex, if not impossible, equation.

Commercial implications

At present, the testing of perovskite devices is carried out within minutes, to account for metastability related to ion migration in the perovskite cell, so that slower I-V sweeps, with multiple power point tracking (MPPT), can be carried out. This is unsuitable for mass production, as many modules need to be rolling off production lines every minute.

Wavelabs’ Wong said that a “more pragmatic test routine” would likely first involve a preconditioning of the module using light soaking, from mass-production light sources. That could then be followed by “a fast I-V sweep using high quality illumination that must fit within the specifications of spectral match, uniformity, and stability,” said Wong. “The fast I-V sweep will likely be done in the order of 100 milliseconds to one second, during which the ions are ‘frozen in’ to their preconditioned distribution and do not significantly redistribute.”

Fraunhofer ISE will be launching a three-year research project in May 2024 that will investigate how “fast and precise measurements” can be developed and executed for perovskite devices, including tandems. The project, abbreviated to “PERLE” in German, will be funded by Germany’s Federal Ministry of Economic Affairs and Climate Action. Fraunhofer ISE’s Schubert said that it is possible that the first findings from the project will be published by May 2025.

Strategies to address thermomechanical instability of perovskite solar modules

Valerie Thompson — Wed, 29 May 2024 12:15:19 +0000

A U.S. research team has investigated the thermomechanical reliability of metal halide perovskite (MHP) modules and cells in an effort to identify the best strategies to improve their stability under thermomechanical stressors. The scientists discussed, in particular, film stresses, adhesion of charge transport layers, and instability under light and heat.

Scientists from Arizona State University published a paper about solving mechanical-based failure mechanisms to make metal halide perovskite (MHP) modules and cells more stable and reliable.

The team asserted that the future of stable and efficient perovskite solar modules lies in understanding the interconnection between various degradation modes, mechanical, thermal, and chemical, under light, heat, and humidity stressors.

“We noticed that there is a significant acceleration in failure rates and reduction in lifetimes of perovskite solar modules in the field when compared to those tested in the lab,” the lead author of the paper, Marco Casareto, told pv magazine. “Specifically, there is little work on testing modules under multiple environmental stressors, such as both light and thermal fluctuations. We wanted to draw attention to this crucial area of research in the hopes of accelerating the progress and commercial viability of MHPs.”

“Yes, and we believe that these factors are connected, based on a shared underlying mechanism related to the mechanical properties of an MHP module,” research co-author, Nick Rolston, told pv magazine.

Their paper highlights issues related to the low fracture energy (Gc) of material layers and interlayer adhesion. “Gc is a material’s resistance to the propagation of a crack, dependent upon both material/interface bonding energy and the ability of a material to deform,” the research group explained.

In addition, it discusses the negative impact of film stresses within the perovskite absorber, how scribing removes material introducing even more interfaces for stress, and the importance of realistic accelerated degradation testing in the lab.

Realistic testing of devices with multiple simultaneous stressors is “crucial” to simulate operation in the field and achieve commercial maturity, emphasized the team. It proposed setting a minimum G_c of 1 J/m² for devices in the lab to ensure that modules can withstand processing and packaging steps without mechanical failure, as well as reduce the potential for delamination and accelerated degradation.

The researchers propose that “engineering compressive stress” and “tuning layer properties” could improve thermomechanical reliability. They also describe encapsulant and perovskite solar module (PSM) materials strategies to increase toughness.

Their findings appear in “Designing metal halide perovskite solar modules for thermomechanical reliability,” published in communications materials.

When asked about reactions to the publication, Rolston said, “We haven’t had much feedback yet since the paper was just released; however, we have been discussing these results with several of the MHP startups that are working toward commercializing the technology, as well as the Perovskite PV Accelerator for Commercializing Technologies (PACT),” referring to the multi-year US Department of Energy’s PACT accelerator, led by Sandia National Laboratories.

There is still a long way to go, as Rolston sees it, but there is optimism about the development of MHP PV panels with operational lifetimes comparable to incumbent silicon or cadmium telluride (CdTe), if there is more of an effort in designing for thermomechanical reliability, rather than just for performance.

Looking ahead, Casareto said, “We’re currently working on validating our hypothesis of a mechanical-based failure mechanism. This involved fabricating MHP individual cells without scribing or encapsulation to establish a baseline of how they degrade under thermal cycling once encapsulated. We are now doing the same with modules soon to elucidate any differences in degradation mechanisms/severity of modules under thermal cycling. We aim to examine the effect of encapsulation, particularly at the scribe lines, as a module is thermally cycled to evaluate what properties are most important/beneficial for a PSM encapsulant.”

Sunrise brief: Battery energy storage tariffs tripled; domestic content rules updated

pv magazine — Wed, 29 May 2024 12:00:25 +0000

Also on the rise: Bringing lithium-sulfur batteries closer to commercialization. Largest solar project in Wyoming moves forward. And more.

U.S. scientists develop air-bridge thermophotovoltaic cells with 44% efficiency U.S. scientists have developed a thermophotovoltaic cell that could be paired with inexpensive thermal storage to provide power on demand. The indium gallium arsenide (InGaAs) thermophotovoltaic cell absorbs most of the in-band radiation to generate electricity, while serving as a nearly perfect mirror.

Bringing lithium-sulfur batteries closer to commercialization Researchers at the University of South Carolina have successfully transitioned their highly-durable lithium-sulfur battery technology from coin to pouch cells and reported competent energy densities.

Guaranteed and transferable tax benefits will make the PV industry too big to fail Trina Solar executive says policies in the Inflation Reduction Act will make or break the future of solar in the U.S.

Largest solar project in Wyoming moves forward The $1.2 billion Cowboy solar project will be built by Enbridge, with 771 MW expected to be fully operational by 2027.

21 states accept the grid modernization challenge The Federal-State Modern Grid Deployment initiative aims to shore up the U.S. energy grid to prepare for both challenges and opportunities in the power sector.

Battery energy storage tariffs tripled; domestic content rules updated Breaking down U.S. market impacts on energy storage from recent policy changes with insights from Clean Energy Associates.

Texas is the proving ground for a new way of electric grid operation Texas is uniquely suited to adopt virtual power plant technology due to its competitive, deregulated market. Its success highlights the “perverse incentive” of vertically integrated utilities in other states to make capital expenditures without discretion to raise profits.

Texas is the proving ground for a new way of electric grid operation

Ryan Kennedy — Tue, 28 May 2024 21:07:44 +0000

Texas is uniquely suited to adopt virtual power plant technology due to its competitive, deregulated market. Its success highlights the "perverse incentive" of vertically integrated utilities in other states to make capital expenditures without discretion to raise profits.

Texas has a unique electric grid. Its grid operation organization, ERCOT, is independent of other states and deregulated, making the state open for business for a market-based approach toward energy generation and transmission.

Texas has been a favorite among utility-scale solar PV developers for a long time, thanks to its business-friendly environment and its lack of substantial local permitting regimes. The state is also operating as a proving ground for the buildout of a more nascent industry: virtual power plants (VPP).

VPPs are defined by their distributed and connected nature. Rather than transmitting power over long distances from a centralized power plant, VPPs use smart software to control a variety of connected energy assets like rooftop residential solar, battery energy storage, smart heating and cooling, and appliances. Homeowners with eligible VPP assets are compensated for exporting power or reducing use at electricity demand events throughout the year.

A panel of experts at the RE+ Texas conference in Houston, spoke on VPP progress in the state. The discussion opened with Stuart Page, senior consultant, Department of Energy (DOE) Loans Program Office asking the audience whether they were currently enrolled in a VPP program. Only two people in a room of hundreds raised their hands. Page then asked how many in the audience had heard of VPP, and most conference attendees raised their hands.

“I bet every single one of you has an energy resource or utilization than can be controlled by an app,” said Page. “Yet none of you are enrolled, despite the fact that there are discounts with your electric bill associated with it.”

Page said that part of the issue with VPP participation is the complexity of programs. Often, they require an opt-in, where the customer must choose to join the VPP program. Page said that VPP providers should instead choose an opt-out model, where customers are automatically enrolled in the program when they buy a smart device like a thermostat or a home battery. He cited a DOE experiment where an automatic enrollment model with an opt-out option increased participation by 400%.

So why are virtual power plants important? VPPs enable intelligent, local distribution of power, sending what is needed when it is needed. VPPs typically support reducing electricity use during times of peak demand, providing a critical service that may be one of the most important low-hanging fruits to pick in the nation’s progress towards decarbonizing energy and lowering energy costs.

VPP technology has shown immediate promise in replacing natural gas “peaker plants” on grids, replacing or preventing the buildout of new resources that are among the dirtiest, most expensive, and least efficient on the grid today.

The virtual power plant commercial liftoff report released by the Department of Energy said that between 2023 and 2030, coincident peak demand on the grid will rise by about 60 GW, from roughly 740 GW to 800 GW of demand.

“At the same time, fossil assets are retiring,” said the report. “Roughly 200 GW of peak-coincident demand must be served with new resources coming online by 2030. Tripling the current scale of VPPs could address 10-20% of this peak demand. This could avoid about $10 billion in annual grid costs, and much of the money that is spent on VPPs would flow back to participating consumers.”

Texas proving ground

Even in a room full of energy industry members and experts, almost nobody attending the RE+ Texas panel session admitted to being enrolled in a VPP. The biggest barrier to adoption has been the creation and implementation of a standardized VPP program, which many states lack.

To automatically enroll customers at the point of purchase as Page suggested, a program needs to be in place to enable it. Sterling Clifford, director of government affairs, Sunnova Energy, a VPP provider shared that many state utility regulators have said VPP technology is a “long way off.”

“But it doesn’t have to be,” said Clifford. “The beginning of the process to the launch of the product was 12 months (in Texas).”

Texas already has 16 MW of energy resources and 7 MW of non-spin flexible demand enrolled in VPP programs.

Part of what enabled such a quick launch of the program was necessity. Ryan King, manager, market design, for the ERCOT said the catastrophic Winter Storm Uri in early 2021 forced the grid operator to look for new sources of reliable, dispatchable supply at the distribution level, while reducing transmission and distribution costs and increasing grid resiliency. ERCOT landed on VPPs as a solution.

Another aspect of Texas’ readiness to adopt VPP programs are its electricity-savvy customers. Texas homeowners and renters are already used to making energy decisions at home, as frequently have to shop for new electricity contracts via a Retail Electricity Provider (REP). Contracts typically last a year or two, similar to how a VPP program enables short-term enrollment.

Texas was also already uniquely well-suited to integrate a VPP program, said King, as ERCOT is already able to value an avoided kWh of electricity, or a dispatched one. This type of valuation is enabled by Texas’ deregulated market, which allow various resources to participate in the market more freely than utilities in other major markets.

Texas has only just begun its VPP enrollment and already has a combined 23 MW of flexible capacity online. King said that VPP compensation for homeowners is “the closest thing to a free lunch,” and that once further program requirements are ironed out, growth will be “exponential.”

As for other states, it may prove more difficult to roll out VPPs. While ERCOT has a transparent market where avoided costs of demand reduction and the value of distributed electricity can be directly understood, other states, like California, have a highly vertical electricity market, where cost allocation reporting is murky.

“A vertically integrated utility – we should just call it a monopoly because that is what they are – don’t always tell the truth about what the exact costs are,” said Clifford.

For Texas, a highly competitive free market have opened the door for adoption of new technologies like VPP. In vertical markets like California, “perverse incentives” may close that door.

DOE’s Stuart Page explained how VPPs lower costs both for grid operators and for ratepayers, but that investor-owned utilities have a disincentive to properly manage their spending habits.

“We have a rate-based system, which means, instead of shaving the peak of my load, we can just build out new stuff,” said Page. “If I can spend $10 billion on that, I get a rate-based profit margin on it. So, I want to spend tons of money. If I use a VPP approach or any other ‘smart’ approach, I don’t get an increase in my profits. So, there’s a perverse incentive for utilities to participate, and we have to change that.”

Bringing lithium-sulfur batteries closer to commercialization

Marija Maisch — Tue, 28 May 2024 15:02:56 +0000

Researchers at the University of South Carolina have successfully transitioned their highly-durable lithium-sulfur battery technology from coin to pouch cells and reported competent energy densities.

From pv magazine EES News

Lithium-sulfur batteries are a promising candidate for high-performance energy storage applications due to their low cost and high theoretical energy density of more than 500 Wh/kg when coupled with lithium metal anodes.

However, developing a highly durable sulfur cathode has been challenging due to the polysulfide shuttling and volume variation of sulfur that leads to chemical and mechanical degradation of the cathode during cycling.

Researchers at the University of South Carolina have made a huge step forward in addressing this issue by developing a simple electrode processing method for producing highly durable sulfur cathodes. These electrodes feature a self-structured binder confinement for sulfur particles using only commercially available sulfur, carbon black, and binder, with no additional components.

The researchers have controlled the dissolution of the binder during the slurry preparation step to form a porous binder/carbon shell structure around the sulfur particles that can entrap the soluble polysulfides and slow down the shuttling mechanism.

The sulfur cathodes achieved through this method offer an outstanding capacity retention of 74% over 1000 cycles, due to a considerable reduction in the lithium-polysulfide shuttling and active material loss. Electrodes with a high areal loading also showed excellent cyclability as well as a high capacity.

The researchers reported these results last year following the completion of the project’s first phase, in which they used coin cells. Now, they are moving to practical battery forms to determine if commercialization is possible.

The team’s current work focuses on pouch cells, which theoretically have the highest energy density since this type has the least amount of waste weight. “Pouch cells usually have lighter and thinner battery casing than the other forms, which leaves most of the volume and weight of the battery for the energy-providing components,” Chemical Engineering Assistant Professor Golareh Jalilvand says.

While the challenges of batteries grow with their size, the USC researchers have reported a fast and successful transition from coin to pouch cells. “We have achieved outstanding lithium-sulfur pouch cells with competent energy densities,” Jalilvand says. “I’m looking forward to seeing the long cycle life and durability of our pouch cells because that’s the last check mark for us and our industrial partner. With that, it might be time to say we have a lithium-sulfur battery that is ready for commercialization.”

Given the long charge-discharge time, the researchers see lithium-sulfur batteries as best suited for applications that do not require fast charging. These include heavy-duty trucks, buses, and other means of transport that need long discharge time, commonly known as milage, and can be kept overnight at charging stations. The technology also shows great potential for stationary applications such as grid-level energy storage as well as space applications.

U.S. scientists develop air-bridge thermophotovoltaic cells with 44% efficiency

Emiliano Bellini — Tue, 28 May 2024 14:59:20 +0000

U.S. scientists have developed a thermophotovoltaic cell that could be paired with inexpensive thermal storage to provide power on demand. The indium gallium arsenide (InGaAs) thermophotovoltaic cell absorbs most of the in-band radiation to generate electricity, while serving as a nearly perfect mirror.

From pv magazine Global

Thermophotovoltaics (TPV) is a power generation technology that uses thermal radiation to generate electricity in photovoltaic cells. A TPV system generally consists of a thermal emitter that can reach high temperatures, near or beyond 1,000 C, and a photovoltaic diode cell that can absorb photons coming from the heat source.

The technology has drawn the interest of scientists for decades, because it can capture sunlight in the entire solar spectrum and has the technical potential to beat the Shockley-Queisser limit of traditional photovoltaics. However, the efficiencies reported thus far have been too low to make it commercially viable, as TPV devices still suffer from optical and thermal losses.

With this in mind, a group of researchers at the University of Michigan in the United States have developed TPV cells that reportedly address these issues and achieve a power conversion efficiency of 44%.

“This level of efficiency could enable thermal battery systems to reach a price point needed to put most of the grid on wind and solar power,” said research’s lead author, Andrej Lenert, told pv magazine. “Such systems have to continuously draw energy from a hot storage material such as graphite as it cools from its maximum allowable temperature. Getting 40% efficiency at storage temperatures as low as 1300 C, versus requiring 2000 C as previously, means these batteries could possibly get twice as much energy per kg of graphite.”

According to Lenert, this result represents a major improvement in TPVs and solid-state heat-to-power generation at large. “It is a culmination of several years of intense research to understand how to minimize energy losses and mechanical issues in air-bridge TPV cells, which we originally reported in 2020,” he added. “Those cells were 32% efficient and relatively fragile, now we are closer to 44% and have a much more robust technology. Though still not at the kW or MW scale, this result demonstrates what is possible with single-junction TPV cells, fulfilling decades-old theoretical predictions made by the TPV community.”

In the study “High-efficiency air-bridge thermophotovoltaic cells,” which was recently published in Joule, Lenert and his colleagues described the cell as an air-bridge indium gallium arsenide (InGaAs) device that can absorb most of the in-band radiation to generate electricity. It can also serve as a nearly perfect mirror, with almost 99% reflectance.

The cell was built with a silicon substrate, an air bridge structure with a thickness of 570 nm, a rear contact made of gold (Au), titanium (Ti), an n-doped InGaAs layer, a membrane layer with a thickness of 1 µm, an InGaAs absorber, and a front contact made of Au, Ti, platinum (Pt), and p-doped InGaAs. Three different absorber layers were tested with energy bandgaps of 0.74 eV, 0.90 eV, and 1.1 eV, respectively.

The air-bridge layer is embedded between the three active layers and the rear Au mirror to enhance backside reflectance and recovery of out-of-band photons. The membrane support layer is intended to minimize buckling of the free-standing semiconductor membrane and ensure a single cavity mode within the air layer.

“The combination of a nanoscale air layer and a relatively high coverage of conductive rear electrodes ensures that the air-bridge thermal resistance is small compared with that of the Si substrate,” the scientists emphasized. “Additionally, the design includes a membrane support layer to minimize buckling of the free-standing semiconductor membrane and ensure a single cavity mode within the air layer.”

The researchers found that the cell with an absorber bandgap of 0.90 eV achieved the best performance. It reached a power conversion efficiency of 43.8% at 1,435 C. “It surpasses the 37% achieved by previous designs within this range of temperatures,” Lenert stated. “We’re not yet at the efficiency limit of this technology. I am confident that we will get higher than 44% and be pushing 50% in the not-too-distant future,” added research co-author, Stephen R. Forrest.”

These results, according to the research group, also promise significant improvements in the device’s round-trip efficiency. “It’s a form of battery, but one that’s very passive. You don’t have to mine lithium as you do with electrochemical cells, which means you don’t have to compete with the electric vehicle market,” Forrest further explained. “Unlike pumped water for hydroelectric energy storage, you can put it anywhere and don’t need a water source nearby.”

Perovskites move into production

pv magazine — Fri, 24 May 2024 16:00:57 +0000

Perovskites remain a great hope for the future of the solar industry, once the possibilities of tunnel oxide passivated contact (TOPCon) and heterojunction PV have been exhausted. A look at the latest perovskite research shows that industry optimism is built on a strong foundation.

From pv magazine

World records for perovskite solar cells have a short shelf life. Until April 2022, a silicon-perovskite tandem cell from Helmholtz-Zentrum Berlin (HZB), a German research organization, led with an efficiency of 32.5%. Researchers at the Photovoltaics Laboratory of the King Abdullah University of Science and Technology (KAUST), in Saudi Arabia, later hit 33.2%, and then 33.7% in May 2023. That record stood for a few months. In early November 2023, a perovskite-silicon tandem cell from Chinese PV manufacturer Longi converted 33.9% of incident sunlight into electricity. “This means that the solar cell efficiency of silicon perovskite tandem cells is now in ranges that could previously only be achieved with III-V semiconductors,” said HZB managing director Bernd Rech, referring to materials such as gallium-arsenide, which offer strong solar cell performance at a much higher cost.

Even single-junction perovskite solar cells without the crystalline silicon or other tandem element are attracting commercial interest. Record after record fell in quick succession in 2023, albeit in increments of tenths of a percentage point. Since November 2023, a group from the Key Laboratory of Photovoltaics at the Hefei Institute in China, with support from German, French, and South Korean scientists, has held the world record with 26.1% efficiency. The successes are based on clever design and the purity of the perovskite crystals. The crystals are, in principle, based on diverse, highly optimized production processes that make it possible to minimize impurities and other defects, which are the most important cause of recombination – where a charge is lost before it can be transported out of the cell.

Knowledge of the fundamental processes within perovskite materials is also growing. For example, Thomas Kirchartz and his team at Germany’s Jülich Research Center discovered a major difference between perovskites and other solar cell materials. In a paper published in the journal “Nature Materials” in January 2024, the group outlined differing roles for “deep” and “shallow” cell-material defects. Kirchartz suspects deep defects, which can occur in silicon, cannot exist in perovskites. “Understanding the processes is crucial to further improving the efficiency of perovskite-based solar cells,” he said.

Lab to fab

“Perovskite solar cells can become a game changer in photovoltaics,” said Michael Powalla, a board member at the Center for Solar Energy and Hydrogen Research Baden-Württemberg in Stuttgart. Values of more than 33% in perovskite-silicon tandem cells could give modules up to 30% efficiency. Most records to date, though, have been achieved with prototypes typically measuring around 1 cm². There is no shortage of unsolved challenges for cells hundreds of times larger. Research institutes and PV companies large and small want reliable, cheap, fast production processes for large cells. Another unresolved issue is the guaranteed durability of perovskite modules that would age as little as possible and give high electricity yields for at least 25 years. “We need everything at the same time: high efficiency, outdoor stability, and scaling with compatible production processes,” said Powalla.

Simple, inexpensive spin coating is sufficient for small tandem laboratory cells. In this process, solutions are thinly distributed on a fast-spinning surface. For larger cells, with an edge length of more than 15 cm, other, less wasteful processes are required. With recent commercial silicon cells boasting up to 21 cm edge lengths, large-area processes are more important.

“Several processes are suitable for this and are currently being tested,” said photovoltaics researcher Kaining Ding, from the Jülich Research Centre. The challenge is that the perovskite crystals must evenly cover the textured surface of the silicon cell without gaps. If the perovskite layer is too thin, the tips of the pyramids on the silicon surface – which are less than 1 micrometer in size – could puncture the perovskite layer and reduce efficiency. On the other hand, if the layer is too thick, it becomes more difficult to collect charge carriers efficiently.

One variant is slot die coating, in which a perovskite solution is applied as an ink-like liquid, and forced through a slot to be evenly applied to a substrate. What then becomes difficult is to precisely control perovskite layer thickness with the process, especially at edges. Perovskite layers can be applied more evenly under vacuum from a vapor phase using a physical vapor-deposition process. The challenge here is finding a perovskite precursor solution that can be completely converted into the necessary vapor phase.

“There is also a hybrid approach that combines the advantages of both process types,” said Ding.

First, a thin, porous, inorganic precursor layer is deposited as a vapor. This is followed by a liquid phase that can be applied by slot die coating or other print- or spray-type processes. This liquid migrates into the porous layer, causing the desired perovskite crystals to grow. Ding said many solar companies are focusing on this hybrid method of wet chemistry and vacuum processes and hope to apply it to full-sized tandem cells in the near future.

A new approach developed by a research group led by Ulrich W. Paetzold, from the Karlsruhe Institute of Technology in Germany, also promises to accelerate developments. The group trained an artificial intelligence device to recognize the smallest deviations in light emission by the cells during the production of tandem devices. The quality of a solar cell could thus be quickly deduced from the light emission.

“Thanks to the combined use of AI, we have an idea of which adjustments we need to make, first and foremost, to improve production,” said Paetzold. This means that experiments can be carried out in a more targeted manner and that production routes can be identified more quickly.

PV modules

Large perovskite silicon tandem cells, or even entire modules, are still hard to find. Anglo-German company Oxford PV has a clear lead, having set up the world’s first series production line for perovskite silicon tandem cells in Brandenburg an der Havel, Germany. At 28.6%, Oxford PV also holds the world record efficiency for a large tandem cell, with a surface area of just over 285 cm².

Others are catching up. In May 2023, Chinese startup Auner presented a tandem cell with a 5 cm edge length and 30.83% efficiency. The company plans to launch a 100 MW pilot production line producing 166 mm cells later in 2024. Swiss manufacturer Meyer Burger also presented a medium-sized (24.5 cm²) cell with 29.56% efficiency as early as 2022, in collaboration with Swiss research center CSEM. Japan-based Kaneka, meanwhile, has hit 28.4% on an 8 cm cell.

Manufacturers of pure perovskite solar cells are striving for faster series production using wet chemical processes such as slot die coating. This is where Chinese companies are making a leap into the market. Last year, for example, Microquanta Semiconductor, based in Hangzhou, started series production of perovskite modules measuring 1.2 m by 60 cm, albeit with efficiencies of less than 20%. Since November 2023, a 1 MW power plant in the Kubuqi Desert in Inner Mongolia featuring those modules has been supplying not only electricity but also valuable data on the durability of perovskite solar cells under real-world conditions.

Silicon solar manufacturer GCL Group has also joined the ranks of perovskite producers with modules measuring 1 m by 2 m and achieving efficiency of 18.04%. The company says a 2 GW production line is currently being prepared in Suzhou, China. Utmolight, which was only founded in 2020, plans to start building a 1 GW production line in 2024 in Wuxi, China, set for completion in 2027. Another 100 MW pilot line is planned for 2024 by startup Mellow Energy. It is targeting 20% module efficiency from modules measuring 1.2 m by 1.6 m, having demonstrated efficiency of up to 22.86% on smaller devices. While those figures are barely competitive with today’s silicon modules, let alone tandem devices, they do offer significantly lower production costs.

Achieving stability

“None of these companies can guarantee the stability of their modules for 25 years,” said Jülich’s Ding. Despite promising results in the laboratory, the durability of perovskite solar cells remains a challenge – both alone and in tandem devices. There is a lack of concrete information from the manufacturers, as well as a lack of measurement data from long-term outdoor use or standards for tough tests that simulate real-life loads of up to 25 years. Laboratory tests on small cells do, however, show how perovskite solar cells can be stabilized, for example, with the addition of certain chemicals. “But there is a gulf between research and industry,” said Ding. Many promising approaches are simply not pursued after publication in renowned scientific journals.

That is precisely the problem that Ding and his colleagues at Jülich and at the HZB want to tackle. Michael Saliba from the University of Stuttgart is also convinced that, with the progress made over the last few years, 20-year stability could, in principle, already be achieved today – provided that the available knowledge is utilized in a bundled manner for the development of sophisticated manufacturing processes.

This means that the hurdles to the low-cost series production of perovskite solar cells – alone or in tandem – appear to be surmountable in the next few years. In a recent paper published in the journal “Science,” Erkan Aydin and his colleagues at KAUST estimated the point at which perovskite-silicon tandem cells will be economically viable compared to standalone silicon. He calculated that higher production costs constitute a premium of 30%. The result is that if a tandem cell loses 2% of its (relative) efficiency every year, the new module should already have an efficiency of more than 32%. If long-term stability can be improved – for example, if a module only degrades by 0.4% per year, similar to today’s silicon PV products – then 24% efficiency would already be sufficient. Then, as forecast by analysts at Rethink Energy, in the United Kingdom, the target of 2 GW of global production by 2026 could easily be achieved. By 2040, some 90% of all solar modules could even contain perovskites.

By Jan Oliver Löfken.

Solar peaks at 123% of grid, supplies 31% of California’s April electricity

John Fitzgerald Weaver — Fri, 24 May 2024 14:30:00 +0000

The Golden State set multiple clean energy records in April, with solar power increasingly dominating the grid, supported by robust energy storage solutions.

California’s recent strides in emission-free electricity and energy storage have garnered global attention, from top-tier publications to outlets on the other side of the globe.

According to data from the California Independent System Operator (CAISO) and record keeping by Stanford Professor Marc Jacobson, “for 45 days straight and 69 of 75, California #WindWaterSolar (electricity) supply has exceeded demand part of each day. On May 20, (supply exceeded demand for) 7.58 h, peaking at 135.4% of demand. On average over 75 days, WWS>demand for 5.3 h/day.”

This performance is bolstered by the extensive use of batteries during the evening electricity peak demand period. As seen in the chart above, the batteries (seen in dark blue) play a crucial role during these ramping periods.

Essentially, the engineers managing California’s power grid have adapted to harness inherently unpredictable power sources.

When it comes to solar, these impressive figures still underestimate the impact of sunlight. This is because they only account for utility-scale generation, with rooftop and behind-the-meter projects contributing an additional 15 GW of capacity worth of electricity – almost equal to utility scale capacity.

For utility-scale supplied solar power, April in CAISO showcased an impressive performance. Generally, April is the third-highest month for solar as a percentage of all electricity, per data from pv magazine USA’s 50 States of Solar report.

However, this past April, the instantaneous “All-Time Max Demand” record was broken four times, rising from an 80.4% record set in April of 2022, to a new record of 97.5% on April 20th this year.

This raises an interesting question: why did ‘All Time Max Demand Served’ jump so significantly this year, especially after it had remained mostly static throughout 2023? It all boils down to increased battery capacity, which has allowed solar to expand its influence more effectively. Notably, we recently saw utility-scale battery capacity surpass 8 GW, which has now began to offset the evening peak demand periods.

Since the electricity for these batteries primarily comes from solar power, perhaps we should also consider that solar is meeting the evening peak demand?

pv magazine USA conducted an analysis of CAISO generation data and discovered that on April 21, solar electricity actually peaked at more than 123% of total electricity generation.

Solar can supply more than 100% of demand due to the net effect of batteries charging. On this date, solar also accounted for almost 38% of all electricity generated within the CAISO region, marking the peak value for the month. Additionally, the following day, CAISO recorded a new high for peak solar output at 18,374 MW.

The chart also highlights the April 8th eclipse – noted with a large dip in generation in light blue around 11 a.m. PST.

According to gridstatus.io, April 21st also marked a new record for battery output at 10:10 p.m., reaching 6,458 MW. This record has since been surpassed multiple times, with the current peak now at 7,528 MW. This record is expected to continue to grow as more utility-scale energy storage is deployed this year.

Over the entire month of April, solar was the largest source of electricity by far, contributing just over 31%. In total, solar combined with hydro, wind, nuclear, and geothermal provided almost 70% of the electricity, with methane generating 19%. Given that imports historically are historically 50% emission-free, this would put the total emission-free electricity used in California in April at approximately 75%.

Bladeless wind energy innovation aims to compete with rooftop solar

Ryan Kennedy — Thu, 23 May 2024 17:28:00 +0000

A compact, “motionless” wind turbine with a magnetic generator designed for large commercial rooftops provides 5 kW of capacity per unit. Aeromine Technologies secured Series A funding for scaling its innovative design.

A new bladeless wind energy unit, patented by Aeromine Technologies, has secured $9 million in Series A funding to accelerate the roll-out of its innovative technology. The scalable, “motionless” wind energy unit can produce 50% more energy than rooftop solar at the same cost, said the company.

Aeromine’s technology is primarily designed for installation on the edge of a large rooftop like an apartment building, a big box store, factory or warehouse, facing the predominant wind direction. The technology leverages aerodynamics like airfoils in a race car to capture and amplify each building’s airflow. The unit requires about 10% of the space required by solar panels and generates round-the-clock energy, as long as the wind is blowing.

Veriten, an energy research, investing, and strategy firm led the funding round, with participation from Thornton Tomasetti. The company said it has received nearly 11,000 inquiries from more than 6,500 companies and currently has a pipeline of 400 qualified projects. Its customers are primarily in industrial, logistics, automotive, commercial, and government sectors.

Aeromine said unlike conventional wind turbines that are noisy, visually intrusive and dangerous to migratory birds, the patented system is visually motionless and virtually silent. And unlike large centralized onshore and offshore wind farms, the space efficient systems are mounted on roofs, bringing power closer to where it is needed, and lessening the need for expensive long-distance transmission infrastructure.

“Distributed power is a key and increasingly strategic element to an evolving ‘all the above’ energy mix,” said Maynard Holt, founder & chief executive officer of Veriten. “We believe that distributed power innovation will play a vital role in helping companies fulfill their need for reliable, reasonably priced electricity and desire for low-impact power.

Each unit weighs just over 1,000 lbs., can withstand winds of 120 mph and can be upgraded to hurricane-resistant models that withstand winds up to 158 mph. The Aeromine generator system is a state-of-the-art rotor / stator system with a 5 kW permanent magnet generator. Product specifications can be found here.

A typical installation would connect 10 units or more, adding 50 kW of capacity to a roof. A ten-unit 50 kW system’s electricity generation varies widely. Aeromine said a roof height of 16 feet and 4.5 meters per second average wind speed would produce about 20,000 kWh per year, while the same 10-unit system on a 50-foot-high roof with 8 meters per second average wind speed would produce over 150,000 kWh per year.

Aeromine told pv magazine USA that “pricing is in line with comparatively rated roof top commercial solar power systems.” The company expects to introduce a commercial solution into the European and North American markets in 2025.

“Aeromine’s proprietary technology brings the performance of wind energy to the onsite generation market, mitigating legacy constraints posed by spinning wind turbines,” said Aeromine chief executive officer David Asarnow.

Quantifying losses from harmonics in solar facilities

Pilar Sánchez Molina — Thu, 23 May 2024 15:12:19 +0000

Gamesa Electric has released a white paper on losses due to harmonics in PV plants, including an independent study that compares the performance of ultra-low total harmonic distortion inverters.

From pv magazine Global

It is estimated that there will be more than 1,675,000 distributed renewable generation inverters connected to electrical grids around the world in 2030. But there is an element associated with these devices that is often overlooked and that is key to a stable grid – harmonics.

In DC/AC inverter-based systems, such as solar and storage, the injection of total harmonic distortion (THD) into the grid can be very detrimental to the generation plant and the grid as a whole. THDs are triggered by variations in solar irradiance and temperature as well as by the use of the inverters themselves, a major source of harmonics due to constant switching on and off.

There are several techniques to reduce the THD at the output of the inverters. In the case of photovoltaic stations composed of several inverters that operate in parallel, phase shifting is the most used. With this technique, the switching signals of all inverters are shifted slightly so that the harmonics due to switching cancel each other out. The result is that the THD of the entire plant is lower than that generated by the individual inverters.

Beyond the immediate impact on power production, harmonics can trigger mechanical vibrations, thereby compromising the longevity of critical components such as transformers. Furthermore, poor antiharmonic strategies can lead to the deterioration of the performance and efficiency of entire systems.

The use of so-called “Ultra-low THD inverters” minimizes the harmful effects of harmonic distortion and avoids not only the hidden losses that occur in the installation, but also the associated reliability and performance problems caused by harmonics. This is the main conclusion of “Unlocking the hidden benefits of ultra-low THD inverters in solar and storage projects,” a white paper that was recently published by Gamesa Electric, a Spanish manufacturer of renewables equipment.

The white paper includes an independent study that compares the performance of an Ultra-low THD inverter, such as the Gamesa Electric Proteus, against other models with a lower capacity to attenuate harmonics. It concludes that, in the case of the Gamesa Electric Proteus, production can be up to 0.35% higher.

“Harmonic distortion or THD is one of the most forgotten sources of losses and reliability problems in solar and storage plants,” said Gamesa Electric Technology Director Andrés Agudo.

As explained in the white paper, inverter design standards are obsolete and compliance with them does not ensure that these problems are avoided.

“It is necessary to design what we call Ultra-low THD inverters, like our Gamesa Electric Proteus model, to minimize losses, which can be very significant, as the study shows,” said Agudo.

Research shows repaired PV modules can perform with acceptable losses

Emiliano Bellini — Thu, 23 May 2024 15:05:41 +0000

A research group has demonstrated the technical feasibility of using repaired solar modules with satisfying results. It also warned, however, that there is an urgent need to define a protocol for evaluating the features of a “viable” repaired panel.

From pv magazine Global

A group of researchers led by Spain’s Centre for Energy, Environmental and Technological Research (CIEMAT) has assessed the performance of 23 partially repaired crystalline silicon solar modules at a 12-year-old PV plant in Spain and has found these panels can operate with minimal losses.

“This research employs a comprehensive standardized approach,” the scientists explained. “It integrates visual inspection, electrical testing, electroluminescence imaging, and thermal imaging techniques to thoroughly evaluate the functional status of these modules and define the nature and extent of defects that persist post-repair.”

The test was conducted following IEC 61215 standard on 18 monocrystalline panels and 5 polycrystalline devices. The monocrystalline products came from two different manufacturers. All panels had a backsheet-glass configuration and their weight ranged from 21 kg to 25 kg. The group also applied the MQT 03 and MQT 15 Module Quality Test standards.

Module failures were identified according to the following classification: snail trails; browned EVA and broken cell; burnt cell; delamination and corrosion as a consequence of EVA degradation; bubbles formation, cracking and burn in the backsheet. “This categorization delineates the progression of power loss from the initial level to a specific point in the operational lifespan of a PV module,” the academics specified.

Through the visual inspections, the team found that the modules showed optical degradation due to delamination and discoloration of the encapsulant. Moreover, it also ascertained that all of the 23 PV modules evaluated passed the dry insulation test, while only one passed the wet leakage current test.

“All modules analyzed exhibit exposed welds on the back sheet, due to bus bar interruption repair,” the researchers stressed. “This condition is not a failure due to the degradation of the module itself but rather a result of the subsequent partial repair, which caused the insulation to fail, making electrical isolation impossible. To fix the insulation of these modules, it is necessary to continue with the backsheet repair, sealing the exposed solder joints and re-testing the modules for wet leakage current.”

The I-V Curve measurements showed that the modules did not suffer from anomalies, although a power reduction was detected, while electroluminescence imaging (EL) demonstrated that around 73% of the panels presented microcracks and darker areas on the periphery of the solar cells.

When they used infrared thermography imaging, the researchers found that “strong hot spots” were detected for 4.35% of the analyzed panels, while “light hot spots” were identified for 74% of the modules. “In this last group, we found that 47 % had featured high temperatures in the junction boxes, attributable to the diode’s activation and further energy dissipation,” they added.

All in all, the analysis showed that the most common defect in the repaired modules is moisture-induced degradation (MID), followed by cracked cells and disconnected areas in cells.

“However, despite the presence of defects, around 87 % of these modules exhibit a reduction of less than 20 % in power,” the scientists stated. “This significant finding suggests that the repaired modules successfully meet the manufacturer’s warranty criteria, indicating their potential for reuse.”

The group also warned, however, that there is an urgent need to define a protocol for evaluating the features of a “viable” repaired panel. “Additionally, it is necessary to raise awareness regarding international standards and Cradle-to-Cradle certification, as this has the potential to stimulate the market demand for second-hand modules with improved sustainability and circularity attributes,” it concluded.

Their findings are available in the paper “Enhancing Photovoltaic Module Sustainability: Defect Analysis on Partially Repaired Modules from Spanish PV Plants,” published in the Journal of Cleaner Production.

Another research team at CIEMAT recently developed a set of techniques to repair ribbon busbar interruptions in PV panels without resorting to expensive electroluminescence images.

Renewables must triple by 2030 to hit net-zero by 2050, says BloombergNEF

Patrick Jowett — Wed, 22 May 2024 14:00:09 +0000

BloombergNEF says in a new report that solar and wind must drive most emissions cuts before 2030 to stay on track for net-zero by 2050. Its net-zero scenario targets a combined solar and wind capacity of 31 TW by 2050.

From pv magazine global

A new report from BloombergNEF says achieving net-zero by 2050 hinges on renewables capacity tripling between now and the end of the decade.

Its latest New Energy Outlook presents a pathway to net-zero by 2050 called the “Net-Zero Scenario” (NZS). It says the window to reach the target is “rapidly closing,” but adds there is still time “if decisive action is taken now.” BloombergNEF warns it will not be possible without accelerated spending, with a fully decarbonized global energy system by 2050 estimated to have a $215 trillion price tag. To reach net zero by 2050, it says progress in the next 10 years is “critical.”

“The period 2024-30 is dominated by rapid power-sector decarbonization, energy efficiency gains and rapid acceleration of carbon capture and storage deployment,” the report says. “Wind and solar alone are responsible for half of emissions abatement during this seven-year period.”

It explains that with renewables driving the bulk of emissions cuts this side of 2030, there will be more time to tackle “hard-to-abate” areas such as steelmaking and aviation, where cost-competitive low-carbon solutions have yet to scale.

BloombergNEF’s NZS says that while the deployment of renewables will continue into the 2030s, the focus will switch to electrification, with electrifying end uses in industry, transport and buildings accounting for 35% of the emissions avoided during this period. It then predicts that the 2040s will rely on a mix of different technologies aimed at hard-to-abate sectors, where hydrogen will account for 11% of emissions reductions.

The report lists nine technology pillars for a net-zero world, which would work to address different elements of the carbonization challenge. BloombergNEF says four of the nine pillars – renewables, energy storage, power grids and electric vehicles – are already “mature, commercially scalable technologies with proven business models.” These are described as technologies which require a significant acceleration to get on track for net zero, but there is little to no technology risk, economic premiums are small or non-existent, and financing models are already at scale.

S will require 2.9 million square km of land for solar and onshore wind projects by 2050, almost 15 times more than was being used by the two technologies in 2023.

It warns that land constraints in some countries – namely, South Korea, Vietnam and Japan – may mean the total land area suitable for solar construction could face saturation, indicating a greater share of less land intensive technologies will be needed in the future. The report says one solution may be using land for solar that can also be used for crops.

“The way in which these segments compete for, and co-exist on, the same land will shape future permitting and zoning rules, particularly if the rollout of low-carbon technologies is seen to threaten food security,” the report predicts.

BloombergNEF also says regardless of whether the world heads for net-zero or it ultimately proves a stretch too far, “the era of fossil fuels’ dominance is coming to an end.” The report predicts that even if the net-zero transition is propelled by economics alone, with no further policy drivers to help, renewables could still cross a 50% share of electricity generation by the end of this decade.

NREL-led consortium releases PV reliability forecasting tools

Valerie Thompson — Tue, 21 May 2024 14:56:52 +0000

The Durable Module Materials consortium (DuraMAT) announced in its latest annual report the availability of new PV forecasting tools, and new research results towards the goal of more reliable PV modules.

From pv magazine Global

The Durable Module Materials (DuraMAT) consortium, established by the United States Department of Energy’s Solar Energy Technology Office (SETO), has released its latest annual report with news about the availability of new PV forecasting tools and new research about certain module degradation trends.

DuraMAT reported the results of its focus on reliability forecasting in 2023, driven by the observation that the PV industry is “innovating so quickly that the performance of modules in the field is no longer always a reliable indicator of what will happen in the future.”

“We awarded six projects under our reliability forecasting call this year,” said Teresa Barnes, DuraMAT director and DOE National Renewable Energy Laboratory (NREL) researcher in a press release.

The reliability forecasting projects addressed ultraviolet-induced degradation, glass fracture mechanics, and degradation mechanisms in encapsulants, as well as how to do faster analysis of failure data. As a result, DuraMAT now has a suite of software tools and data sets, some of which rely on quantitative modeling and rapid validation technologies. The tools cover topics such as mechanical models for materials, wind loading, fracture mechanics, moisture diffusion, and irradiance, and are available in the DuraMAT Data Hub.

“Drawing insights from all these areas should give us the capability to predict the long-term reliability of new module designs,” stated Barnes.

Two degradation mechanisms that received special attention from DuraMAT in 2023 are cell cracking and ultraviolet (UV) degradation. “Cracked cells are a challenge for the solar industry because they can reduce output but often go unnoticed,” said the team. Studies were carried out on quantifying and addressing cell cracking.

“Researchers found that some newer modules with many busbars, half-cut cells, and glass–glass encapsulation are more tolerant of cracked cells and less likely to show power loss,” it said. An outcome of the research is WhatsCracking, a free cell fracture prediction application to assist in making modules that are less sensitive to cell breakage. For example, designing modules that rotate half-cells at 90-degree angles to reduce the chance of cracking under load, as reported in pv magazine. The WhatsCracking app is one of the tools in the DuraMAT Data Hub.

DuraMAT researchers also found that UV-induced degradation is a significant issue in certain high-efficiency products. “These results are important, as the increased degradation related to UV exposure in modern cell types may offset some of the gains predicted from bifacial and other high-efficiency cells,” said the team, adding that DuraMAT will be starting new work to quantify this type of degradation in 2024.

The DuraMAT consortium, which is led by the DOE’s National Renewable Energy Laboratory (NREL), with participation by Sandia National Laboratories and Lawrence Berkeley National Laboratory, includes a 22-member board of solar industry professionals.

Strong state solar policies boost adoption of distributed energy

Anne Fischer — Mon, 20 May 2024 19:58:23 +0000

Of the 29 GW of solar installed in the U.S. in 2023, 31% was distributed solar, according to the Institute for Local Self-Reliance.

The U.S. recently exceeded five million solar installations, with the residential sector accounting for 97% of all solar installations in the U.S., according to data from the Solar Energy Industries Association (SEIA) and Wood Mackenzie.

A recent report, The state(s) of distributed solar—2023 update from the Institute of Local Self Reliance (ILSR), estimates that 29 GW of solar capacity was installed in 2023; 31% of which is distributed solar. Distributed solar is solar that is owned by individuals, small businesses and public entities—and is generated at or very near the site where it is used.

The map below shows how much distributed solar was installed in each state through 2023, relative to population.

For the purposes of the map, community solar in Colorado, Hawaii, Illinois, Maryland, Massachusetts, Minnesota, New Jersey, New York, and Oregon is included as distributed solar.

To arrive at these figures, ILSR added its own figures on state community solar capacity to the U.S. Energy Information Administration’s (EIA) figures on small-scale photovoltaic capacity by state. This sum was divided by state population estimates from the U.S. Census Bureau, resulting in a figure of watts per person. The U.S. EIA did not collect data from Alabama or North Dakota.

A key finding is that 21 states and the District of Columbia have a distributed solar saturation of more than 100 watts per capita.

California, Arizona, Nevada, and Massachusetts all land in the top ten for both distributed solar saturation and total solar generation capacity.

California, Texas, Florida, and North Carolina have the largest overall capacity whereas Hawaii, Massachusetts, Rhode Island and California have the greatest distributed solar saturation, as measured in installed distributed solar capacity per capita.

Several state solar markets have made significant changes since ISLR’s 2022 update. Installed distributed capacity grew by more than 1 GW in Texas (6 GW), California (4.7 GW), Florida (2.5 GW), Ohio (1.8 GW), Virginia (1.2 GW), and Colorado (1.1 GW).

Five states doubled or more than doubled installed capacity in 2023, including South Dakota, Ohio, Pennsylvania, West Virginia, and Arkansas. While doubling capacity is good news, it still may not amount to much as both South Dakota and West Virginia are considered “solar laggards” according to PV Intel’s analysis, based on EIA data.

Other states that saw strong growth include Wisconsin, Indiana, Montana, Louisiana, Maine, and Michigan.

Community solar

Community solar provides a way for people to benefit from solar energy who may be unable to install solar either due to financial restrictions or because they do not have a suitable rooftop for solar.

ILSR’s 2024 Community Power Scorecard states that “a model community solar policy has no cap, has a fair compensation rate, simplifies the billing process for subscribers, meaningfully accounts for the challenge of reaching low- and moderate-income (LMI) subscribers, and rewards other beneficial development or small subscriber-friendly practices”.

ILSR reports that state policies like community solar, net metering, simplified interconnection rules and a renewable portfolio standard carve-out for distributed energy are crucial in promoting the adoption of distributed solar.

The distributed solar report notes that 19 states and the District of Columbia currently have community solar policies and highlights nine states that ILSR calls “solar-enabling” for their strong community solar policies and installed capacity.

Total installed community solar capacity at the end of 2023:

New York 1.72 GW
Minnesota 904 MW
Massachusetts 852 MW
Illinois 251 MW
Maryland 149 MW
Colorado 147 MW
New Jersey 137 MW
Oregon 29 MW
Hawaii 4 MW

ILSR tracks these policies and others in its Community Power Map. According to the ILSR’s Community Power Scorecard, 26 received failing grades in 2024, suggesting that many states have much room for improvement.

ILSR’s State(s) of Distributed Solar analysis is updated annually. For a historical snapshot, explore archived analyses of distributed solar by state in 2022, 2021, 2020, 2019, 2018, 2017, and 2016.

Researchers demonstrate 25%-efficient perovskite-cadmium tandem solar cell

Emiliano Bellini — Fri, 17 May 2024 15:21:59 +0000

University of Toledo researchers say the cell has a top perovskite cell with a transparent back contact made of indium zinc oxide and a commercially established cadmium telluride bottom device. They claim the champion tandem cell has the potential to reach a 30% efficiency.

From pv magazine Global

A research group at the University of Toledo in the United States has designed a four-terminal (4T) tandem solar cell with a top device relying on a perovskite absorber with a tunable wide-bandgap and a bottom cell using a commercially established narrow-bandgap absorber technology made of cadmium telluride (CdTe).

“While a lot of work has been done on perovskite-silicon, perovskite-CIGS, and perovskite-perovskite tandem cells, perovskite-cadmium telluride tandem solar cells are relatively unexplored,” the scientists said. “Although the efficiency potential of CdTe-based tandems is likely lower than CIGS-based tandems due to the higher bandgap of the CdTe bottom cell, the broader commercial success of CdTe solar cells makes them a point of interest in investigating thin-film tandem applications.”

The academics said a key element of the solar cell is the transparent back contact (TBC) technology used for the top tunable wide-bandgap perovskite cell. For the construction of these contacts, they used indium zinc oxide (IZO) as an alternative to well-established indium tin oxide (ITO).

They prepared the IZO films through the radio frequency (RF) magnetron sputtering technique, which is an approach involving alternating the electrical potential of the current in a vacuum environment at RFs.

They also explained that their efforts were aimed at identifying the ideal IZO thickness, as this plays a crucial role in improving the performance and optical transmittance of the semitransparent perovskite top cell by increasing the perovskite bandgap allowing more long-wavelength photons to transmit and enter the CdSeTe bottom cell. In turn, this compensates for a typical optical loss factor in a 4T tandem configuration.

The top cell was constructed with a substrate made of glass and indium tin oxide (ITO), a hole transport layer (HTL) made of nickel(II) oxide (NiOx), a layer made of a phosphonic acid called methyl-substituted carbazole (Me-4PACz), the perovskite absorber, an electron transport layer (ETL) relying on buckminsterfullerene (C60), a tin oxide (SnOx) buffer layer, and the IZO back contact.

The bottom cell was designed to have a substrate made of glass and ITO, an ETL made of tin oxide (SnO2), a cadmium telluride (CdTe) absorber, a cadmium selenium telluride (CdSeTe) layer, a copper thiocyanate (CuSCN) HTL, and a gold metal contact.

Both cells were covered with an anti-reflecting coating.

The best tandem cell configuration was achieved when the absorber of the top cell was tuned to have an energy bandgap of 1.76 eV. With this value, the device reached an overall power conversion efficiency of 25.1%.

The top cell was found to achieve an efficiency of 17.93%, an open-circuit voltage of 1.315 V, a short-circuit current of density of 17.11 mA cm², and a fill factor of 79.7%. The bottom cell showed an efficiency of 7.13%, an open-circuit voltage of 0.842 V, a short-circuit current of density of 11.15 mA cm², and a fill factor of 76.0%.

“The result proves the concept that 4T perovskite–CdSeTe tandem configuration can be used to improve the efficiency of commercial CdSeTe thin-film solar cells,” the researchers stated, adding they are currently outlining a roadmap to increase the device’s efficiency to 30%. “Our analysis reveals that high-efficiency 4T perovskite–CdSeTe tandem solar cells are feasible with the future advance of both PV cells.”

The details of the new cell design can be found in the study “Four-Terminal Perovskite–CdSeTe Tandem Solar Cells: From 25% toward 30% Power Conversion Efficiency and Beyond,” which was recently published in RRL Solar.

The University of Toledo developed several types of CdTe solar cells over the past years. The devices include, among others, a 20%-efficient cell based on a commercial tin(IV) oxide (SnO₂) buffer layer, a 17.4%-efficient device using a layer of copper-aluminum oxide to the rear side of the CdTe thin film, and a solar cell based on an indium gallium oxide (IGO) emitter layer and a cadmium stannate (CTO) transparent conductor as the front electrode.

Solidion seeks to provide sodium-based electrolytes as an alternative to lithium-ion batteries

Michael Puttré — Thu, 16 May 2024 15:00:49 +0000

The company says the technology’s better cycle times and potential lower costs would benefit grid storage and EV sectors.

A recent report by the International Energy Agency said lithium-ion batteries remain the key storage technology for the energy and transportation sectors. While mining for lithium is keeping pace with increasing demand, lithium refining and production of battery packs is concentrated in China, which causes some concerns in the West over supply chains and market dominance.

Sodium is emerging as a viable material for solid state batteries for many of the same energy storage applications that now favor lithium-ion systems.

Bor Jang, chief science officer and board chairman of Solidion Technology, an Ohio-based developer of solid battery technologies, told pv magazine USA that as many countries become dependent on batteries for important sectors of their economies, they will be prompted to search for alternative formulations to those based on lithium, which is relatively rare.

“Sodium, by contrast, is much more abundant in the Earth’s crust and oceans and is evenly distributed around the world,” he said.

In addition to its abundance, which leads to lower costs and easier supply chains, sodium-ion formulations have advantages in faster recharge rates and improved fire safety over lithium-ion ones, Jang said. The tradeoff is that sodium-ion batteries have less energy density (watts per kilogram), which translates into shorter ranges for electric vehicles and less overall storage capacity for grid operators for the same footprint.

However, Jang said, sodium-ion batteries are perfectly suited to EV uses where a 150-mile range would not be a burden, such as for local utility fleets or commuter driving, and where their faster recharge cycles would be appreciated, as would the projected lower price. Similarly, grid-storage facilities where footprint is not an issue would benefit from recharge rates and fire safety characteristics.

On the manufacturability side, Jang said sodium-ion batteries could be produced in factories that currently make lithium-ion batteries with only minor changes to the equipment.

“Solium-ion batteries have the potential to be useful across a wide range of applications, not just those dominated by lithium-ion technology” Jang said. “They can be used in place of lead-acid batteries, for example. Such demand will bring down prices.”

A materials scientist by education, Jang said he turned his attention to solid-state battery research and development about 20 years ago as the needs of the proposed energy transition from fossil fuels to non-emitting sources clearly would require a dramatic increase in energy storage capacity, particularly with renewable generators such as solar and wind. He founded a number of companies focused on the supply of materials for solid state battery electrolytes, anodes and cathodes.

Earlier this year, he saw the merger of his Honeycomb Battery Co. with Nubia Brand International Corp. which gave Solidion status as a publicly traded company. It joins a number of competitors hoping to commercialize sodium-ion batteries.

Jang said Solidion is working with the U.S. Department of Energy through one of the national laboratories, not announced, and the University of Texas, Austin, to improve the performance of sodium-ion battery technology. In particular, the focus is on improving the energy density electrolyte and replacing expensive cobalt and nickel in battery components.

Powering drones with ultra-thin, flexible perovskite PV cells

Valerie Thompson — Tue, 14 May 2024 14:15:29 +0000

An Austrian research team has demonstrated that lightweight, flexible and ultra-thin perovskite solar technology can power palm-sized autonomous drones.

From pv magazine Global

A team from Johannes Kepler University Linz, Austria has developed lead halide perovskite solar cells that measure less than 2.5 μm thick with a champion specific PV power density of 44 W/g, and an average performance of 41 W/g, which they were able to integrate into modules to power palm-sized quadcopter-style drones.

The technology exhibited promising stability results under several standard tests, as well as the energy harvesting potential sufficient to recharge the vehicle’s batteries. The details of their research appear in “Flexible quasi-2D perovskite solar cells with high specific power and improved stability for energy-autonomous drones,” published in nature energy.

The study’s large-area photovoltaic module, which measured 24 cm2, enabled the autonomous operation of the drone that extended “beyond what is possible on a single battery charge while eliminating the need for docking, tethered charging or other forms of human involvement.” The perovskite solar modules contributed just 1/400th of the drone’s total weight.

The group tested several alpha-methylbenzyl ammonium iodide (MBA) combinations in the top perovskite absorber layer, with PEDOT:PSS combining hole transport and electrode functions. The longest lifetime of the various MBA formulations included cesium (Cs), indicating “a reduction of non-radiative recombination pathways due to the presence of MBA and Cs”, according to the researchers.

The substrate was an “ultrathin” and transparent-conductive-oxide-free 1.4-μm-thick polymer foil coated with a layer of 100 nm aluminum oxide. It effectively served as a “barrier” to moisture and gases.

“This type of device has no room for typical encapsulation approaches, which are just too thick. Instead, the team relied on the MBA perovskite top layer’s large, bulky crystal formation to effectively passivate the surface, and for the substrate, the aluminum oxide layer applied with atomic layer deposition (ALD) tool serves to protect from the external conditions, but still stay lightweight and flexible,” research leader, Martin Kaltenbrunner, told pv magazine.

Indeed, the paper notes, for example, that the water vapor transmission rate (WVTR) of the “coated ultrathin substrate was measured to be about 35% lower” when compared to the reference designs, which were methylammonium lead iodide (MAPbI3) devices.

Other features of the perovskite cell include an electron transport layer made of phenyl-C61-butyric acid methyl ester (PCBM) with a titanium oxide interlayer, and a metal top contact, which the group pointed out could be made interchangeably of gold, or chromium/gold, or low-cost aluminum.

“It is important in our perovskite solar research to use precursors that are synthesized in as few steps as possible. Straightforward synthesis is key because we want the technology to be scalable and to keep material production costs in check,” said Kaltenbrunner.

From cells to module

The study’s small area perovskite solar cell measured 0.1 cm2 with an open circuit of 1.13 V, a short-circuit current density of 21.6 mA cm−2, a fill factor of 74.3%, and a power conversion efficiency of 18.1 %. The champion cells reached an open-circuit voltage of 1.15 V, a fill factor of 78%, and an efficiency of 20.1%.

The larger device had an active cell area of 1.0 cm2, with a mean open-circuit voltage of 1.11 V, a short-circuit density of 20.0 mA cm−2, a fill factor of 65.9%, and an efficiency of 14.7. The champion device reached an efficiency 16.3%, stated the research team.

The module for powering the drone had 24 interconnected 1 cm2 solar cells. The energy-autonomous hybrid solar-powered commercially available quadcopter-type drone weighed just 13 g.

The stability and prolonged outdoor operability were tested. For example, both the small- and large-area unencapsulated solar cells maintained 90% and 74% of initial performance, respectively, after 50 h continuous maximum power point tracking (MPPT) in ambient air. In addition, an external lab validated performance and properties of the perovskite composition.

The team asserted that it demonstrated the “broader benefits of using a quasi-2D perovskite active layer” and that it outperforms “other compositions in this field”, adding that the performance, stability, and usability of the ultra-lightweight perovskite solar technology is both a “portable and cost-effective sustainable energy harvesting” solution.

As a drone charging system, it is a step on the path to “perpetual-operation vehicle development” for both aerospace and terrestrial applications, it asserted.

The team has plans for further research along these lines. “We will continue to work continue to develop the AlOx barrier substrate technology, scalable deposition techniques, and to scale up to even larger modules, measuring at least 10 cm X 10 cm. We are intent on the development of lightweight, flexible PV solutions to power all kinds of robotics and autonomous vehicles,” said Kaltenbrunner. “There is great potential for deployable, flexible solar PV in both earth and space applications.”

FERC transmission rule to shore up the nation’s power grid

Anne Fischer — Tue, 14 May 2024 14:08:31 +0000

The ruling, which is being praised by industry groups, is the first time in more than a decade that the Federal Energy Regulatory Commission has addressed regional transmission policy as well as the need for long-term transmission planning.

The Federal Energy Regulatory Commission (FERC) voted to shore up the nation’s transmission grid to meet growing renewable energy generation.

This is long-awaited news for the solar industry, as the U.S. Department of Energy has estimated that 54,500 GW-miles of additional within-region transmission capacity is needed for a clean grid. An improved grid aligns with the move to clean energy as supported by the Inflation Reduction Act and the Biparistisan Infrastructure Law.

The Solar Energy Industries Association (SEIA) has been involved with this rulemaking proceeding over the past two years, advocating for reforms to the transmission planning process to account for all the benefits that clean energy offers.

“We’re pleased FERC took several steps to improve America’s outdated transmission system, including following SEIA’s recommendations requiring transmission providers to engage in long-term regional planning,” said Melissa Alfano, senior director of energy markets and counsel for SEIA.

The ruling, Order No. 1920, is the first time in more than a decade that FERC has addressed regional transmission policy as well as the need for long-term transmission planning.

“Our country is facing an unprecedented surge in demand for affordable electricity while confronting extreme weather threats to the reliability of our grid and trying to stay one step ahead of the massive technological changes we are seeing in our society,” said FERC Chairman Willie Phillips. “Our nation needs a new foundation to get badly needed new transmission planned, paid for and built. With this new rule, that starts today.”

With this ruling, transmission providers must conduct long-term planning for regional transmission facilities and determine how to pay for them. It also provides for “right sizing” transmission facilities, which amounts to expanding transmission when it needs to be replaced. Furthermore, it spells out the role of states in planning, selecting, and determining how to pay for transmission lines.

[Read The 50 states of grid modernization.]

“We need to seize this moment,” Chairman Phillips said. “Over the last dozen years, FERC has worked on five after-action reports on lessons learned from extreme weather events that caused outages that cost hundreds of lives and millions of dollars. We must get beyond these after-action reports and start planning to maintain a reliable grid that powers our entire way of life. The grid cannot wait. Our communities cannot wait. Our nation cannot wait.”

The ruling also details how FERC can exercise its authority over states if they fail to act on a transmission project outlined by the National Interest Electric Transmission Corridors (NETC). The Department of Energy designated ten NETCs, eight of which would facilitate transmission between grid regions; one would expand transmission within the Mid-Atlantic’s PJM grid region; and one would expand transmission in the Northern Plains.

Also included in the ruling are advanced technologies to modernize the grid, such as advanced conductors and grid-enhancing technologies.

Grid-enhancing technologies (GETs) were cited by an RMI study as potentially capable of saving project developers collectively hundreds of millions of dollars in interconnection costs compared to default network upgrades, while the project-level savings “could be the difference” that allows a developer to build a project instead of dropping out of the queue. The study notes that GETs can also be installed more quickly than other network upgrades.

“WATT applauds FERC for requiring advanced power flow control, dynamic line ratings and transmission switching in regional transmission plans,” said Julia Selker, executive director of the WATT Coalition, a group that advocates for policy that supports wide deployment of Grid-Enhancing Technologies. “These technologies are often cost-effective tools to increase grid capacity and improve flexibility to manage outages and other contingencies. Grid Enhancing Technologies will be vital to achieving the seven economic and reliability benefits in the rule, especially production cost savings, reducing grid congestion and improving performance in extreme weather.”

The energy grid in the United States was built in the 1960s and 70s and is hard pressed to handle the extreme weather events caused by climate change, let alone the renewable energy needed to meet energy goals.

“An expanded transmission system is not just a must for climate, it’s a must for running a reliable, affordable grid. The power system is changing, and this rule ensures the nation’s power grid will advance with clarity and consistency – rather than a haphazard approach that ignores the full range of benefits that new transmission can bring,” said Alfano.

Alfano noted that climate-fueled disasters pose huge challenges to the grid. “This rule will help shape a power grid that optimizes the capabilities of clean energy while prioritizing reliability and affordability,” she said. “In addition, FERC’s backstop siting rule will help ensure that no one state can veto transmission lines that are in the general interest of the nation.”

Reflective ground covers boost solar energy production

Ryan Kennedy — Fri, 10 May 2024 18:45:16 +0000

Researchers in Canada are testing the use of reflective surfaces to boost electricity production in bifacial solar panels.

A team of researchers at the University of Ottawa are testing the use of artificial reflectors to boost solar production. The study was published in Progress in Photovoltaics.

In Canada and other northern climates, it is common to use bifacial solar panels, which can collect light and convert it to electricity on both sides of the panel. These cold climates often have snow on the ground, creating a highly reflective surface that boosts bifacial production.

University of Ottawa’s Sunlab, along with the U.S. National Renewable Energy Laboratory (NREL), collaborated on a project that tested the efficacy of creating artificial surfaces that can mimic the benefits of the high reflectivity of snow.

“High-albedo locations demonstrate a boost in performance, with bifacial gains reported of over 19% in snowy months,” said the report. “The bifacial PV industry has demonstrated an interest in extending this energy gain to non-snowy locations year-round using artificial reflectors.”

The team found that placing white reflective surfaces directly under solar panels can increase total energy output by up to 4.5%.

The study calculated a maximum viable cost for these improvements of up to $2.50 to $4.60 per squared meter, including both material and installation, at the Golden, Colorado test site.

“Higher breakeven material costs are possible in systems with higher initial levelized cost of electricity (LCOE). For example, we found breakeven installed costs of $3.40–$6.00 squared meter for Seattle, Washington, with 60% reflective material.”

The impact of artificial reflectors depended strongly on location, with locations with higher LCOE and lower energy yield benefiting more from the addition of reflectors than locations with low LCOE and high energy yield.

“We found that highly reflective white surfaces can boost solar power output,” said Mandy Lewis, the study’s lead author. “Critically, these reflectors should be placed directly under the solar panels, not between rows, to maximize this benefit.”

Lewis said the research will be helpful in boosting solar production in geographically diverse regions. Generating more power per unit of land area makes reflectors a potential match for densely populated areas, where space limitations exist for solar installations, said Lewis.

The report found that 70% reflective material can increase total incident irradiance by 1.9% to 8.6% and total energy yield by 0.9% to 4.5% annually after clipping is considered with a DC–AC ratio of 1.2.

“Clipping has a significant effect on reflector impact and must be included when assessing reflector viability because it reduces reflector energy gain,” said the report.

Longi announces 27.30% efficiency for heterojunction back contact solar cell

Emiliano Bellini — Thu, 09 May 2024 17:07:57 +0000

The Chinese module manufacturer said the new efficiency record was confirmed by Germany’s Institute for Solar Energy Research (ISFH).

From pv magazine Global

Chinese solar module manufacturer Longi has achieved a power conversion efficiency of 27.30% for an HBC solar cell. Germany’s Institute for Solar Energy Research (ISFH) has confirmed the result.

The new efficiency record beats the previous world record of 27.09%, which was also set by Longi at the end of last year.

At the time, Longi said the result was enabled through a new laser graphical process that costs less than conventional high-cost photolithography processes.

“This substitution has effectively reduced the cost of the BC cell,” the company said in a statement, noting that the HBC architecture also minimizes the reliance on traditional indium-based transparent conductive oxide (ITO). “This breakthrough has propelled the commercialization of HBC solar cells, featuring independent intellectual property and cost-effectiveness.”

In early November, Longi announced a power conversion efficiency of 33.9% for a perovskite-silicon tandem solar cell.

It claimed the world’s highest efficiency for silicon cells in November 2022, with a 26.81% efficiency rating for an unspecified heterojunction solar cell.