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 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 (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”

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 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.

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.”

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.”

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.

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 

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.

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.

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.”

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.”

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.

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.

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.

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.

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.

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.

From pv magazine Global

A global group of scientists led by the Massachusetts Institute of Technology (MIT) developed a novel low-cost solar-powered brackish water desalination system that can reportedly reduce the levelized costs of water (LCOW) compared to conventional PV-driven desalination systems.

The proposed desalination system utilizes time-variant electrodialysis reversal (EDR) technology, which the researchers developed as a flexible variation of traditional EDR desalination. “Our research aims to address water scarcity in rural India where the majority of underground water is too saline to drink. The grid electricity access and stability are not good, suffering from frequent power cuts,” corresponding author, Wei He, told pv magazine.

“An EDR module is made up of a stack of ion exchange membranes and uses an electric field to move ions from the dilute flow channels to the brine flow channels between each membrane,” said the research group. “This electric field can be intermittently reversed to prevent the build-up of scale on the membrane.”

However, due to solar energy’s intermittent nature, the classic EDR is not a perfect fit. It requires constant power for its operation, and therefore, PV-EDR plants need the support of batteries or oversized solar systems, particularly at the start and end of the day when solar power is low.

“To overcome these problems, we have developed a flexible batch EDR technology that incorporates a time-variant voltage and flow rate adjustment,” the academics explained. “A model-based control method enables the EDR system to align its power consumption with available solar power at each time step while optimizing water production under varying solar conditions.”

To control the operation, the team created a feed-forward, model-based main controller running in Python to compute the optimal pump flow rate and the EDR stack voltage based on real-time sensor readings. A prototype was built at a research facility, closely reflecting the typical design parameters and operational conditions for a community-scale PV-EDR system sized to produce 6 m3 freshwater per day. It was powered by a solar panel with an area of 37 m2 and a tilt of 30 degrees.

This pilot system was tested for single-day and six-day analysis and compared to the traditional constant-operation EDR system. Both systems were fed with water with an average starting salinity of 970 mg l−1. The system was set at a conservatively low water recovery ratio of 60%.

“The flexible system is able to directly use 77% of the available solar energy on average compared with only about 40% in the conventional system (a 91% increase),” the scientists emphasized. “This suggests that a conventional system would require much more solar panel area to operate directly (that is, without any energy storage), increasing capital costs.”

In addition, the analysis showed that the average minimum battery capacity required for the flexible system was 0.27 kWh, a 92% reduction compared to 3.3 kWh in the constant system. “Finally, the results show that the flexible system can reach its production volume up to 54% faster than the conventional system,” they added.

Following the experimental results, the researchers conducted a cost analysis case study for the usage of such a system in Chelluru, a rural village in India located near Hyderabad. Using computer simulation and optimization, it was compared to a conventional PV-EDR system, a state-of-the-art constant PV-EDR, and a commercial on-grid reverse osmosis (RO) desalination system. “RO uses pressure to force water through a polymer membrane, while its constitutive ions are blocked by the membrane,” the group said.

“The optimized levelized cost of water (LCOW) achieved by the proposed flexible PV-EDR system is US $1.66 m−3, which improves the cost by 22% compared with the current state-of-the-art PV-EDR system and by 46% compared with the conventional PV-EDR system,” the scientists found. “The LCOW for on-grid RO is US $1.71 m−3, 3% above the LCOW of flexible PV-EDR.”

Their findings were presented in “Flexible batch electrodialysis for low-cost solar-powered brackish water desalination,” published in Nature Water. The team included researchers from King’s College London in the UK, and Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (HI ERN) in Germany.

“For the next step, exploring the long-term performance and broadening the application scope of our PV-EDR technology beyond brackish water desalination presents a significant opportunity to address a wider array of global challenges related to water and liquid waste treatment,” concluded He.

From pv magazine global

Scientists from South Korea’s Korea Aerospace Research Institute (KARI) and the Korea Electrotechnology Research Institute presented in a new paper the advancements of their Korean Space Solar Power Satellite (K-SSPS) project. Namely, they presented a conceptual design of the satellite, its end-of-life disposal method, and a first pilot system and experiment.

“The objective of Japan is to develop gigawatt-level space solar power satellites (SSPS) by 2050, and China aims at megawatt-level SSPS by 2035 and gigawatt-level satellites by 2050,” corresponding author, Joon-Min Choi, told pv magazine. “Although Korea entered the field of SBSP relatively late, it has made notable progress. These advancements exemplify Korea’s commitment to achieving Space-Based Solar Power (SBSP) and contribute to the ongoing collective efforts in this field.”

As for the proposed design of the power-transmitting satellite, the group emphasized that it is “not derived from rigorous analyses but rather serves as system requirements for commercial viability.” Per this design, the system will have a mass of 10,000 tons and transmit microwave at a frequency of 5.8 GHz to Earth via a 1.0 km2 antenna. The microwaves can be converted on the ground to usable electricity via rectennas, which are special receiving antennas that are used for converting electromagnetic energy into direct current (DC).

The system is planned to have two solar array wings of 2.2 km × 2.7 km each. It will use 4,000 sub-solar arrays of 10 m × 270 m, made out of thin film roll-out, with a system power efficiency of 13.5%. On the ground, the researchers propose to place 60 rectennas with a diameter of 4 km along the Korean Demilitarized Zone (DMZ). In that case, 60 satellites will have to correspond to the 60 rectennas.

“If each rectenna could generate 2 GW, the total power collected would be 120 GW, providing approximately 1 TWh of electricity per year,” they said. “This amount exceeds South Korea’s electricity consumption in 2021 (0.5334 TWh) and surpasses the combined electricity consumption of South and North Korea for a certain period of time.”

Based on previous literature, with a lifetime of 30 years, such a structure could provide electricity at a price of  $0.03/kWh. Per the proposal, the satellite bus will first get into the low Earth orbit (LEO), where the main structure and the solar arrays will be installed. After conducting some tests, harvested energy will power the K-SSPS journey from the LEO to the geostationary orbit (GEO).

The disposal method proposed is to intentionally collide the structure at the end of its lifetime into the lunar surface, preferably on the rear side of the Moon. This will ensure the complete removal of its debris from space while also potentially recycling valuable materials for future lunar colony residents.

“As we stand on the verge of commercialization, it becomes imperative to scrutinize and illuminate the inherent weaknesses of SBSP and devise effective solutions or mitigation strategies,” the group said. “Of paramount importance is the necessity to articulate a comprehensive disposal methodology for the mega-size structures associated with SBSP. This substantiation is crucial for justifying the development of SBSP.”

According to the researchers, a pilot system aimed at validating power transmission capabilities and verifying the functionality of deployable/expandable devices can be realized in Korea already in the 2020s. The proposed pilot consists of two small 60 × 60 × 80 cm satellites, each with a mass of 120 kg. One of those will act as an electric power transmitter, while the other satellite serves as a receiver.

“The total solar panel area of the power transmission satellite is not sufficient to continuously transfer the power generated by the Sun, despite the solar panels providing a minimum of 0.39 kW of power,” they said. “To overcome this limitation, the power transmission satellite is equipped with two additional batteries, each weighing 4 kg, allowing for the storage of as much solar energy as possible before transmitting the power to the power reception satellite.”

They also explained the input power of the transmitter will be 8.6 kW, while the output power of the transmitter will be 3.44 kW. They calculated the average output power for different distances, ranging from 100 m to 1,000 m. Per their calculation, for 100 meters, the output load is 162 watts, while for 1,000 meters, it can be as low as 0.12 watts.

In 2019, the KARI set a goal of developing a LEO Space Solar Power Test Satellite by 2040 and a GEO SSPS by 2050. Those goals were also adopted in 2022 by the “KARI Technology Strategy.” The current developments were presented in “Case studies on space solar power in Korea,” published on Space Solar Power and Wireless Transmission.

Solar panels are highly recyclable, but the use of thin plastic layers to encase solar cells can cause challenges in recycling valuable materials like silicon or silver effectively.

The National Renewable Energy Laboratory (NREL) has developed a proof of concept that helps cut the use of polymers by making direct glass-to-glass welds in solar cells.

The method makes use of femtosecond lasers, a type of infrared laser that focuses energy on a very short time scale with a single laser pulse. The laser creates hermetically sealed glass-on-glass welds. Femtosecond lasers are currently used in medical eye procedures like cataract surgery today.

The laser welds would eliminate the need for plastic laminates that make recycling more difficult. At the end of their useful life span, the modules made with laser welds can be shattered, and the glass and metal wires therein can be recycled and the silicon reused.

“Most recyclers will confirm that the polymers are the main issue in terms of inhibiting the process of recycling,” said David Young, senior scientist and group manager for the High-Efficiency Crystalline Photovoltaics group in the Chemistry and Nanoscience department at NREL.

NREL published the study in IEEE Journal of Photovoltaics. The authors said the laser is cell material agnostic, able to be used with silicon, perovskites, cadmium telluride, etc., because the heat from the highly focused laser is confined to a few millimeters. The researchers said the welds within the glass are essentially as durable as glass itself.

“As long as the glass doesn’t break, the weld is not going to break,” said Young. “However, not having the polymers between the sheets of glass requires welded modules to be much stiffer. Our paper showed that with proper mounting and a modification to the embossed features of the rolled glass, a welded module can be made stiff enough to pass static load testing.”

A different type of edge sealing using nanosecond lasers and a glass frit filler was tried in the past, but the welds proved too brittle for use in outdoor module designs. The femtosecond laser welds offer superior strength with hermetic sealing at a compelling cost, said NREL.

The research was conducted through the Durable Module Materials Consortium, which targets extending the useful life of solar panels to 50 years or beyond.

From pv magazine Germany

Exactly 70 years ago today, scientists at Bell Labs in New Jersey presented the first practical “solar battery” to the public. The New York Times reported at the time that “this invention could mark the beginning of a new era – the harnessing of the almost limitless solar energy for human civilization.”

However, it took several decades for this vision to become tangible. The global growth of PV has only really gained momentum in the last 10 years. While 1 GW of PV power was installed worldwide throughout 2004, by 2010 it was at 1 GW per month. Five years later, installation reached 1 GW per week and most recently, around 1 GW per day, according to Carsten Pfeiffer, head of strategy at Germany’s Bundesverband Neue Energiewirtschaft association, in a recent Twitter thread. “We will probably see an annual increase of 1 TW within this decade,” he stated.

U.S. scientists Daryl Chapin, Gerald Pearson and Calvin Fuller initially only had the task of developing a reliable energy source for remote telephone systems where conventional batteries had been ineffective. Solar cells made from the semiconductor material selenium had already been developed, but their efficiency was too low for useful applications.

Systematic, months-long development of a silicon solar cell produced the functioning prototype for the first usable solar module, which was presented on April 25, 1954. The efficiency at the time was only 6%. This initially increased slowly in the following decades. Only over the last two decades, due to the industrialization of PV production and accelerated technical progress, has this increased to around 25%, which is close to the physical limit established for silicon solar cells.

Even today, Bell Labs – which was then part of AT&T and now operates under Nokia Bell Labs – calls “the solar cell” one of its “greatest innovations.” The three scientists were posthumously honored for their invention in 2008 by being inducted into the US National Inventors Hall of Fame.

In 2004, the US Department of Energy’s National Renewable Energy Laboratory (NREL) published an article celebrating the cell’s 50th birthday.

Author: Thomas Seltmann

From pv magazine Global

NREL has updated its Best Research-Cell Efficiency Chart. The tool highlights the highest confirmed conversion efficiencies of research cells for a range of PV technologies.

“Everything up to the end of 2023 is included,” a spokesperson from the US Department of Energy’s research institute told pv magazine, noting the chart also includes important results achieved in the first quarter of this year. “The format of the chart will soon change to include hybrid tandems.”

The chart now includes the 33.9% world record efficiency achieved in November by Chinese manufacturer Longi for a perovskite-silicon tandem solar cell and the 27.09% efficiency achieved by the same company for a heterojunction back contact solar cell. Furthermore, it comprises the 23.64% efficiency achieved in March by US-based thin-film module maker First Solar for a solar cell based on copper, indium, gallium and diselenide (CIGS) technology.

With the interactive version of the chart, users can pull up decades of research data and compare custom charts that focus on specific technologies or time periods. They can find data on a cell’s current, voltage output, and fill factor, in addition to efficiency. The availability of those details will depend on the information in NREL’s records.

The highest research cell efficiency recorded in the chart is 47.6%, for a four-junction cell developed by Germany’s Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE).

From pv magazine Global

CSP is experiencing a remarkable resurgence and India unveiled a 50% allocation for CSP in its renewable energy tender for the first quarter of 2024.

Scaling up CSP will bridge the gap caused by intermittent-generation PV and wind projects to help power the world’s most populous country with reliable, affordable, continuous renewable energy.

Rajan Varshney, deputy managing director of the National Thermal Power Corporation, India’s largest state-owned utility company said recently, “Now is the right time for CSP … As PV and wind capacity increases, increasingly more and more coal-based power will be required to make it firm and to supply electricity when the sun is not there. So by increasing PV, we cannot avoid coal unless we install CSP plus storage in Gujarat and Rajasthan.”

CSP’s resurgence may surprise industry insiders who consider the technology obsolete after problems with large scale sites, notably in California and Arizona.

While previous installations were massive, complex, custom-engineered, and not replicable, my company, 247Solar, has obtained finance for a modular version that solves for these challenges.

Our version operates on superheated air at normal atmospheric pressure. It stores energy using simple materials, not molten salt, and it can be mass-produced in 400 kW units for economies of scale.

The model shows promise to greatly shorten project cycles and resume the dramatic CSP cost reductions achieved in its early years and which slowed as the older technology matured.

Demand

Around-the-clock power demand has been rising because of growth in emerging economies and is accelerating due to data centers, cryptocurrency, and artificial intelligence (AI). As we move to electrify with electric vehicles, heat pumps, and industrial heat, CSP emerges as a viable solution to address those needs and provide continuous power.

Grid operators continue to grapple with the variability of photovoltaic and wind energy. Wind, if it blows at night, can help balance daytime solar but wind is much more variable than sunshine and requires long-distance, high-voltage lines to get to market, which can add cost and time to wind farm deployment.

Even large doses of lithium-ion batteries – meant to handle morning and evening peak loads, as gas peaker plants did before them – are nowhere near enough to store the energy it would take to keep the grid powered through the night and during bad weather, as coal plants have. Batteries may also feature conflict minerals, unlike our thermal energy storage systems.

CSP’s levelized cost of energy (LCOE) has fallen dramatically, by almost 70% since 2010, offering longer and more economical energy storage than batteries.

Concentrated solar has returned to projects that will pair it with PV to extend power output into the night, reducing overall LCOE by harnessing synergies between the two technologies.

Pioneers

Some of the high-profile early efforts at CSP got many things right, such as Abengoa Solar’s Solana plant near Phoenix, launched in 2013, or BrightSource’s Ivanpah plant in California, the world’s largest solar thermal site at the time, also in 2013.

Initial CSP plants focused the sun’s heat on a single point, reaching temperatures above 530 degrees Celsius. Our system pushes that limit to around 1,000 degrees Celsius.

Those pioneer sites also stored energy for six- to 12-hour operation at night, aiming for more straightforward, cost-effective technology than polysilicon-based PV modules.

CSP is no longer just huge installations of pipes and mirrors in the desert or towers as high as a wind turbine, however.

We are seeing new interest in 247Solar’s smaller, simpler, more flexible application of this technology.

Our turbines generate electricity from nothing more than superheated air so they don’t require a phase change of the energy from heat to steam as other CSP systems do.

Sustainable

We store the extra heat in cheap, inert materials such as sand, iron slag, or ceramic pellets. This eliminates the need for corrosive, high-maintenance molten salt, along with its other chemical and physical challenges.

Our proprietary thermal batteries provide 18-plus hours of storage for on-demand, industrial-grade heat and electricity. They can produce power during bad weather and, when fully discharged, the generators can even run on green hydrogen, natural gas, or diesel. With a capacity factor of 85%, however, that would occur far less often than in a system of PV plus batteries with a 40% capacity factor.

Our turnkey solution, which we call 247Solar Plants, is modular and factory-built for rapid cost reduction through mass production and easy, quick, on-site assembly.

Each module has 400 kW of generation capacity with 120-foot towers – half the height of earlier versions of CSP. With fewer moving parts than conventional CSP, our solar thermal power plant is also easier to maintain in a hostile environment.

We hold more than 30 patents worldwide, including a blanket patent just obtained in India, for our entire CSP system; as well as our proprietary solar collectors; ultra-efficient Heat2Power turbines, that use ambient air pressure; and inexpensive thermal battery systems.

Hybrid

This hybrid approach leverages the strengths of CSP and photovoltaics to generate uninterrupted power 24/7, with PV providing cheap electricity during the day while CSP stores its excess energy as heat for use at night.

Other companies, such as Heliogen, BrightSource Energy, and Acciona, are also pushing the boundaries of CSP with advancements in AI-enabled systems, alternatives to the shortcomings of molten salt storage, and lower-cost parabolic trough technology.

Potential applications for CSP include on- or off-grid combined heat and power, microgrids, ultra-heat for heavy industry, green hydrogen, and green desalination, as well as baseload power 24/7/365 – critical in fast-growing economies such as India’s.

“Emerging technologies such as solar thermal and concentrated solar power are essential for India to meet its renewable energy targets,” said India’s New & Renewable Energy Secretary Bhupinder Singh Bhalla, at the opening of the International Conference on Solar Thermal Technologies in New Delhi, in February 2024.

CSP is unmatched, especially when integrated with photovoltaics, for 24/7 dispatchability of flexible, dependable, and resilient zero-carbon power to meet the energy demands of tomorrow.

Bruce Anderson is a visionary in the solar industry for four decades, is founder and chief executive officer of 247Solar, which is commercializing a concentrating solar technology invented at MIT and which runs on superheated compressed air instead of steam. His career spans seven company ventures, a “New York Times” bestseller, and the American Solar Energy Society’s Lifetime Solar Contribution Award.

From pv magazine Global

Researchers at Lehigh University in the United States developed a new thin-film solar cell absorber material that reportedly features an average photovoltaic absorption of 80% and an external quantum efficiency (EQE) of 190%.

Th EQE is the ratio of the number of electrons collected by the solar cell to the number of photons that hit it. It defines how well a solar cell converts photons into electrical current. “In traditional solar cells, the maximum EQE is 100%, representing the generation and collection of one electron for each photon absorbed from sunlight,” the research’s lead author Chinedu Ekuma said in a statement.

In the paper “Chemically tuned intermediate band states in atomically thin Cu_xGeSe/SnS quantum material for photovoltaic applications,” published in ScienceAdvance, the academics explained that the new quantum material may be an ideal match for intermediate band solar cells (IBSCs).

These devices are believed to have the potential to exceed the Shockley-Queisser limit – the maximum theoretical efficiency that a solar cell with a single p-n junction can reach. It is calculated by examining the amount of electrical energy that is extracted per incident photon.

“The material’s efficiency leap is attributable largely to its distinctive ‘intermediate band states,’ specific energy levels that are positioned within the material’s electronic structure in a way that makes them ideal for solar energy conversion,” the scientists explained. “These states have energy levels within the optimal subband gaps—energy ranges where the material can efficiently absorb sunlight and produce charge carriers.”

The new material is a 2D two-dimensional Van der Waals (vdW) material, which means it features a crystalline planar configuration held together by ionic bonds. It consists of an heterostructure combining germanium (Ge), selenium (Se), and tin sulfide (Sns) with atoms of zerovalent copper (Cu) being inserted between the material’s layers.

The Cu_xGeSe/SnS material features an intermediate energy bandgap ranging from 0.78 eV and 1.26 eV. With it, the group designed and modeled a thin-film solar cell with the proposed material as the active layer.

The device was assumed to be based on an indium tin oxide (ITO) substrate, an electron transport layer (ETL) based on zinc oxide (ZnO), Cu_xGeSe/SnS absorber, and a gold (Au) metal contact. “In our design, atomically thin GeSe and SnS are vertically stacked, facilitating the easy integration of the hybrid structures through van der Waals interactions,” the research team specified.

The simulation showed that the cell EQE may span from 110% to 190%. The researchers also found that by gauging the absorber’s thickness the cell optical activity increases in wavelengths ranging from 600 to 1200 nm.

“The rapid response and enhanced efficiency in Cu-intercalated samples, strongly indicate the potential of Cu-intercalated GeSe/SnS as a quantum material for use in advanced photovoltaic applications, offering an avenues for efficiency improvements in solar energy conversion,” they concluded.

Looking forward, the research group said new research is required to identify a practical way to embed the novel material in real solar cells. However, they also noted that the experimental techniques used to create these materials are already “highly advanced.”

From pv magazine Global

A group of researchers in Germany has developed a comprehensive optoelectrical simulation model for triple-junction solar cells based on subcells relying on perovskite, perovskite, and crystalline silicon, respectively.

The model is intended to define an efficiency roadmap for improving the optical properties of these solar cells within realistic boundary conditions. “The roadmap includes the adaption of the perovskite absorber thicknesses, modifying bandgaps, employing a fully textured cell, and optimizing the thicknesses of the interlayers between the absorbers,” the scientists explained. “We calculate the respective photocurrent of each step and compare it against the theoretical limit.”

For their modeling, the academics chose the Sentaurus TCAD, which is a multidimensional simulator capable of simulating the electrical, thermal, and optical characteristics of silicon-based devices. It is also used to simulate the optoelectronic characteristics of semiconductor devices, such as image sensors and PV cells.

“This tool has already demonstrated its capability in accurately describing the optical properties of perovskite tandem solar cells,” they said, referring to previous, similar research they conducted on perovskite-silicon tandem cells. In this work, they concluded that the practical power conversion efficiency potential of perovskite-silicon tandem devices may reach up to 39.5%.

In their most recent work, the researchers initially assumed the triple junction cell to be based on a bottom silicon heterojunction cell with an indium tin oxide (ITO) layer and a silver (Ag) metal contact, a middle perovskite cell with an energy bandgap of 1.57 eV, and a top perovskite cell with a bandgap of 1.84 eV.

In the optimization process, their efforts were directed to increase the photocurrent of all three cells. They initially varied the thicknesses of the three absorbers and then they adjusted the perovskites bandgaps. Moreover, they applied a textured front side to mitigate reflection losses and used thinner interlayers. “Adapting the perovskite absorber thicknesses is rather simple but has the potential to achieve current matching between the top and middle cell,” the group emphasized. “This way the current can be improved significantly.”

The scientists also gauged the thickness of the anti-reflective coating based on magnesium fluoride (MgF2) by reducing its thickness from 130 nm to 90 nm. They also initially increased the thickness of the middle cell’s perovskite absorber, which they said reduces photon absorption in the silicon subcell, but offers improved absorption in the top and middle devices, thus increasing photocurrent at the triple-junction cell level.

The simulation showed that the best cell configuration may potentially achieve a power conversion efficiency of 44.3%, an open-circuit voltage of 3480 mV, a short-circuit density of 14.1 mA cm⁻², and a fill factor of 90.1%. This was achieved with a middle perovskite cell with an energy bandgap of 1.46 eV and a top perovskite cell with a bandgap of 1.97 eV.

“On the other hand, we showed that the range of the top-cell bandgap could be chosen between 1.8 and 2.0 eV, depending on the top cell thickness varying between 200 and 800 nm, respectively, for which each a bandgap/thickness tuple exists to achieve global current matching,” the scientists stressed. “Nevertheless, we raised awareness for choosing thicker perovskite layers with higher bandgap to unleash the full open-circuit voltage potential of the top cell.”

Their findings are available in the paper “Optoelectrical Modeling of Perovskite/Perovskite/Silicon Triple-Junction Solar Cells: Toward the Practical Efficiency Potential,” which was recently published in RRL Solar. The research team was formed by scientists from the University of Freiburg and Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE).

In 2020 the Department of Energy (DOE) launched the Energy Storage Grand Challenge, with a mission to sustain U.S. global leadership in energy storage. The Grand Challenge built on the $158 million Advanced Energy Storage Initiative in the Fiscal Year 2020 budget request, with an aim of accelerating the development, commercialization and use of next-generation energy storage technologies. The recipients were named at the Long-Duration Energy Storage Council Summit:

• New Lab, LLC
  • Project Title: Enabling high-capacity zinc utilization through electrode and electrolyte fundamentals
  • Federal share: $4,992,570
• Battery Council International 
  • Project Title: Consortium for Lead Battery Leadership in LDES
  • Federal share: $4,972,746
• Clean Tech Strategies LLC
  • Project title: Pre-Competitive Research & Development to Accelerate the Maturation of Flow Battery Technologies into Cost-Effective Long Duration Energy Storage
  • Federal share: $5,000,000

The Office of Electricity selected these organizations for their innovative approaches to overcoming barriers in research and development of domestic energy storage.

Awards of up to $5 million each are given for projects that the Office of Electricity sees as bringing together technology stakeholders and research institutions to solve one or more pre-competitive R&D technical challenge.

Projects must enable a long-duration capable (10+ hours) energy storage technology with a pathway to $0.05/ kWh levelized cost of storage (LCOS) by 2030, the goal of the Long Duration Storage Shot.

With the current administration’s goal of net-zero emissions by 2050, long-duration grid-scale energy storage is necessary to stabilize the grid. These awards support domestic projects that will advance zinc, lead and flow battery technologies, all of which are expected to build on the Inflation Reduction Act’s domestic production incentives for energy storage.

The awardees are focused on non-lithium technologies, which the Office of Electricity sees as helping create a “future diversified and secure energy storage supply chain that reduces dependence on critical materials”.

“These funding opportunities help propel the future of energy storage and deliver cost-effective solutions for our nation’s electricity needs” said Gene Rodrigues, assistant secretary for electricity. “Energy storage bolsters system reliability and enables every American to benefit from abundant and affordable clean energy. These consortia will accelerate the race to achieve the Long Duration Storage Shot, fulfilling the promise of next-generation energy storage technologies for the benefit of the American people.”

The Energy Storage Grand Challenge sets the following goals for the U.S. to reach by 2030:

1. Technology Development: Establish ambitious, achievable performance goals, and a comprehensive R&D portfolio to achieve them;
2. Technology Transfer: Accelerate the technology pipeline from research to system design to private sector adoption through rigorous system evaluation, performance validation, siting tools, and targeted collaborations;
3. Policy and Valuation: Develop best-in-class models, data, and analysis to inform the most effective value proposition and use cases for storage technologies;
4. Manufacturing and Supply Chain: Design new technologies to strengthen U.S. manufacturing and recyclability, and to reduce dependence on foreign sources of critical materials; and
5. Workforce: Train the next generation of American workers to meet the needs of the 21st century electric grid and energy storage value chain.

Massachusetts-based Alsym Energy announced it has secured $78 million in Series C funding, with funds provided by Tata Limited, General Catalyst, Thombest and Drads Capital. The funds are expected to help the company expand prototyping and pilot lines for its batteries.

Alsym develops a metal-oxide battery that uses similar chemical mechanisms as lithium-ion batteries, with a working ion shuttling between anode and cathode materials. The company said it uses inherently non-flammable materials and uses a water-based electrolyte. Battery fires are a known risk to conventional lithium-ion batteries.

The company said the chemistry is dendrite-free, which makes it immune to conditions that cause thermal runaway, the main cause of fire in lithium batteries.

The startup venture has disclosed that its electrode is manganese oxide, but other critical details have not been shared. It currently provides prototype samples, but no finished product is available for purchase.

(Read: “Can anything topple lithium-ion?”)

Alsym said its batteries can serve grid-scale use cases, charging and discharging intermittent solar and wind generation. The batteries can discharge between 4 to 110 hours.

The company’s first product, called Alsym Green, is targeting 3.4 MWh per 40 foot container, which it said is higher than other non-lithium battery alternatives available on the market today.

Alsym said its batteries will serve a wide range of other use cases including home energy storage, marine and maritime battery storage, small vehicles and passenger electric vehicles.

Despite this broad vision for its prototype stage battery, Alsym’s management said there is no one-size-fits-all chemistry for battery use cases.

“As the clean energy transition accelerates, it’s becoming more apparent that a single battery technology is not ideal for every use case, and that more options are needed to help address the challenges of a changing climate,” said Mukesh Chatter, chief executive officer and co-founder of Alsym Energy.

The company noted a non-lithium ion based battery may be desirable in a global market with competitive and constrained lithium supply chains.

From pv magazine Global

A survey of 110 experts identified by the Transport and PV group at the International Energy Agency’s Photovoltaic Power Systems Programme (IEA-PVPS) Task 17 (T17) reveals a set of technical requirements or areas seen as important for the adoption of vehicle-integrated photovoltaics (VIPV) with a focus on passenger vehicles.

The study was conducted by the Netherlands Organisation for Applied Scientific Research (TNO) and includes experts’ views on what users may be willing to give up in terms of PV yield to achieve superior vehicle aesthetics.

When it comes to the choice of cell technology for VIPV, crystalline silicon (c-Si) is dominant with a clear preference for back contact technology and no visible metal. However, by 2030 survey respondents expect tandem and thin film technology to grow.

“The desire for minimal visibility of metal on the front side of cells, coupled with a preference for glass on roof components and polymer on other surfaces, indicates a strong aesthetic consideration in VIPV design,” said the researchers.

The study considered the variety of cell technologies available in prototype and commercial VIPV passenger cars. For example, startups Lightyear and Sono Motors used c-Si, while Japanese automakers Toyota and Nissan used Sharp’s III-V compound solar technology, and Germany’s Flixbus and European joint venture Volvo-Renault have used CIGS

Several system features, including color, charging frequency, and cost, were ranked with the most important being efficiency, additional mileage per year, and vehicle range extension. “The report underscores the paramount importance of these factors, alongside the significant benefit of reducing the need for charging,” noted the researchers.

Looking at efficiency based on an available area of 3 m2 area, the respondents agreed on the minimum power conversion efficiency of at least 20% to 22%, with power output ranging from 600 W to 660 W, while a large group, 29%,  said it should be greater than 25%, with power output reaching 750 W.

Module lifetime of at least 10 to 15 years was indicated, along with the need for repair concepts that include spot repairs for visible damage and full-body replacement parts for performance failures.

The cost of VIPV systems, manufacturing and installation costs, are expected to fall by as much as 60% by 2030, according to the survey results. The largest technical bottleneck to lower costs is the complexity of manufacturing.

Asked about surprising results, TNO scientist and co-leader of the task group, Anna J. Carr, told pv magazine, “Probably the amount of performance that people were willing to sacrifice to get the colors they wanted. Among the respondents who said more color choice, than black or dark blue, is required an average performance loss of 24.2% was indicated to be acceptable.”

Around 62% of respondents came from PV research, while 13% came from PV cell or module manufacturing, 9% from automotive manufacturing, and 8% from automotive research. The majority are from Europe, with just 20% from Asia and a small percentage from North America.

“The reason that so many of the respondents were European is that the invitations to take part in the survey went out to the companies and researchers that we knew who were already working on the topic. And it represents the membership mix of T17,” said Carr.

Looking ahead, the researchers recommended adding more industry professionals to the survey group to be able to develop a better understanding of VIPV preferences and requirements. In addition, the group is likely to expand the focus and look at VIPV in heavy-duty and commercial vehicles, according to Carr.

The objective of Task 17 of the IEA PVPS is to deploy PV in the transport sector, contributing to reducing CO2 emissions of the sector and enhancing PV market expansions.

NREL has created a cost-estimation tool that evaluates the potential construction and labour costs associated with closed-loop PSH plants in the United States.

The tool allows operators to select from a range of system characteristics, accounting for factors such as local geology, labor rates and inflation. NREL said it could help grid planners to provide an accurate picture of how many PSH facilities could reasonably be built over the coming decades and how they could work together with batteries.

“Pumped storage hydropower is maybe the most promising energy storage solution we have to achieve the huge ramp up needed to achieve a clean electricity sector,” said NREL researcher Daniel Inman.

PSH is the biggest source of grid-scale energy storage capacity in the United States, accounting for around 96% in 2022, according to the US Department of Energy. But NREL said few new pumped storage hydropower facilities have been built since the 1970s, partly due to high upfront costs.

Closed-loop PSH systems, which are separated from naturally flowing waterways, are the favored option today as they are more environmentally friendly. NREL said that due to gaps in the construction of pumped storage facilities, it has been difficult to predict how much closed-loop facilities might cost.

“This tool allows potential project developers to get a ballpark figure for what a particular facility might cost,” Inman explained. “And a more realistic cost estimation would allow us to develop capacity expansion modeling results that are more realistic.”

Last week, NREL released a high-resolution solar data set covering Africa, Eastern Europe and the Middle East on its Renewable Energy Data Explorer tool.

In February, researchers from Australian National University published a global atlas for potential PSH sites in former mining areas.

Researchers from the University of Texas at Austin are researching methods to produce hydrogen fuel from iron-rich rocks in an emissions-free process. 

The university received a $1.7 million grant from the Department of Energy Advanced Research Projects Agency-Energy (ARPA-E). The university is partnering with the University of Wyoming’s School of Energy Resources on the project. 

Today, most hydrogen in the U.S. is produced by burning natural gas. This process, sometimes referred to as “blue hydrogen” production, remains a contributor to greenhouse gas emissions alongside traditional fossil fuel use. The industry has also begun to embrace “green hydrogen,” a process that makes use of electricity from solar and wind generation sources. 

Now, there may be a new entrant in hydrogen in the form of “geologic hydrogen.” 

The research team at UT Austin is exploring the use of different natural catalysts to produce hydrogen gas from iron-rich rocks, mimicking a natural process called “serpentinization.” 

In nature, iron-rich rocks release hydrogen as a byproduct of the serpentinization process, a low-temperature rock metamorphosis. It is particularly common at the sea floor at tectonic plate boundaries. Natural catalysts like nickel and platinum group elements are being explored as catalysts to induce this process.

“Natural accumulations of geologic hydrogen are being found all over the world, but in most cases they are small and not economical, although exploration continues,” said Esti Ukar, a research associate professor, UT Austin. 

Ukar said the research will test generating larger volumes of hydrogen from iron-rich rocks that would normally take several million years to naturally occur. The research is a first-of-its-kind project to create a process to produce geological hydrogen at an industrial scale.

Researchers at Colorado University Boulder are researching serpentinization in hydrogen production as well. The team is performing accelerated underground testing to better our understanding of the chemical reactions that produce hydrogen naturally.

“If we can accelerate these reactions underground, we can turn rocks into a clean and abundant energy resource,” said Eric Ellison, research scientist at CU Boulder.

A 2022 report from the U.S. Geological Survey (USGS) suggested there may be enough naturally occurring geologic hydrogen to meet global demand for generations, potentially offering a rapid replacement for harmful carbon-emitting fossil fuels.

“Using a conservative range of input values, the model predicts a mean volume of hydrogen that could supply the projected global hydrogen demand for thousands of years,” said USGS researcher Geoffrey Ellis. “We have to be very careful in interpreting this number, though. Based on what we know about the distribution of petroleum and other gases in the subsurface, most of this hydrogen is probably inaccessible.”   

Ellis research showed that much of this hydrogen supply is too deeply buried or too far offshore to be economically recovered.

And while USGS said even a fraction of the Earth’s geological hydrogen resources could serve global liquid fuel demand for hundreds of years, relying on fuels that require natural processes that take millions of years may pose its own challenges. Extractive natural fuels are not part of a long-term circular economy, a vision pursued by the National Renewable Energy Laboratory (NREL).

“Decarbonization of the U.S. economy will require rapid deployment of clean energy technologies,” said NREL. “This will demand large amounts of materials—including scarce, critical materials. Ensuring these materials are available in the necessary quantities and at their highest value and function will necessitate a robust circular economy for energy materials.”

An international team of researchers announced an important achievement on the path to commercializing perovskite solar cells. Perovskite, a semiconducting material, is the focus of research around the globe due to its potential to convert more solar power to electricity than the commonly used silicon, and at lower cost.

There are drawbacks, however, in the production of perovskite solar. One of them is that the coating process must take place inside a chamber filled with non-reactive gas because otherwise the perovskites react with oxygen, thus decreasing performance.

A new paper published in the journal Nature Energy describes the work conducted by Jixian Xu and his team at the National Synchrotron Radiation Laboratory, University of Science and Technology of China. The team found that adding dimethylammonium formate (DMAFo) to the perovskite solution before coating could prevent the materials from oxidizing. This discovery enables coating to take in ambient air instead of having to be inside a box.

Michael McGehee, a professor in the Department of Chemical and Biological Engineering and fellow with Colorado University Boulder’s Renewable & Sustainable Energy Institute, interpreted the results and helped with writing the paper. He told pv magazine USA that this was the first time DMAFo had been used in perovskite research and said it’s helpful because it is a reducing agent that prevents iodide from oxidizing. As he described it, the DMAFo was added into the perovskite precursor solution. “It protects the iodide in that solution, making it possible to make the cells in air and greatly extending the shelf life of the precursor solution,” McGehee said.

McGehee acknowledged that coating inside a box is acceptable during the research phase, “but when you start coating large pieces of glass, it gets harder and harder to do this in a nitrogen filled box,” he said.

The results show that DMAFo perovskite cells can achieve an efficiency of nearly 25% on their own, comparable to the current efficiency record for perovskite cells of 26%.

The additive also improved the cells’ stability, which McGehee noted is important for the transition to clean energy.

An issue with perovskite solar compared to silicon is that they can degrade much faster. The study showed that the perovskite cell made with DMAFo retained 90% of its efficiency after being exposed to LED light that mimicked sunlight for 700 hours. In contrast, cells made in the air without DMAFo degraded quickly after only 300 hours.

McGehee noted that longer tests are needed because there are 8,000 hours in one year. “It’s too early to say that they are as stable as silicon panels, but we’re on a good trajectory toward that,” he said.

The next step for the team is to develop tandem cells with a real-world efficiency of over 30% that are as equally stable as silicon panels over a 25-year period.

After a decade of research in perovskites, engineers have built perovskite cells that are as efficient as silicon cells, which were invented 70 years ago, McGehee said. “We are taking perovskites to the finish line.  If tandems work out well, they certainly have the potential to dominate the market and become the next generation of solar cells,” he said.

From pv magazine Global

Thornova Solar, the US unit of Chinese PV manufacturer Sunova Solar, has launched a new bifacial TOPCon PV module for applications in large scale solar projects.

The TS-BWT66-G12 dual-glass module has a size of 2,384 mm x 1,303 mm x 35 mm and weighs 38.5 kg. It features a power conversion efficiency spanning from 22.4% to 23.2% and a temperature coefficient of -0.29% per C.

Its power output ranges from 695 W to 720. The open-circuit voltage is between 47.23 V and 47.98 V and the short-circuit current is of 18.68 A to 18.79 A. It can operate with a system voltage of 1,500 V and temperatures ranging from -40 C to 85 C.

The new product also features a transparent white mesh backsheet, 2.0 mm heat-strengthened glass, and an anti-reflective coating. It comes with a 15-year product warranty and a 30-year performance warranty.

“Annual linear degradation over 30 years is 0.4%, with a maximum degradation in the first year of 1.0%,” the manufacturer said in a statement.

Thornova Solar is planning to build a solar cell and module factory at an unspecified location in the United States in 2025.

“We plan to produce both cells and modules in the United States in 2025, enabling buyers to take full advantage of US tax credits for solar modules with domestic content,” Thornova CEO, William Sheng, said. “With the rapid growth in solar power generation in the U.S., we aim to provide a strong, reliable U.S.-based supply of modules that are optimally designed for utility-scale projects.”

Sunova Solar currently operates three manufacturing factories in China and Vietnam. The company said that as of December 2023, it had shipped more than 4 GW of cumulative modules throughout the world.

Singapore’s Maxeon has announced that it has achieved an aperture module conversion efficiency of 24.9% for a full-scale Maxeon 7 PV panel.

The US Department of Energy’s National Renewable Energy Laboratory (NREL) confirmed the result. The Maxeon 7 module is based on interdigitated back contact (IBC) technology.

For the same panel, Maxeon achieved a power conversion efficiency of 24.7% in June.

“Maxeon 7 cells feature a unique and patented design to mitigate hotspot risk from cell cracking and heat buildup under shaded conditions.” the manufacturer said in a statement. “This results in increased reliability and power output, as supported by the Company’s 40-year warranty.”

The manufacturer hosts a Maxeon 7 pilot assembly line in the Philippines.

From pv magazine print edition 3/24

Sodium ion batteries are undergoing a critical period of commercialization as industries from automotive to energy storage bet big on the technology. Established battery manufacturers and newcomers are jostling to get from lab to fab with a viable alternative to lithium ion. With the latter standard for electric mobility and stationary storage, new technology must offer proven advantages. Sodium ion looks well placed, with superior safety, raw material costs, and environmental credentials.

Sodium ion devices do not need critical materials, relying on abundant sodium instead of lithium, and no cobalt or nickel. As lithium ion prices rose in 2022, amid predictions of material shortages, sodium ion was tipped as a rival and interest remains strong, even as lithium ion prices have started to fall again.

“We are currently tracking 335.4 GWh of sodium ion cell production capacity out to 2030, highlighting that there is still considerable commitment to the technology,” said Evan Hartley, senior analyst at Benchmark Mineral Intelligence.

In May 2023, the London-based consultant had tracked 150 GWh to 2030.

Cheaper

Sodium ion cells, produced at scale, could be 20% to 30% cheaper than lithium ferro/iron-phosphate (LFP), the dominant stationary storage battery technology, primarily thanks to abundant sodium and low extraction and purification costs. Sodium ion batteries can use aluminum for the anode current collector instead of copper – used in lithium ion – further reducing costs and supply chain risks. Those savings are still potential, however.

“Before sodium ion batteries can challenge existing lead acid and lithium iron phosphate batteries, industry players will need to reduce the technology’s cost by improving technical performance, establishing supply chains, and achieving economies of scale,” said Shazan Siddiqi, senior technology analyst at United Kingdom-based market research company IDTechEx. “Na-ion’s cost advantage is only achievable when the scale of production reaches a manufacturing scale comparable to lithium ion battery cells. Also, a further price drop of lithium carbonate could reduce the price advantage sodium offers.”

Sodium ion is unlikely to supplant lithium ion in applications prioritizing high performance, and will instead be used for stationary storage and micro electric vehicles. S&P Global analysts expect lithium ion to supply 80% of the battery market by 2030, with 90% of those devices based on LFP. Sodium ion could make up 10% of the market.

Right choices

Researchers have considered sodium ion since the mid-20th century and recent developments include improvements in storage capacity and device life cycle, as well as new anode and cathode materials. Sodium ions are bulkier than lithium counterparts, so sodium ion cells have lower voltage as well as lower gravimetric and volumetric energy density.

Sodium ion gravimetric energy density is currently around 130 Wh/kg to 160 Wh/kg, but is expected to top 200 Wh/kg in future, above the theoretical limit for LFP devices. In power density terms, however, sodium ion batteries could have 1 kW/kg, higher than nickel-manganese-cobalt’s (NMC) 340W/kg to 420 W/kg and LFP’s 175 W/kg to 425 W/kg.

While a sodium ion device life of 100 to 1,000 cycles is lower than LFP, Indian developer KPIT has reported a lifespan with 80% capacity retention for 6,000 cycles – dependent on cell chemistry – comparable to lithium ion devices.

“There is still no single winning chemistry within sodium ion batteries,” said IDTechEx’s Siddiqi. “Lots of R&D efforts are being undertaken to find the perfect anode/cathode active material that allows scalability beyond the lab stage.”

Referring to United States-based safety science organization Underwriter Laboratories, Siddiqi added that “UL standardization for sodium ion cells is, therefore, still a while away and this makes OEMs [original equipment manufacturers] hesitant to commit to such a technology.”

Prussian white, polyanion, and layered oxide are cathode candidates featuring cheaper materials than lithium ion counterparts. The former, used by Northvolt and CATL, is widely available and cheap but has relatively low volumetric energy density. United Kingdom-based company Faradion uses layered oxide, which promises higher energy density but is plagued by capacity fade over time. France’s Tiamat uses polyanion, which is more stable but features toxic vanadium.

“The majority of cell producers planning sodium ion battery capacity will be using layered oxide cathode technology,” said Benchmark’s Hartly. “In fact, 71% of the [cell] pipeline is layered oxide. Similarly, 90.8% of the sodium ion cathode pipeline is layered oxide.”

Whereas cathodes are the key cost driver for lithium ion, the anode is the most expensive component in sodium ion batteries. Hard carbon is the standard choice for sodium ion anodes but production capacity lags behind that of sodium ion cells, ramping up prices. Hard carbon materials have recently been derived from diverse precursors such as animal waste, sewage sludge, glucose, cellulose, wood, coal and petroleum derivatives. Synthetic graphite, a common lithium ion anode material, relies almost exclusively on the latter two precursors. With its developing supply chain, hard carbon is more costly than graphite and represents one of the key hurdles in sodium ion cell production.

Partially mitigating higher costs, sodium ion batteries exhibit better temperature tolerance, particularly in sub zero conditions. They are safer than lithium ion, as they can be discharged to zero volts, reducing risk during transportation and disposal. Lithium ion batteries are typically stored at around 30% charge. Sodium ion has less fire risk, as its electrolytes have a higher flashpoint – the minimum temperature at which a chemical can vaporize to form an ignitable mixture with air. With both chemistries featuring similar structure and working principles, sodium ion can often be dropped in to lithium ion production lines and equipment.

In fact, the world’s leading battery maker CATL is integrating sodium ion into its lithium ion infrastructure and products. Its first sodium ion battery, released in 2021, had an energy density of 160 Wh/kg, with a promised 200 Wh/kg in the future. In 2023, CATL said Chinese automaker Chery would be the first to use its sodium ion batteries. CATL told pv magazine late in 2023 that it has developed a basic industry chain for sodium ion batteries and established mass production. Production scale and shipments will depend on customer project implementation, said CATL, adding that more needs to be done for the large scale commercial rollout of sodium ion. “We hope that the whole industry will work together to promote the development of sodium ion batteries,” said the battery maker.

Charge to sodium

In January 2024, China’s biggest carmaker and second-biggest battery supplier, BYD, said it had started construction of a CNY 10 billion ($1.4 billion), 30 GWh per year sodium ion battery factory. The output will power “micromobility” devices. HiNa, spun out of the Chinese Academy of Sciences, in December 2022 had commissioned a gigawatt-hour-scale sodium ion battery production line and announced a Na-ion battery product range and electric car prototype.

European battery maker Northvolt unveiled 160 Wh/kg-validated sodium ion battery cells in November 2023. Developed with Altris – spun out of Uppsala University, in Sweden – the technology will be used in the company’ next-generation energy storage device. Northvolt’s current offering is based on NMC chemistry. At the launch, Wilhelm Löwenhielm, Northvolt senior director of business development for energy storage systems, said the company wants a battery that is competitive with LFP at scale. “Over time, the technology is expected to surpass LFP significantly in terms of cost-competitiveness,” he said.

Northvolt wants a “plug-and-play” battery for fast market entry and scale-up. “Key activities for bringing this particular technology to market are scaling the supply chain for battery-grade materials, which Northvolt is currently doing, together with partners,” said Löwenhielm.

Smaller players are also doing their bit to bring sodium ion technology to commercialization. Faradion, which was acquired by Indian conglomerate Reliance Industries in 2021, says it is now transferring its next-generation cell design to production. “We have developed a new cell technology and footprint with 20% higher energy density, and increased cycle-life by a third compared to our previous cell design,” said Faradion Chief Executive Officer (CEO) James Quinn.

The company’s first-generation cells demonstrated an energy density of 160 Wh/kg. In 2022, Quinn said that Reliance’s plan was to build a double-digit-gigawatt sodium ion factory in India. For now, it seems that those plans are still in place. In August 2023, Reliance Chairman Mukesh Ambani told the company’s annual shareholder meeting that the business is “focused on fast-track commercialization of our sodium ion battery technology … We will build on our technology leadership by industrializing sodium ion cell production at a megawatt level by 2025 and rapidly build up to gigascale thereafter,” he said.

Production

Startup Tiamat has moved forward on its plans to start construction of a 5 GWh production plant in France’s Hauts-de-France region. In January 2024, it raised €30 million ($32.4 million) in equity and debt financing and said that it expects to complete the financing of its industrial project in the coming months, bringing the total financing to around €150 million. The company, a spinoff from the French National Centre for Scientific Research, will initially manufacture sodium ion cells for power tools and stationary storage applications in its factory, “to fulfill the first orders that have already been received.” It will later target scaled-up production of second-generation products for battery electric vehicle applications.

In the United States, industry players are also ramping up their commercialization efforts. In January 2024, Acculon Energy announced series production of its sodium ion battery modules and packs for mobility and stationary energy storage applications and unveiled plans to scale its production to 2 GWh by mid-2024. Meanwhile, Natron Energy, a spinoff out of Stanford University, intended to start mass-producing its sodium ion batteries in 2023. Its goal was to make 600 MW of sodium ion cells at battery producer Clarios International’s exiting lithium ion Meadowbrook facility, in Michigan. Updates on progress have been limited, however.

Funding

In October 2023, Peak Energy emerged with $10 million in funding and a management team comprising ex-Northvolt, Enovix, Tesla, and SunPower executives. The company said it will initially import battery cells and that was not expected to change until early 2028. “You need around a billion dollars for a small scale gigawatt factory – think less than 10 GW,” Peak Energy CEO Landon Mossburg said at the launch. “So the fastest way to get to market is to build a system with cells available from a third party, and China is the only place building capacity to ship enough cells.” Eventually, the company hopes to qualify for domestic content credits under the US Inflation Reduction Act.

Some suppliers, such as India’s KPIT, have entered the space without any production plans. The automotive software and engineering solutions business unveiled its sodium ion battery technology in December 2023 and embarked on a search for manufacturing partners. Ravi Pandit, chairman of KPIT, said that the company has developed multiple variants with energy density ranging from 100 Wh/kg to 170 Wh/kg, and potentially reaching 220 Wh/kg.

“When we started work on sodium ion batteries, the initial expectation of energy density was quite low,” he said. “But over the last eight years the energy density has been going up because of the developments that we and other companies have been carrying out.” Others are on the lookout for supply partnerships. Last year, Finnish technology group Wärtsilä – one of the world’s leading battery energy storage system integrators – said that it was seeking potential partnerships or acquisitions in the field. At the time, it was moving toward testing the technology in its research facilities. “Our team remains committed to pursuing new opportunities in terms of diversifying energy storage technologies, such as incorporating sodium ion batteries into our future stationary energy storage solutions,” said Amy Liu, director of strategic solutions development at Wärtsilä Energy Storage and Optimization, in February 2024.

Nearshoring opportunity

Following many mass-production announcements, sodium ion batteries are now at the make-or-break point and investor interest will determine the technology’s fate. IDTechEx’s market analysis, carried out in November 2023, suggests anticipated growth of at least 40 GWh by 2030, with an additional 100 GWh of manufacturing capacity hinging on the market’s success by 2025.

“These projections assume an impending boom in the [sodium ion battery] industry, which is dependent upon commercial commitment within the next few years,” said Siddiqi.

Sodium ion could offer yet another opportunity to near-shore clean energy supply chains, with the required raw materials so readily available across the globe. It appears that train has already left the station, however.

“As with the early stages of the lithium ion battery market, the main bottleneck for the global industry will be the dominance of China,” said Benchmark’s Hartley. “As of 2023, 99.4% of sodium ion cell capacity was based in China and this figure is only forecast to fall to 90.6% by 2030. As policy in Europe and North America seeks to shift lithium ion battery supply chains away from China, due to the reliance on its domestic production, so too will a shift be needed in the sodium ion market to create localized supply chains.”

From pv magazine print edition 3/24

Innovation at material, cell, and system level has been just as important in lithium ion’s leap forward as supply chain development. Stationary energy storage cell design is trending toward large-format prismatic cells thanks to lithium ferro-phosphate (LFP) battery chemistry. Lower costs, a longer cycle life, and better safety have seen LFP batteries eat into nickel-manganese-cobalt (NMC) market share since 2020. The energy density and charge rate offered by NMC devices has instead seen them favored for mobility uses.

New materials

Both offer room for development. Reducing cobalt and raising nickel content in NMC batteries offers lower costs and better energy density. LFP energy density can be improved by replacing some iron cathode material with manganese – for an LMFP cathode. This emerging technology shows great promise, as it provides roughly 15% to 20% more energy density, or up to 230 Wh/kg, while maintaining the same level of cost and safety as LFP batteries. Financial services firm Ernst & Young calculates that the costs of LMFP batteries are about 21% higher than that of LFP devices on a dollars-per-kilogram basis. Considering their higher energy density, however, the cost per watt-hour is 5% lower, making them much more economical.

Although LMFP batteries offer higher voltage and energy density than LFP, there are trade-offs. “There are issues with lower power capability and lower cycle life which arise from the lower electrical conductivity of LMFP compared to LFP, which limits the power capability; and the dissolution of the manganese into the electrolyte over cycling, which limits cycle life,” said John-Joseph Marie, energy storage analyst at British research body The Faraday Institution. As a result, Marie doesn’t see LMFP replacing LFP for short-duration storage. “If the issue of cycle life could be solved, LMFP could be a cost-efficient technology for longer storage durations, e.g. four to eight hours,” he said.

Moves toward mass production of LMFP batteries are picking up pace, though – especially in China. CATL, Eve, BYD, and Gotion – as well as South Korea’s Samsung SDI and United States-based Mitra Chem – are now at various stages of commercialization and are producing this technology. In mid 2023, Gotion High-Tech set a precedent for developing NMC-free batteries with a range that reached 1,000 km with the launch of its L600 Astroinno battery cell and pack, featuring LMFP chemistry. The Chinese manufacturer said its new battery technology, which has undergone a research period of 10 years, is scheduled to begin mass production in 2024.

On the anode side, graphite remains the go-to material with efforts made to boost its lithium-holding capacity by adding a small amount of silicon. The addition of silicon is an attractive proposition, as it would allow for almost 10 times more capacity, due to its theoretical capacity of 3,600 milliampere-hours per gram (mAh/g), compared to graphite’s maximum of 372 mAh/g. In 2023, Tesla reportedly added up to 5% of silicon to its graphite anodes via intermetallic alloying. Startups are even more bullish on the technology, with a few of them proposing 100% silicon anodes.

The advantage on the cost side is also pronounced. “Silicon anodes, including silicon composite anodes and pure silicon anodes, are expected to be cheaper to produce on a dollar-per-kilowatt-hour basis than the incumbent graphite anode technology, thanks to their much higher capacity,” said Marie.

London-based consultants Rho Motion have modeled the cost pathway for lithium ion cells using various evolutions of silicon anode up to 2030. The results showed that the current anode active material accounts for around 7% to 9% of total cell costs in NMC811 (80% nickel, 10% manganese, and 10% cobalt) and LFP chemistries, a figure which is expected to reduce to around 2% by 2030 with the adoption of optimized microsilicon at scale.

Silicon anodes are set to increase their market share. Analyst BloombergNEF says anode technology could lean on silicon, lithium, and hard carbon to displace 46% of graphite demand in 2035, compared to scenarios in which the market doesn’t shift away from graphite. While the analysts expect hard carbon used in sodium ion batteries to already start entering the market in 2024, lithium metal anodes are projected to start playing a more prominent role only beyond 2030.

Bigger, better

As the search for new battery materials continues, so does innovation on the cell level. In battery energy storage system (BESS) applications, however, cost remains the key driver for adjustments at cell level. The obvious way of bringing down bill-of-materials (BOM) costs is by increasing the capacity and size of cells. Another benefit is that fewer cells means less work for the battery energy management system. Finally, the number of connection points and the complexity of mechanical trays are also reduced, making manufacturing processes easier.

Several manufacturers have already transferred from 280 ampere-hour (Ah) to 300 Ah-plus cells, with larger capacities in the pipeline. With the former seen as a standard in utility scale storage projects in 2023, the 300 Ah-plus cells stand ready to power commercial projects in 2024. Christoph Neef, senior scientist and project manager at Germany’s Fraunhofer Institute for Systems and Innovation Research ISI, observed that the trend toward high-capacity cells does not come from the electric vehicle (EV) industry, where only cells up to 200 Ah are usually deployed.

“The reason is simple: the system sizes are rather small compared to industrial BESS’, e.g. only 70 kWh,” said Neef. “Nevertheless, a system voltage of more than 300 V or, in future, 800 V should be achieved. This is simply not possible with a few high-capacity cells connected in series. The effects of the failure of a single cell would also be incalculably high.”

In other words, 300 Ah-plus cells are a clear indication battery cell manufacturers are increasingly developing products tailored to the BESS market and slowly moving away from the dominance of EV-customized cells.

Most cell manufacturers offer 300 Ah-plus cells with the same dimensions as 280 Ah devices, which makes the job easier for system integrators when designing their products. Large cells pose a greater challenge for safety management, however – particularly in terms of ensuring temperature uniformity within cells.

“The larger the individual cell, the greater the impact if a cell fails,” said Neef. “However, we do not assume that this has any effect on the fire risk.” Large-format cells, with more than 300 Ah with LFP chemistry, are likely to exhibit similar behavior in the event of a short-circuit as smaller units. The impact on the long-term reliability of the system could be higher, however. Precise cell monitoring and predictive maintenance are becoming increasingly important as a result.

“What is very interesting, however, is that the production quality of cell manufacturers is now so high that large-format cells are also worthwhile from the point of view of rejects,” added Neef. “The larger the cell capacity, the higher the risk of defects, e.g. in the electrode, and therefore the higher the risk of producing poor-quality cells. Only with very low defect rates is the production of these large cells worthwhile. [It is] a sign of the maturity of the industry.”

System evolution

Such bigger cells have led to bigger capacities at the container level. Average capacities have moved from more than 3 MWh to more than 5 MWh for the same 20-foot-equivalent units. Such higher energy-density BESS’ come with a host of advantages. For instance, they make it possible to install bigger capacities on a smaller footprint and thus save on land use – a particularly important consideration in regions facing space constraints.

“Less number of cells per watt-hour also reduces assembly and packaging and saves cost during production processes,” said Anqi Shi, senior analyst for batteries and energy storage at S&P Global. “However, challenges occur in system design and safety measures as heat dissipation and consistent temperature is harder to achieve.”

Another pronounced development at the system level is the move from air cooling to liquid cooling. In 2023, many system integrators released new BESS products with liquid cooling, describing it as an upgrade in terms of efficiency and the lifespan of grid scale products. Compared to the previously ubiquitous air cooling method, liquid cooling is better geared to deal with temperature-related challenges and is able to reduce land footprint, with some manufacturers reporting saving more than 20% of floor area.

That technology uptake has been particularly pronounced in China, where the lion’s share of large scale energy storage project tenders require liquid cooling technology. Shi said liquid cooling is especially suitable for high energy-density BESS’, or for projects where fast charging and discharging, and wide ambient temperature changes, are expected. “However, while liquid cooling offers better heat dissipation efficiency and temperature uniformity inside the BESS, the cost is higher than air cooling and there could be a risk of coolant leakage,” added Shi.

Finally, a potential new trend could be the emergence of alternating-current, “AC blocks” – containers with both battery and power conversion systems (PCS’) integrated inside. That type of product was pioneered by Tesla, in the company’s 2022 Megapack redesign. “AC blocks offer easier and quicker installation on site, less land occupation, and decentralized (pack-level or rack-level) control of BESS’,” said Shi. “They come at a cost premium, mostly due to using string PCS’, but the cost could be reduced by scaling up production.”

Currently, only Sungrow and Tesla have AC blocks that are larger than 3 MWh in a single container. Other relatively newer players, including Rimac Energy and JD Energy, have less-than-1 MWh AC block containers which might not have the same land-use advantage. It is not yet clear whether AC blocks can become a mainstream trend. After all, not all system integrators have in-house PCS capability. As Shi noted, however, AC blocks give developers increased choice and further squeeze established players in an already fiercely competitive market.

From pv magazine Global

Researchers led by Dartmouth College in the United States have identified zintl-phosphide (BaCd2P2) as a potential new absorber material for thin-film solar cells after conducting a high-throughput (HT) computational screening among 40,000 promising inorganic materials.

“Based on its dopability, this material could be used as a p-type absorber layer for pn junction cells or as an intrinsic absorber layer for p-i-n cells,” the research’s corresponding author, Zhenkun Yuan, told pv magazine.

The group selected the inorganic materials from the Materials Project database, which is an open-access database describing material properties that can be used to accelerate the development of a given technology by predicting how new materials, both real and hypothetical, can be potentially utilized.

Through the screening, the scientists initially identified materials that offer a suitable band gap, small effective masses, and promising defect properties. “Among these promising candidates, we select the zintl-phosphide (BaCd₂P₂) and explicitly show that the computed nonradiative recombination rates in BaCd₂P₂ are better than or comparable with those in high-efficiency solar absorbers such as the halide perovskites,” they explained.

After identifying the material, the group found that zintl-phosphide can be very stable both in air and water. “You can put it out for six months and it will stay the same,” added co-author Geoffroy Hautier. “When you don’t have to worry about moisture and air contamination, that significantly reduces your costs.”

By conducting bright photoluminescence (PL) and time-resolved microwave conductivity (TRMC), it also found the material has a potential energy bandgap of 1.45 eV and a carrier lifetime of up to 30 ns.

“All of these results indicate that BaCd₂P₂ is a promising high-performance solar cell absorber with the potential to open a new avenue in PV for an entire family of Zintl AM₂X₂ solar absorbers, where A and M are +2 ions and X is a pnictogen,” the researchers said.

“We won’t have it as a solar panel tomorrow,” added Hautier, “but we think this family of materials is exceptional and worth looking at.”

Their findings were presented in the paper “Discovery of the Zintl-phosphide BaCd₂P₂ as a long carrier lifetime and stable solar absorber,” published in Joule.

New York State Governor Hochul announced $16 million is now available to advance hydrogen projects through the Hydrogen and Clean Fuel Program. The program funds research, development, and demonstration projects of clean hydrogen for industrial processes, transportation, energy storage, and grid support. 

The program is currently accepting funding applications for product development proposals and pilot demonstration projects. Applications will be accepted through July 15, 2024. 

Clean or “green” hydrogen differs from traditional “blue” hydrogen, by using renewable energy sources like solar and wind rather than fossil fuel-based electricity. The buildout of clean hydrogen is expected to address hard-to-decarbonize end uses. 

The funding round comes as part of the pursuit of New York’s Climate Leadership and Community Protection Act goal to transition to 100% zero-emission electricity by 2040, one of most ambitious state climate goals in the union. 

New York’s scoping plan calls for 18 GW of zero-carbon, firm, dispatchable long duration energy storage capacity is required by 2050. 

“New York is taking the lead to build a clean hydrogen ecosystem and growing the nascent industry,” said Governor Hochul. 

The program will be administered by New York State Energy Research and Development Authority (NYSERDA).  

“While tax credits included in the U.S. Inflation Reduction Act will significantly improve the economics of clean hydrogen projects, the reality is that individual states must also take direct action to accelerate domestic clean hydrogen production and use,” said Hydrogen and Low Carbon Fuels Regional Head DNV Amit Goyal.  

Funding for these initiatives is through the New York’s 10-year, $6 billion Clean Energy Fund (CEF) and the Regional Greenhouse Gas Initiative (RGGI). 

“NYSERDA’s initiative for industrial process heat applications, high volume dense storage, supporting microgrids and enabling heavy duty transport is exactly the kind of state-level support that is needed to complement federal incentives and help further catalyze the hydrogen economy,” said Goyal. 

Read more pv magazine USA coverage on hydrogen. 

247Solar closer to commercializing modular concentrating solar plant Taking a page from the solar PV and wind industries, the 247Solar Plant is modular and the majority of its components are mass produced and can be assembled at the site.

Direct pay process, tax credit transfer recapture risk and more At the Solar Energy Industry Association’s annual event in Times Square, experts delved into the complexities of the Inflation Reduction Act and its impact on solar financing.

Major U.S. bank signs $140 million tax equity deal for Louisiana solar project Barclays and Lightsource bp agree to finance deal to construct 180 MW Prairie Ronde solar farm in St. Landry Parish.

Florida-based rooftop solar and storage company goes public Regional solar, storage, and energy efficiency provider Sunergy: By Zeo Energy joined the NASDAQ exchange following an acquisition by ESGEN Acquistion Corp.

After-sale support key to boosting off-grid solar A new survey from US-based impact measurement company 60 Decibels shows off-grid energy customers are currently facing a series of challenges such as product affordability, gender inequality, customer support, further investment in minigrids, and over-indebtedness. The report, however, reveals that most users say the quality of their lives “very much improved” thanks to off-grid PV.

U.S. scientists build hybrid energy system integrating PV, radiative cooling The hybrid system has a cooling power of 63.8 W/m2 and a photovoltaic power output of 159.9 W/m2. According to its creators, the cooling capacity provided by the system can be used in buildings or refrigerators.

A “Swiss Army Knife” for home energy management FranklinWH chief commercial officer Vincent Ambrose met with pv magazine USA to share his view of the evolving home energy storage industry.

Under development for more than a decade, 247Solar announced it is one step closer to commercializing its solar thermal electric generating technology with an $8 million Series A funding round, $6 million of which has been closed to date.

The company produces “247Solar Plants” that are capable of producing 400 kW of electricity from 1,800 F heat using a solar receiver design. It is a proprietary thermal storage system with a unique turbine, to produce 24/7 solar electricity. 247Solar told pv magazine USA that each plant module simultaneously produces continuous 400 kW of electricity and 600 kWth of industrial heat at 482 F.

The system can generate heat and electricity 24 hours a day, seven days a week. Like traditional concentrating solar power (CSP), 247Solar’s technology uses mirrors to reflect sunlight onto a receiver tower. The tower is 120 feet tall, shorter than traditional CSP towers, and its turbines run on hot air at normal atmospheric pressure, which the company said reduces the system’s complexity.

The intellectual property for the turbine involves a high-temp heat exchanger that replaces the combustor in an otherwise standard Capstone C200 turbine, 247Solar told pv magazine USA. The heat exchanger is based on a design developed by the late MIT professor emeritus David Gordon Wilson. MIT owns the patent for the heat exchanger and 247Solar licenses it from them.

247Solar adapted the heat exchanger to the turbine and tested a prototype in collaboration with Brayton Energy, a New Hampshire based firm that is focused on development of advanced energy technologies.

Another novel aspect of the 247Solar Plant is the energy storage method. Rather than storing the heat in molten salt, the system stores it in inert materials such as sand, ceramics or iron slag for 18 hours or more. When the heat is released, it spins the turbines to generate electricity and industrial-grade heat when it’s needed.

The ability to scale to any capacity is key to this technology, and 247 said its units fit on 5 acres of land. Because the setup is modular, the parts can be built in factories and assembled at the site.

“We’ve been refining our technology for more than a decade and have emerged with groundbreaking products that can provide zero-carbon electricity and heat around the clock with a small footprint, low technology risk, low environmental impact, and a long operating life,” said Bruce Anderson, founder and CEO.

From pv magazine Global

AtmosZero said it has raised $21 million in a Series A funding round. The company said it will use the funds to accelerate the commercialization of its Boiler 2.0 technology.

“Boiler 2.0 can easily be combined with PV power generation and storage,” a company spokesperson told pv magazine. “The tech runs off electricity and it doesn’t matter how that electricity is created, just that it’s there.”

Most industrial steam is generated by burning fossil fuels on-site in boiler systems. It is used in a range of industries, from food and beverage to chemical manufacturing, accounting for about 8% of global energy use.

“AtmosZero’s proprietary Boiler 2.0 technology extracts heat from the air and delivers high-temperature steam with maximum efficiency and zero carbon emissions, allowing companies to replace their existing natural gas and oil boilers quickly and cost-effectively,” the spokesperson said.

The heat pump draws 480 V of voltage in a three-phase configuration and can produce 650 kW of thermal energy, with an output flow of 997.9 kg/hr of saturated steam. Its output temperature-pressure ranges between 120 C/199.8 kPa and 165 C/701.7 kPa.

“The coefficient of performance (COP) of the system is dependent on the ambient temperatures as well as the desired steam temperature,” the spokesperson said. “We work together with customers and perform specific analysis to give them a better insight on expected performance. That being said, our target is a COP of 2 going from 15 C ambient to 150 C saturated steam.”

The system uses an unspecified refrigerant with “low global warming potential (GWP), flammability, and toxicity.” Its footprint is approximately 2.4 meters x 6.1 meters.

AtmosZero is currently testing the system under a full-scale pilot deployed at a facility operated by US-based New Belgium Brewing Company. It also recently launched a European subsidiary.

“Our first systems deploying in 2025 will produce 165 C and in 2026 we will achieve 200 C,” the spokesperson said.

From pv magazine Global

Researchers at Penn State University in the United States have fabricated a prototype of a hybrid energy system integrating solar cells for power production and radiative cooling for external cooling purposes.

Radiative cooling occurs when the surface of an object absorbs less radiation from the atmosphere and emits more. As a result, the surface loses heat and a cooling effect can be achieved without the need for power.

“The photovoltaic electricity generated in the dual system can be used for energy storage or be converted to alternating current by using an inverter,” the scientists said. “The coldness achieved on the transparent radiative cooler can be used to cool air or liquid, which can be driven by fan or pump, respectively, to interface with thermal systems for energy savings.”

The proposed system achieves simultaneous subambient daytime radiative cooling and photovoltaic electricity generation from the same area. “At night and during the day, the radiative cooler works as a 24/7 natural air conditioner,” said the research’s lead author Pramit Ghosh. “Even on a hot day, the radiative cooler is cold to the touch.”

The system consists of a transparent low-iron glass radiative cooler that is able to transmit 91% of sunlight, a visibly transparent infrared-opaque layer, and a 125 mm × 125 mm interdigitated back-contact (IBC) photovoltaic cell provided by US-based manufacturer Maxeon. The radiative cooler has no direct radiative heat exchange with the PV device.

The scientists tested the system in an outdoor environment at Penn State Sustainability Institute’s Sustainability Experience Center and found it could surpass the electricity saving of a bare solar cell by as much as 30%. “We demonstrated simultaneous subambient daytime radiative cooling at 5.1 C temperature reduction under solar irradiance of about 1,000 W/m² and solar power generation up to 159.9 W/m² from the same area,” they explained. “We experimentally achieved ambient cooling power of 63.8 W/m² under peak sunlight and ambient cooling power of 87.0 W/m² at night.”

The research group also assumed the power generated by the solar cell to be utilized to power a cooling system with a coefficient of performance (COP) 2.8, and found the cooling power of the hybrid system would be five times more than the daytime cooling power achieved in conventional solar-reflective radiative coolers.

“Our work highlights the significant opportunity of simultaneously harvesting both the sun and the cold universe for renewable energy at a level that can exceed the performance of using either resource alone,” it concluded.

The system was described in the study “Simultaneous subambient daytime radiative cooling and photovoltaic power generation from the same area,” which was recently published in Cell Reports Physical Science.

Radiative cooling was recently applied to solar panel cooling by researchers from Saudi Arabia’s King Abdullah University of Science and Technology (KAUST), Shanghai Jiao Tong University in China, Purdue University in the United States, the Catalan Institute of Nanoscience and Nanotechnology and the Instituto de Ciencia de Materiales in Spain, and the Jordan University of Science and Technology and the Australian College of Kuwait, among others.

People on the move: 247Solar, iSun, Earthrise Energy and more Job moves in solar, storage, cleantech, utilities and energy transition finance.

Tandem solar cell based on cadmium telluride, iron disilicide promises 43.9% efficiency Researchers in Bangladesh have designed a dual-junction tandem solar cell with a bottom device based on iron disilicide (FeSi2), an emerging absorber material know for its high thermal stability and good optoelectronic properties. Their simulation showed the advantage of combining the larger bandgap of the top cadmium telluride cell and the smaller bandgap of the bottom FeSi2 cell.

DOE Loan Programs Office announces $72.8 million for microgrid on Tribal lands The 15 MW / 38 MWh Viejas Microgrid is the first project to be offered a conditional commitment through the Tribal Energy Financing Program.

New Mexico Supreme Court upholds Community Solar Act  A New Mexico judge upheld rules that prevent utilities from deducting transmission costs from solar bill credits received by customers.

Mitigate lithium-ion battery fire risk for manageable premiums As debate continues to rage about the best ways to deal with battery fires, a risk management professional and an insurance underwriter discuss some golden rules for project developers.

Solar asset underperformance estimated to cause $4.6 billion in preventable losses Analyzing a global dataset of 125 GW of PV systems, drone operator Raptor Maps marked a rising trend of system underperformance.

California rulemaking requires health and environment assessment in energy policy decisions The California Energy Center must now assess costs and benefits related to health and environmental externalities of energy generation and transmission.

From pv magazine global

Researchers at the University of Rajshahi in Bangladesh have simulated a dual-junction tandem solar cell based on two PV devices reyling on absorbers made of cadmium telluride (CdTe) and iron disilicide (FeSi2).

Inorganic FeSi2-based solar cells have recently drawn a lot of attention from the scientific community as these devices offer superior thermal stability and good optoelectronic properties compared to conventional solar cells. Furthermore, Fe and Si used to form FeSi₂ are abundant in nature.

The scientists explained that their tandem cell takes advantage of combining the larger bandgap of the top CdTe cell and the smaller bandgap of the bottom FeSi2 cell. “The top cell transforms photons with elevated energy efficiently while minimizing thermalization losses and transmitting the solar spectrum in the close-infrared region light to the lower cell,” they highlighted. “In order to improve light absorption, it is crucial to reduce the undesired losses at the junction resulting from Fresnel surface reflection.”

The scientists used the SCAPS-1D solar cell capacitance software, developed by the University of Ghent, to simulate the novel cell configuration. They assumed the top cell to be built with an n-type cadmium sulfide (CdS) window layer, the CdTe absorber, and a back surface field (BSF) based on molybdenum disulfide (MoS₂). The bottom cell was designed with an n-type CdS window layer, the FeSi2 absorber, and a copper tin sulfide (Cu2SnS3) BSF.

In the simulation, the team considered parameters such as energy bandgap, diffusion length, and doping concentration. “CdTe has featured a 1.5 eV bandgap and a 4.28 eV electron affinity, while the bandgap and electron affinity of FeSi₂ are 0.87 eV and 4.16 eV, respectively,” it specified. “An optimal, slender tunnel junction connecting the upper and lower cells with monolithic architecture has been assumed for the electrical linkage.”

The numerical analysis showed that the top CdTe cell may potentially achieve a power conversion efficiency of 26.13%, while the FeSi₂ bottom cell may reach up to 35.25%. It also demonstrated that the tandem device may achieve an efficiency of 43.91%, an open-circuit voltage of 1.928 V, a short-circuit current of 25.338 mA/cm², and a fill factor of 88.88%.

“These results suggest the practical feasibility of fabricating high-performance CdTe–FeSi₂ double-junction tandem solar cells for efficient solar energy conversion,” the scientists affirmed.

The cell was described in the study “Design and optimization of a high efficiency CdTe–FeSi₂ based double-junction two-terminal tandem solar cell,” published in Heliyon.

From pv magazine Global

Canadian solar simulator developer G2V Optics and Sinton Instruments, a US-based PV characterization specialist, have created a solar simulator for solar cells and modules.

The new instrument supports both characterization and a Class AAA light in a single tool. It is designed to test all solar cell technologies, but with a focus on perovskite-silicon tandem cells and encapsulated mini-modules. It contains a fully programmable and tunable spectrum steady-state LED light combined with Sinton Instruments’ solar cell testing hardware and advanced characterization analysis software.

Named FCT-650SE, the instrument has a multi-source LED solar simulator with up to 36 tunable channels for spectrum control, integrated current versus voltage (IV) curve recording, and Suns-Voc measurement capability. It can perform both flash and continuous lighting tests. Also supported are maximum power point tracking (MPPT), light soaking, and automated measurement sequences.

Some of the supported tests and measurements include full IV curve, short circuit current, open circuit voltages, maximum power point, fill factor, efficiency, series resistance, shunt resistance, and Suns-Voc. For silicon devices, it can also measure bulk lifetime, lifetime at max power, substrate doping, substrate thickness, and power loss analysis.

The system has a footprint of approximately 4,645 cm2, which the manufacturer said is on par or slightly more compact than other solar simulators with similar illumination areas.

Its voltage and current range are 40 V and 20 A for silicon and 2.4 A for perovskite tandem devices. The temperature-controlled chuck can accommodate samples that range in size from 2 mm2 to 210 mm2. Custom chuck designs for unusual sizes are available from the manufacturer.

The testing instrument is available from both companies. Several units have already been built and delivered to customers, according to the manufacturers.