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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

From pv magazine Global

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

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

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

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

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

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

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

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

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

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

From pv magazine Global

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

From pv magazine

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

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

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

Lab to fab

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

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

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

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

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

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

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

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

PV modules

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

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

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

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

Achieving stability

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

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

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

By Jan Oliver Löfken.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

From pv magazine Global

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

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

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

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

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

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

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

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

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

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

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

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

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

From pv magazine global

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Community solar

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

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

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

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

Total installed community solar capacity at the end of 2023:

1. New York 1.72 GW
2. Minnesota 904 MW
3. Massachusetts 852 MW
4. Illinois 251 MW
5. Maryland 149 MW
6. Colorado 147 MW
7. New Jersey 137 MW
8. Oregon 29 MW
9. Hawaii 4 MW

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

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

From pv magazine Global

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

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

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

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

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

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

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

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

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

From cells to module

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The U.S. Department of Energy’s Solar Energy Technologies Office (SETO) recently announced the 2024 Photovoltaics Research and Development program. This new initiative aims to distribute $20 million across eight to fifteen teams, with individual grants ranging from $1 to $4 million.

SETO has outlined two main focus areas for this funding: “Photovoltaic Advances in Cell Efficiency, Reliability, and Supply Chain,” and “Building Academic Capabilities in Cadmium Telluride”.

The first area seeks to develop solar cell and “minimodule” prototypes aimed at lowering module costs and the carbon footprint of manufacturing and supply chains. This includes advancements in building-integrated and vehicle-integrated solar systems. SETO is particularly interested in projects that promise low-carbon synthesis of metallurgical-grade silicon and innovative designs for crystalline, III-V, and organic solar photovoltaic cells.

The initiative also aims to address the high costs of III-V solar cells, currently priced at $77/Wdc, making them non-competitive for terrestrial solar generation. For metallurgical-grade silicon, the goal is to reduce CO2 emissions from the current 4 to 5 kg CO2 per kg of 2N c-Si (solar-grade silicon) to less than 1 kg CO2 per kg of silicon. It is expected that between six and ten awards will be distributed, ranging from $1 to $1.5 million each, totaling $10 million.

The second focus area targets advancements in cadmium telluride technology, which could greatly benefit First Solar, America’s leading solar panel manufacturer. This funding will support projects that require the development or upgrade of cadmium telluride research facilities. The objective is to enhance the design and testing processes within the cadmium telluride research community, facilitating rapid advancements and technology transfer.

Additional priorities under this funding include:

• Increasing the rate of learning and speed of advancement in CdTe cell and module research. 
• Improving the efficiency, durability, and energy yield of state-of-the-art CdTe PV cells. 
• Developing and validating new CdTe PV cell designs that have the potential to substantially outperform the current state of the art.  
• Improving the quality and scale of materials produced at academic institutions to facilitate technology transfer to industry.

For this second topic, SETO expects to allocate two to five awards, each ranging from $1 to $ 4 million, with a total allocation of $10 million.

Key dates for the program are:

Independent clean energy think tank Ember released a report recapping the growth of renewable energy worldwide, reporting that renewable energy generated about 30% of electricity across the globe in 2023.

Solar generation growth increased 23% globally, wind grew 10%, while fossil fuel generation grew only 0.8% last year, said the report. Renewables have expanded from 19% of global electricity in 2000, driven by an increase in solar and wind from 0.2% in 2000 to a record 13.4% in 2023.

“Solar is leading the energy revolution,” said the report. “It was the fastest-growing source of electricity generation for the 19th year in a row, and surpassed wind to become the largest source of new electricity for the second year running.”

China was the main contributor to solar growth in 2023, accounting for 51%. Other major contributors were the EU (12%) and the U.S. (11%). Together the four solar growth economies, China, EU, the U.S., and Brazil, accounted for 81% solar growth in 2023.

Solar reached a 5.5% share of the global electricity mix, reaching 1,631 TWh, rising from 4.6% in 2022.

“Despite reaching new record highs, the absolute growth in wind and solar (+513 TWh) was below expectations and slightly smaller than in 2022 (+517 TWh). This was mainly due to lower-than-expected wind growth, which was 18% lower compared to the 249 TWh increase in 2022,” said Ember.

Demand for electricity grew by 637 TWh globally in 2023, rising 2.2%, or the equivalent of adding the entire electricity demand of Canada to the total. This brought global electricity demand to a record 29,471 TWh. The increase in demand in 2023 was slightly lower than the average annual increase over the previous decade of 2.5%.

Solar and wind met most of the increased electricity demand globally, adding 513 TWh of generation, or about 82% of new demand.

“Despite their lower-than-expected growth, solar and wind were the powerhouses of newly added clean electricity,” said the report. “In aggregate, all other clean electricity sources fell – small rises in bioenergy and nuclear were not enough to counter the large fall in hydro generation caused by extensive droughts. Together, all clean sources met 79% of the increase in electricity demand, creating a shortfall that was met by fossil generation.”

The unprecedented growth of solar energy is leading the charge toward a carbon-free energy system, said Ember. In the decade of 2000 to 2010 cumulative global capacity doubled every two years, then from 2010 to 2023 the rate slowed to doubling every three years. The International Energy Agency (IEA) said that if solar deployment continues along an arc of doubling every 3.8 years from 2023 to 2030, the world will be on-pace for its Net Zero Economy scenario.

“Solar capacity has boomed due to steep declines in costs, supportive policy environments, technology efficiency improvements, and increased manufacturing capability,” said Ember. “A key to the rapid rise is Wright’s law of technology learning curves, whereby the technology gets cheaper as it is deployed more and it is deployed more as it gets cheaper.”

Combined with nuclear, the world generated about 40% of its electricity from low-carbon sources in 2023. Ember said this has resulted in CO2 intensity of global power generation falling 12% lower than its peak in 2007.

However, despite the average emissions per unit of energy generated decreasing in 2023, carbon emissions are higher than ever. Absolute fossil fuel generation increased 0.8% over the year, and global emissions increased by 1%, reaching 14,153 million tons of CO2 emitted by electricity generation.

“2023 came very close to becoming the first year of a new era of falling power sector emissions,” said Ember. “As clean electricity growth continues, we have growing confidence that in 2024, it will rise above electricity demand and lead to a fall in emissions.”

Clean energy capacity growth was already large enough to deliver a decline in emissions 2023, but a record fall in hydropower generation due to droughts prevented that. Ember said that 2023 likely marked the peak of power sector emissions.

“A signal is emerging from the noise of year-on-year variability: the world is at the peak, and about to enter a new era of falling power sector emissions,” said Ember.

From pv magazine Global

A group of researchers from the University of Cantabria in Spain has conducted a pilot project for a self-sufficient home that runs exclusively on photovoltaics, batteries, and hydrogen storage.

“This plant combines PV panels and hydrogen (PVHyP) as a method of seasonal energy storage, achieving the ambitious target of accomplishing an electrically self-sufficient social housing unit throughout the year,” the group said. “To achieve this goal, a tailor-made energy management strategy (EMS) has been developed based on the state of charge of the battery pack and the energy flow within the PVHyP, ensuring that the electrical consumption of the home is always covered either through PV panels, fuel cell or battery pack.”

For their simulation, the scientists collected data from January 2022 to December 2023 for an 80 m2 social home that is located in Novales, a small village in northern Spain. Electricity bills from the years before the renewable electrification of the house showed that it consumed 2,513 kWh/year with an average daily consumption of 6.88 kWh. The average consumption in the winter and fall was over 7.3 kWh, and in summer, 5.88 kWh/day.

With these data, the scientists moved to size the energy system using software optimization and market analysis. Finally, they settled on 20 solar panels with a power of 40 W each placed on the roof, as well as four 2.4 kWh batteries. The rest of the plant was installed in a shed in the neighboring plot. That included a 35 L water tank that used tap water after purification for electrolysis and a 600 L hydrogen storage tank at 300 bar.

With the proposed system configuration, the PV panels first must supply the house load. The excess generation will then charge the battery, and once that is full, it is stored in a high-pressure storage tank in the form of hydrogen generated by an electrolyzer.

“When the solar irradiation is insufficient to cover the demand of the house, the batteries supply the necessary energy to the dwelling,” explained the academics. “If the batteries are discharged, the fuel cell generates electricity to charge the batteries from the stored hydrogen. As far as possible, the hydrogen stored in the buffer is used first to avoid the compression stage, thus increasing energy efficiency. The system and the house are connected to the grid on a self-consumption basis to sell back to the grid all the excess energy.”

According to the research group, the house demonstrated self-sufficiency, and its LCOE decreased from €0.86($0.92)/kWh to €0.34 /kWh, and the tenants saved €1,170 annually. “Almost 15,200 kWh have been saved from fossil fuels, which corresponds to approximately 2,260 kg of CO2,” emphasized the researchers.

They presented their findings in the study “Sustainable and self-sufficient social home through a combined PV‑hydrogen pilot,” published in Applied Energy.

Global actions, or inactions, are likely to lead to a rise in the average planetary temperature by more than 1.5°C due to escalating carbon dioxide levels. This potential rise has led researchers to examine the consequences using the Representative Concentration Pathway 4.5 Scenario, which predicts a 4.5°C rise. Many scientists warn that such warming could present significant global challenges.

In response to these findings, a team from the University of Michigan projects that climate change induced warming could increase the value of residential rooftop solar by between 19% and 25%. This expected rise in value is primarily attributed to increased demand for on-site electricity, complemented by a slight boost from enhanced solar electricity generation due to fewer cloudy days anticipated in the future.

The logic behind the first factor is simple: higher temperatures will necessitate increased use of air conditioning, leading to greater electricity consumption. As a result, buildings can derive more value from the solar power generated on their roofs by utilizing it immediately. This direct usage reduces reliance on net metering and diminishes dependency on distribution and transmission lines.

The study estimates that climate change could increase total household cooling energy by 40% to 100% in cities across various U.S. cities. The impact, however, varies by location; Miami experienced the most significant increase, while Minneapolis, situated much farther north, saw a slight decrease in the financial benefits of rooftop solar for households, specifically in terms of cooling costs. Among the 17 cities analyzed, Minneapolis was the only one to report a reduction in electricity consumption, due to its increasingly temperate weather.

Numerically, the analysis indicates that the electricity required for cooling these locations, measured in kilowatt-hours per year per square meter, will increase from 5, 11 and 24 kWh/m2 in cold, mild, and hot cities to 9, 16 and 31 kWh/m2, respectively, by the end of the century.

A second layer of analysis examined the potential electricity generation by solar panels under future weather conditions, revealing mixed results. Rising temperatures are expected to reduce solar power efficiency, thus decreasing their output. Conversely, the models suggest fewer clouds on average, which would boost generation.

Weather effects, which vary regionally, significantly impact solar output. For example, persistent high pressure in the upper atmosphere could drive solar irradiance up to 30% above normal, setting new records for solar generation and temperature in North America as seen in mid-February 2024.

The research team indicated that these two variables, when considered across all 17 cities, essentially neutralize each other.

Additional considerations for the value of residential rooftop solar in times of climate complexity include enhancing local resiliency and reducing the need for costly upgrades to distribution and transmission power grid infrastructure.

The U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has updated its Best Research-Cell Efficiency Chart with the inclusion of a new cell category – Hybrid Tandems.

“This category collects record tandem cells with layers composed of two different PV materials. Some subcategories of Hybrid Tandems (Perovskite/Si and Perovskite/CIGS) were already present in the previous format under ‘Emerging PV,’ whereas others (III-V/Si and Perovskite/organic) are new,” the research institute said in a statement. “All of these subcategories have been moved into the new Hybrid Tandems category—with the exception of perovskite/perovskite tandems, which are listed under Emerging PV.”

The NREL stressed that all these changes are now reflected in the interactive 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 research institute recently told pv magazine, noting the chart also includes important results achieved in the first quarter of this year.

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 U.S.-based thin-film module maker First Solar for a solar cell based on copper, indium, gallium and diselenide (CIGS) technology.

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

According to the U.S. Department of Energy, 70% of transmission lines are over 25 years old and approaching the end of their typical lifecycle. Grid upgrades that deploy modern grid technologies are sorely needed, and federal funding is available through the Grid Resilience and Innovation Partnership (GRIP) program, which recently closed applications for up to $2.7 billion in DOE grant funding under a second round.

Grid modernization has been underway in some states more than others, and the North Carolina Clean Energy Technology Center recently released The 50 States of Grid Modernization: Q1 2024 Quarterly Report, which looks at legislative and regulatory action related to smart grid and advanced metering infrastructure, utility business model reform, regulatory reform, utility rate reform, energy storage, microgrids, and demand response.

In Q1 2024, according to the report, 49 states plus DC and Puerto Rico took a total of 567 policy and deployment actions, the most common related to policies (133), financial incentives (108), and utility business model and rate reform (93).

Five top policy developments

Maryland: Lawmakers passed the Distributed Renewable Integration and Vehicle Electrification (DRIVE) Act in Maryland that directs the Public Service Commission to develop a program for utilities to establish virtual power plant (VPP) pilots to compensate owners and aggregators of distributed energy resources for distribution system support services.

Massachusetts: Eversource, National Grid and Unitil filed final electric sector modernization plans in January 2024. The plans include a variety of programs and investments, such as VPP programs, advanced distribution management system and distributed energy resource management system investments, resilience upgrades, heat pump integration, and non-wires alternative

Connecticut: The Connecticut Public Utilities Regulatory Authority (PURA) issued a set guidelines for utilities’ advanced metering infrastructure plans, including a directive to include advanced time-of-use rates and to use Green Button Connect functionality. Later in the quarter, PURA filed a straw proposal on performance incentive mechanisms (PIMs), which includes four PIMs based on non-wires solutions, equitable reliability, distributed energy resource interconnection, and avoided service terminations.

Colorado: The Colorado Public Utilities Commission (PUC) approved guidelines and directives for VPP implementation in Xcel Energy’s service territory.

Maine: The Governor’s Energy Office in Maine released its final long-duration energy storage (LDES) study that identifies policy considerations and actions for the state to support LDES. The PUC also released a study that examines utility control or ownership of energy storage, finding that utility ownership of storage should only be allowed under certain circumstances.

Top trends

Grid-enhancing technologies can boost the use of any existing transmission system, according to a study by The Brattle Group, which looked specifically at advanced power flow control, topology optimization and dynamic line ratings. The NC State report said use of grid-enhancing technologies (GETs) is a notable trend and noted the following actions:

• Virginia lawmakers enacted a bill requiring utility integrated resource plans to include a comprehensive assessment of the application of GETs and advanced conductors. In
• Maine legislators enacted a bill requiring the PUC to conduct a review of available GETs that large investor-owned utilities may use to reduce investment needs in grid infrastructure.
• Minnesota lawmakers introduced bills requiring utilities to file plans regarding the implementation of GETs to prevent grid congestion at the transmission level.
• New York legislators introduced bills that would allow the Department of Public Service to approve requests from distribution companies to develop GETs.

Other states considering legislation initiating studies on GETs include Connecticut and New Hampshire.

Virtual power plants

VPPs give grid operators a utility-grade alternative to new generation and system buildout by automating efficiency, capacity support and offering non-wire alternatives, according to Jigar Shah, director of the U.S. Department of Energy Loan Programs Office. “By deploying grid assets more efficiently, an aggregation of distributed resources lowers the cost of power for everybody, especially VPP participants,” Shah said in an article in pv magazine USA.

According to the NC State report, a state policymakers and regulators are taking steps to develop frameworks for VPPs in their states:

• Pennsylvania regulators issued an advanced notice of proposed rulemaking seeking input on VPPs as a potential resource for the state.
• Maryland lawmakers passed a bill directing the Public Service Commission to develop a program for utilities to establish VPP pilots, with each investor-owned utility required to propose a pilot or temporary tariff by July 1, 2025.
• Colorado PUC issued a decision outlining rules for VPP pilots and acquisition.
• California and Hawaii regulators are also advancing expansive programs to promote VPPs.

Microgrids

Microgrids are groups of distributed energy resources, such as solar modules on a home, connected to a battery system, that can disconnect from the grid and operate independently during a power outage. The U.S. Department of Energy has a vision that 30% to 50% of electricity generation will come from distributed resources by 2035, with microgrids playing a key role in the transition.

The NC State report found that a growing number of states are evaluating the potential for microgrids to provide resilience or other benefits in their states.

• Colorado Energy Office is currently developing a microgrid roadmap, which will examine how microgrids can improve grid resilience and reliability in the state.
• New Hampshire lawmakers recently passed a bill requiring the state’s Department of Energy to study the potential benefits, risks and other factors of developing a microgrid framework.
• Rhode Island PUC issued request for proposal for a study related to microgrid program design.
• Puerto Rico Energy is examining revisions to its existing microgrid revisions.
• Arizona regulators issued a decision prohibiting Arizona Public Service from providing microgrid services.

Lawmakers in California, Iowa, New Jersey, and New York also considered legislation related to microgrid studies during the quarter.

Researchers from the University of Michigan have found that climate change will increase the future value of residential rooftop solar panels across the United States by up to 20% by the end of the century.

In “Climate change will impact the value and optimal adoption of residential rooftop solar,” which was recently published in Nature Climate Change, the researchers quantified the effects of climate change on rooftop solar value and optimal capacity. They analyzed data from 2,000 households across 17 US cities, estimating air-conditioning demand and solar panel performance under future climates.

Mai Shi, the study’s lead author, told pv magazine that this is the first study to quantify how climate change will affect the value of rooftop PV for households in the future.

“Value here means economic value – how much does a household save on its electricity bill when it installs rooftop solar,” Shi explained. “Our analysis captures how climate change will affect household electricity demand through increased cooling demand and household rooftop PV generation.”

The researchers said that rooftop solar value will increase by between 5% and 15% across a wide range of US cities under moderate climate change by the mid-century, and then by up to 20% by the end of the century.  Greater increased value was analyzed in homes with larger cooling intensities and cities with increasing radiation and higher power retail prices.

Across the 17 cities, Miami and Orlando are expected to see the strongest increase in solar value. Shi said that in these cities, climate change is expected to increase solar radiation, which in turn will favor more rooftop PV generation, while increases in air temperatures will lead to more household electricity demand.

“Given the average 25-year lifespan of a rooftop solar installation, a system built today will nearly experience 2050 weather. Therefore, it’s important for households to think of future value when building solar,” Shi said. “If households do so, our findings indicate they would see even greater value from solar, and might decide to build more.”

From pv magazine Global

A group of researchers from the University of Cantabria in Spain has conducted a pilot project for a self-sufficient home that runs exclusively on photovoltaics, batteries, and hydrogen storage.

“This plant combines PV panels and hydrogen (PVHyP) as a method of seasonal energy storage, achieving the ambitious target of accomplishing an electrically self-sufficient social housing unit throughout the year,” the group said. “To achieve this goal, a tailor-made energy management strategy (EMS) has been developed based on the state of charge of the battery pack and the energy flow within the PVHyP, ensuring that the electrical consumption of the home is always covered either through PV panels, fuel cell or battery pack.”

For their simulation, the scientists collected data from January 2022 to December 2023 for an 80 m2 social home that is located in Novales, a small village in northern Spain. Electricity bills from the years before the renewable electrification of the house showed that it consumed 2,513 kWh/year with an average daily consumption of 6.88 kWh. The average consumption in the winter and fall was over 7.3 kWh, and in summer, 5.88 kWh/day.

With these data, the scientists moved to size the energy system using software optimization and market analysis. Finally, they settled on 20 solar panels with a power of 40 W each placed on the roof, as well as four 2.4 kWh batteries. The rest of the plant was installed in a shed in the neighboring plot. That included a 35 L water tank that used tap water after purification for electrolysis and a 600 L hydrogen storage tank at 300 bar.

With the proposed system configuration, the PV panels first must supply the house load. The excess generation will then charge the battery, and once that is full, it is stored in a high-pressure storage tank in the form of hydrogen generated by an electrolyzer.

“When the solar irradiation is insufficient to cover the demand of the house, the batteries supply the necessary energy to the dwelling,” explained the academics. “If the batteries are discharged, the fuel cell generates electricity to charge the batteries from the stored hydrogen. As far as possible, the hydrogen stored in the buffer is used first to avoid the compression stage, thus increasing energy efficiency. The system and the house are connected to the grid on a self-consumption basis to sell back to the grid all the excess energy.”

According to the research group, the house demonstrated self-sufficiency, and its LCOE was cut by about one-third and the tenants saved $1,251 annually. “Almost 15,200 kWh have been saved from fossil fuels, which corresponds to approximately 2,260 kg of CO2,” emphasized the researchers.

They presented their findings in the study “Sustainable and self-sufficient social home through a combined PV‑hydrogen pilot,” published in Applied Energy.

Over 10 million homes are located within one mile of the 8,000+ large-scale solar (LSS) projects, as reported by Energy Markets & Policy (EMP) at the Lawrence Berkeley National Laboratory. This number is expected to grow significantly, despite efforts by certain groups to spread falsehoods and hinder progress. Solar power does remain the most popular form of electricity nationwide, despite its popularity declining in more conservative and rural areas as a result of targeted attacks.

To better understand the perceptions of those living near solar power facilities, the EMP team, in collaboration with the University of Michigan, conducted a comprehensive, 12-page survey that explored 49 different aspects of living near LSS projects.

Data solicited from 4,974 households was published in ‘Perception of Large-Scale Solar Project Neighbors: Results from a National Survey’. The group shared the responses from 984 households located within three miles of 380 unique LSS projects, with 71% of these households located within one mile of the projects.

According to the EMP study, neighbor attitudes remained fairly consistent until projects surpassed 100 megawatts, at which point the sentiment shifted dramatically, displaying a 12 to 1 ratio of negative to positive responses. This strong opposition was closely linked to concerns about the impact on local aesthetics, overall quality of life, and perceptions of unfairness in the project planning process.

Notably, only 20% of those surveyed were aware of the projects before construction began, and about one-third discovered the projects’ existence only upon receiving the survey. Those who see large solar installations on a daily basis were significantly more likely to express negative attitudes toward these projects.

When asked about expanding LSS projects and other types of energy infrastructure, respondents showed the strongest support for rooftop solar, with less than 10% opposition. Support for new LSS projects ranked second, followed by wind energy, gas plants, pipelines, wells, and nuclear energy, in that order.

Interestingly, if a solar power project must be built, agrivoltaic projects (which integrate agriculture with photovoltaic systems to maximize land use) received the highest approval ratings, with less than 10% expressing a negative view, and 50% being positive or very positive.

The results showed that 85% of these neighbors held a positive or neutral view of their local solar power projects, 11% viewed them negatively, and 4% had a very negative perception. Attitudes were slightly less favorable among those living within a quarter mile of a facility.

Overall, support for constructing additional solar facilities was strong, with 42% in favor and only 18% opposed. However, attitudes shifted significantly as project sizes increased. Research from upstate New York echoed these findings, showing a change in perception when projects exceeded 50 acres.

The NC Clean Energy Technology Center (NCCETC) released its Q1 2024 edition of its 50 States of Solar report, which looks at changes in policies on net metering, distributed solar valuation, community solar, residential fixed charges and more.

NCCETC is a public service center administered by the College of Engineering at North Carolina State University, with a mission to advance a sustainable energy economy by educating, demonstrating and providing support for clean energy technologies, practices, and policies. The Center is known for its DSIRE database that tracks incentives in all 50 states for renewable energy and energy efficiencies.

The Q1 2024 report finds that 43 states plus Washington DC and Puerto Rico took a total of 163 actions related to distributed solar policy and rate design. The map above summarizes state actions related to compensation for distributed generation (DG), rate design, and solar ownership. Of the 163 actions cataloged, the report authors note that the most common were related to DG compensation rules (56), followed by residential fixed charge and minimum bill increases (42), and community solar (37).

Trends spotted in the report include legislation to enable community solar, net metering reform considered by new states and states clarifying time of use rates for net metering customers.

Community solar is a way for homeowners, businesses and other organizations to invest in the benefits of clean energy when they have unsuitable conditions for rooftop or on-site ground-mounted installations. While installations of community solar contracted in 2022, Wood Mackenzie forecasts the U.S. community solar market to grow 118% over the next five years, with at least 6 GW expected to come online in existing markets between 2023 to 2027.

The NCCETC report finds that an increasing number of states are considering community solar legislation. For example, Pennsylvania recently passed a bill that would establish a community solar program, and similar bills are pending in Michigan, Ohio, and Wisconsin. Legislators in Missouri are taking a slightly different approach with bills introduced that direct electric suppliers to create three-year community solar pilot programs, and similarly, West Virginia lawmakers intend to create a pilot program. Alaska, Georgia and Iowa also have community solar bills pending.

It comes as no surprise that more states are considering changes to their net metering rules, following in the footsteps of California’s NEM 3.0, which has become the solar policy story of the year. In Delaware, for example, lawmakers  approved legislation to conduct a net metering cost-benefit study, and regulators in Wisconsin are also conducting a value of solar study. In Kentucky, Duke Energy wants to implement a net metering successor tariff that would involve real-time netting and reduced compensation for exported energy for new customer-generators. A Washington utility is preemptively amending net metering tariff language to close the tariff upon reaching an aggregate cap.

States and utilities are increasingly moving to time-of-use rates because they vary the cost of electricity according to when it’s used. For example, a solar-powered home generates electricity during the day, when rates are cheaper, but the household may use the most electricity in the evening, when it is more expensive. Examples of states taking steps to clarify how net metering is conducted on a time-of-use rate basis include Kansas, Maryland and North Carolina.

Maryland’s Public Service Commission recently directed its rate design working group to examine utility tariffs and propose any needed charges for net-metered customers under time-of-use rates. In South Carolina pending legislation would increase the state’s net metering system size limit, but only for customer-generators on time-of-use rates.

The Q1 report noted top solar policy developments, which are both good and bad for electric customers generating their own solar electricity. In Massachusetts, which has especially solar-friendly policies, regulators voted to allow electric customers to transfer credits across utilities. Plus some systems are exempt from the state’s net metering caps.

Virginia, historically a coal state, voted in 2020 to close all the state’s coal power plants by 2024. This is part of the forward-looking Virginia Clean Economy Act, which requires the state’s utilities to switch to 100% clean energy by 2050, while also adding 16 GW of solar and onshore wind, 3 GW of energy storage. Now legislators have gone a few steps further by passing bills that increase the capacity of Dominion Energy’s community solar program and direct regulators to set up a community solar program for Appalachian Power customers. Other bills under consideration in Virginia would expand solar leasing and power purchase agreements.

West Virginia, another former coal state, adopted net metering reforms that sets export credit rates at 8.91 to 9.343 cents per kWh in Monongahela Power & Potomac Edison’s rate case.

The Arizona Corporation Commission (ACC) approved a request from major utility Arizona Public Service to raise electricity rates for all customers, assess fixed charges, and to single out those who have invested in rooftop solar with the largest of such charges. The approved charge equals $0.242 per kW of on-site generation for customers on standard time-of-use rates and $0.215 per kW for customers on the time-of-use rate including a demand charge. The report notes that several participants have filed petitions for rehearing to overturn the grid access charge.

To produce the quarterly 50 states report, NCCETC reports that it looks at important proposed and adopted policy changes affecting solar customer-generators of investor-owned utilities and large publicly owned or nonprofit utilities serving at least 100,000 customers.

From pv magazine global

Researchers developed a novel vapor deposition method for all-inorganic perovskite absorbers using continuous flash sublimation (CFS).

They described the new technique as 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.”

The researchers said that they are pursuing vapor processing because of its potential for high yield, high-quality and high reproducibility processing, and its potential to eliminate the use of hazardous solvents. Furthermore, it is seen as simplifying the scaling up to larger device areas. In addition, its performance on rough surfaces makes it attractive for perovskite-based tandem applications.

“The limited throughput of vapor processes for the deposition of perovskite materials remains the number one bottleneck for a swift commercialization. Researching alternative deposition strategies is therefore key,” David Moore, a researcher from the US Department of Energy’s National Renewable Energy Laboratory (NREL) and co-corresponding author told pv magazine.

The scientists fabricated a variety of “high-quality” cesium lead halide (CsPb(I_xBr_1−x)₃) thin films in a prototype system to test the versatility of the CFS approach, noting that the process was able to produce thin film compositions “across the entire bromine/iodine space maintaining the composition of the source materials”.

They noted that the CFS approach enabled the reduction of the time required to deposit a “fully absorbing layer to less than 5 minutes” in a continuous deposition process.

The CFS-derived films were made into working solar cell devices. The study’s champion solar cells achieved power conversion efficiencies as high as 14.9%, open-circuit voltage of 1.17 V, fill factor of 76.0%, and short-circuit current densities of 16.8 mA cm−2. The forward scan direction values were 10.3%, 1.12 V, 55.1%, and 16.7 mA cm−2, respectively.

The researchers describe the source material, a mechano-chemically synthesized powder, and how it is prepared by mixing individual precursor materials, cesium and lead salts into a stochiometric powder. They said it was flashed at high temperatures to overcome the differences in deposition characteristics of the individual precursor materials.

The powder was filled into a reservoir connected to a vibratory feeder, which in turn was connected to an AC signal. After moving along the vibratory feeder, the powder falls into a preheated tantalum evaporation boat kept at a temperature “significantly above” the highest sublimation temperature of the individual inorganic salts, typically in the range of 700 C. “Inside the evaporation boat, the powder constituents instantaneously sublime, leave the evaporation source, to finally condense on a substrate situated above the evaporation boat,” explained the team.

An annealing step at temperatures between 330 C and 380 C for 0.5 min to 1 min was implemented after the CFS step to “improve thin-film quality and to ensure stabilization of the correct photoactive perovskite phase”. The details are described in “Continuous flash sublimation of inorganic halide perovskites: overcoming rate and continuity limitations of vapor deposition,” published in the Journal of Materials Chemistry A.

The team concluded that the work is a critical step toward fast and continuous processing of perovskite materials, which is “highly suitable for the fast deposition of thin films whose individual constituents have significant differences in sublimation characteristics.”

“I can imagine that a process like this could be used for the industrial fabrication of perovskites. Throughput is one of the number one bottlenecks of vapor processing of perovskites, so developing novel approaches that overcome this limitation are crucial,” Abzieher said, when asked about technology transfer potential.

Looking ahead at research activity, David Moore said that NREL, for example, is looking into the use of the CFS method for other hard-to-deposit material classes, as well as investigating using this method with other types of perovskite materials, such as hybrid materials containing organic and inorganic precursor materials.

Renewables and storage interconnection backlog grew about 30% last year  The wait for transmission interconnection studies constitutes a “major bottleneck” for solar, storage and wind projects, which accounted for over 95% of all active capacity awaiting studies at the end of 2023, Lawrence Berkeley National Laboratory has reported.

S-5! unveils new mounting systems for rooftop solar  S-5!, a supplier of mounting systems, plans to release two new mounting components for rooftop PV systems, including a new mount that allows for module-level power electronics to be attached directly to solar panel frames.

A guide to help homeowners understand how to go solar Researchers at Pacific Northwest National Laboratory published an open access guide to rooftop solar and battery energy storage that covers costs, incentives, policies and more.

New quantum solar cell material promises external quantum efficiency of 190% The new material consists of an heterostructure combining germanium, selenium, and tin sulfide, which also integrates atoms of zerovalent copper. It features an average photovoltaic absorption over 80% and could help photovoltaic cells break the Shockley-Queisser efficiency limit, according to its creators.

California’s electricity multi-crisis can be aided by virtual power plants By operating distributed resources like solar, batteries and demand response devices in concert, California ratepayers could be paid $500 to $1,000 per year while improving resource adequacy.

California Supreme Court to review rooftop solar net metering The state’s highest court granted review to a lawsuit challenging a “regressive” rooftop solar policy called NEM 3.0.

As more and more homeowners go solar, neighbors are increasingly wondering how they get on board the clean energy train. To help people get started, Pacific Northwest National Laboratoryn(PNNL) researchers have published an open-access guide to rooftop solar and BESS in Renewable Energy Focus, a journal of ScienceDirect. 

The PNNL researchers analyzed utility rates, net metering policies, installation costs, financial incentives and more. The guide is aimed at consumers, but is also useful for those in the industry, as it provides facts and figures that can help dispel misconceptions.

“We want to demystify this process of adding rooftop solar and battery energy storage,” said Kerby, an energy systems engineer at PNNL. “We want to empower people with the understanding of how this complicated system works.”

For utility customers thinking of putting in solar with a battery backup system, the guide explains how energy storage can be used to lower their electricity costs. For example, it explains the time of use structure, in which utilities charge more for electricity during times of high demand and less when demand decreases. Because the battery system can store the sun’s energy during the day, that energy can come from the battery in the evenings, when electric rates are highest.

Kerby notes that the rates for the off-peak times are always lower than the utility’s flat rate, while the on-peak times will be higher, so “that’s a huge opportunity for solar and storage.”

The guide also looks at the flip side, which is if the utility charges a flat rate for electricity, explaining that in this case a battery may not help the electricity customer to save on their bill. But Kerby notes that homeowners could use battery energy storage as a safety backup in the event of power outages.

The guide also tackles the topic of net metering and explains how, in some states, it can speed up the payback period of the solar investment.

“Depending on what state you live in, selling excess electricity production back to the utility could help recover the cost of solar panels and energy storage systems over time,” Kerby said. These policies are evolving, so make sure to review your state’s policy before making any decisions.

Five states are chosen as case studies to show the results of net metering policies, utility rate structure, and the average utility price. The five states include Massachusetts, Colorado, Rhode Island, Georgia and Tennessee.

The report authors point out that the differences noted between the states highlights the importance of state support for solar, and in some cases battery storage. Also noted are price signals because “benefits of residential renewable systems are best realized in states with net metering policies facing the challenge of above-average electric utility rates.”

A research report from Lawrence Berkeley National Laboratory found that 1,080 GW of solar projects and about 1,030 GW of storage projects await interconnection studies, so they may connect to the transmission grid.

Solar and battery storage accounted for over 80% of new capacity entering the queues in 2023, driving a 30% increase in the waiting lists, known as queues, for interconnection studies.

Storage capacity in the queues grew more than 50% last year. Over half of the battery storage capacity in the queues is paired with some form of generation, typically solar. Wind capacity in the queues rose to 366 GW, while only 79 GW of fossil gas and 2 GW of coal capacity await interconnection studies.

The values were nearly the same as preliminary values published last month in a staff report from the Federal Energy Regulatory Commission (FERC).

The growing backlog of projects awaiting grid interconnection studies “has become a major bottleneck” for project development, the study said, as proposed projects are “mired in lengthy and uncertain” interconnection study processes. Based on past experience, the study said that “most interconnection requests are ultimately cancelled and withdrawn,” while projects that are built are taking longer on average to reach commercial operation.

Although FERC adopted major interconnection reforms in 2023, the study says most reforms “have not yet taken effect in most regions, with project developers continuing to cite grid interconnection as a leading cause of project delays and cancellations.”

The authors pointed to other project development stages beyond submitting an interconnection request, and then waiting for the grid operator to complete interconnection studies, saying that “projects must also have agreements with landowners and communities, power purchasers, equipment suppliers, and financiers, and may face transmission upgrade requirements.”

Even so, the authors said that data from the queues provides a “general indicator for mid-term trends” in power sector activity and energy transition progress.

Berkeley Lab compiled and analyzed data from the seven organized electricity markets in the U.S. known as RTOs and ISOs, and an additional 44 balancing areas outside of RTOs and ISOs, which together represent over 95% of currently installed U.S. electricity generation.

Total generation plus storage capacity in the queues at year-end 2023 equaled 2.6 terawatts, as shown in the image below, which the authors noted is about eight times larger than the interconnection queue in 2014, and more than twice the current U.S. generating capacity of 1.28 TW.

Berkeley Lab has made available a study abstract, an overview and slide deck, an interactive visualization of the queue data, interactive maps and a data file.

The study’s authors will host a webinar to describe the research and answer questions on April 23 at 1 p.m. Eastern time.

From pv magazine Global

It is often said that LFP batteries are safer than NMC storage systems, but recent research suggests that this is an overly simplified view.

In the rare event of catastrophic failure, the off-gas from lithium-ion battery thermal runaway is known to be flammable and toxic, making it a serious safety concern. But while off-gas generation has been widely investigated, until now there has been no comprehensive review on the topic.

In a new paper, researchers from the University of Sheffield, Imperial College London, and the University of St Andrews in the United Kingdom have conducted a detailed meta-analysis of 60 papers to investigate the most influential battery parameters and the probable off-gas characteristics to determine what kind of battery would be least hazardous.

They have found that while NMC batteries release more gas than LFP, but that LFP batteries are significantly more toxic than NMC ones in absolute terms.

Toxicity varies with state of charge (SOC). Generally, a higher SOC leads to greater specific gas volume generation.

When comparing the previous findings for both chemistries, the researchers found that LFP is more toxic at lower SOC, while NMC is more toxic at higher SOC. Namely, while at higher SOC LFP is typically shown to produce less off-gas than other chemistries, at lower SOC volumes can be comparable between chemistries, but in some cases LFP can generate more.

Prismatic cells also tend to generate larger specific off-gas volumes than offer cell forms.

The composition of off-gas on average is very similar between NMC and LFP cells, but LFP batteries have greater hydrogen content, while NMC batteries have greater carbon monoxide content.

To assess the fire hazard of each chemistry, the researchers calculated and compared the lower flammability limit (LFL) of the off-gasses. They have found that LFL for LFP and NMC are 6.2% and 7.9% (in an inert atmosphere) respectively. Given the LFL and the median off-gas volumes produced, LFP cells breach the LFL in a volume 18% smaller than NMC batteries.

“Hence LFP presents a greater flammability hazard even though they show less occurrence of flames in cell thermal runaway tests,” the researchers said.

They discussed their findings in “Review of gas emissions from lithium-ion battery thermal runaway failure – Considering toxic and flammable compounds,” which was recently published in the Journal of Energy Storage.

Solar electric plus thermal systems to be manufactured in Texas  Naked Energy signed a deal with ELM Solar to manufacture its VirtuPVT and VirtuHOT systems in Dallas, with units available for purchase in 2025.

New Jersey farm studies agrivoltaics with vertically mounted solar Rutgers University reports that the vertical system fits well with the aim of the project, which is to study the benefits of agrivoltaics where there is a large energy demand and limited space.

Five energy equity policy wins in 2024  Advocacy group Vote Solar highlights policies it helped influence and develop in Q1 2024.

Long-duration energy storage innovators receive DOE funding  The Department of Energy Office of Electricity announced recipients of the $15 million in EarthShot funds directed to accelerate development, commercialization and use of next-generation energy storage solutions.

Rutgers University’s 170 kW agrivoltaic project on its farm on the Cook campus in New Brunswick, New Jersey features a vertical solar installation designed by California-based Sunstall.

The farm operates as a production farm, research facility and teaching operation in support of the Rutgers School of Environmental and Biological Sciences and Rutgers New Jersey Agricultural Experiment Station related activities. At the farm, students, faculty and staff care for a variety of animals, including sheep, goats and cattle.

Agrivoltaics refers to the dual use of land for agriculture and solar energy generation, and the Rutgers farm is an example of such dual use, where a forage crop will be planted and beef cattle will graze between rows of solar modules. The design includes animal shelters that provide a shade area, animal drinking facilities, and a handling chute for safely managing large animals. Rutgers reports that the objective is to study the impacts of the agrivoltaic system on forage production and animal grazing, including any behavioral changes the animals may exhibit when grazing among the panels.

Results from the project will contribute to the Dual-Use Solar Energy Pilot Program administered by the New Jersey Board of Public Utilities (NJBPU). The New Jersey Agricultural Experiment Station received $2 million from the state for building research and demonstration agrivoltaic systems on its Research Farms.

Sunstall chose New Jersey-based developer and EPC contractor Advanced Solar Products as the installer. The vertical racking system from Sunzaun will consist of 18 rows of 21 solar modules, mounted in rows running north to south, enabling the system to receive sunlight from east and west.

The Sunzaun vertical racking system will hold bifacial solar modules that produce energy from both sides of the vertically oriented array.

The project will use ZnShine 450 W bifacial solar modules with a bifaciality rating of 70%. The system is designed to mount the modules using holes in the module frames, enabling them to be attached to two piles without the need for a heavy racking system.

This is not the first Sunzaun vertical agrivoltaic system in the U.S. Another example can be found in a vineyard in Somerset, California, where Sunstall installed 43 450 W modules on Sunzaun vertical solar arrays.

Agrivoltaics have been found to have other benefits as well, such as reducing water evaporation from the soil. A research group led by the University of Liège in Belgium studied this and verified that the vertical PV system could reduce water demand for the irrigated main crops. In addition, agrivoltaics can help meet the U.S. clean energy goals. Research by Oregon State University found that solar and agricultural co-location could provide 20% of the total electricity generation in the United States. Wide-scale installation of agrivoltaics could lead to an annual reduction of 330,000 tons of carbon dioxide emissions while “minimally” impacting crop yield, the researchers said.

Water canals in California, Utah, and Oregon are soon to be outfit with solar panels, as three projects received federal funding through the Inflation Reduction Act (IRA). IRA set aside $25 million for the design, study, and implementation of photovoltaics co-located with water reclamation facilities.

The three projects will receive a combined $19.5 million to support the projects, which are administered by the Bureau of Reclamation, an agency tackling the challenges of water and power management in the U.S. West.

This IRA carve-out was created with input from California Representative Jared Huffman. The program directed to study the water efficiency gains from covering canals with solar panels.

Solar on canals is a use-case for photovoltaics that is expected to come with significant co-benefits for each technology. The panels provide shade for the water resources, reducing losses from evaporation. In turn, the water cools the solar panels, reducing operating temperature, which improves the efficiency of the panels and slows degradation of the equipment.

“Deploying solar panels on our canal systems is a smart solution to our growing water and energy dilemmas – it harnesses clean energy technology to increase efficiency while reducing our carbon footprint and water loss from canal evaporation,” said Representative Huffman.

The largest of the three projects, located in California, received $15 million through the fund. The San Luis & Delta-Mendota Water Authority will deploy floating solar arrays on the Delta-Mendota Canal. The University of California-Merced will study the project through a public-private partnership.

Researchers will deploy up to three varying floating solar technologies to assess the viability, costs, and benefits of floating solar over canals. The program will validate designs for PV on moving water and explore design and operational challenges associated with the emerging use-case.

A 2021 study conducted at the University of California, Merced and University, Santa Cruz, showed that covering the approximately 4,000 miles of public water delivery system infrastructure in California with solar panels can generate 13 GW of energy annually, equal to about one sixth of the state’s installed capacity and about half the projected new capacity needed to meet the state’s goal of reducing greenhouse gas emissions 40% by 2030.

The study modeled that 63 billion gallons of water could be saved annually by covering canals, which is enough to irrigate 50,000 acres of farmland or meet the water needs of more than 2 million residents.

The two other pilot projects are in Oregon and Utah. A $2.55 million-funded project in Oregon will float solar panels on the main canal of the Deschutes Project near Bend, Oregon.

In Utah, $1.5 million in funds are diverted to a project on the Layton Canal near West Haven, Utah. The five-year demonstration project will collect data on technical capabilities and economic feasibility for deploying solar canals at large scale.

In addition to improving PV performance and reducing evaporation, solar on canals is expected to minimize canal maintenance by reducing aquatic plant growth, create land use savings and preserve agricultural lands, and reduce the energy and carbon footprint of water reclamation facilities.

Through the Bipartisan Infrastructure Law, the Bureau of Reclamation is also investing $8.3 billion over five years for water infrastructure projects, including rural water, water storage, conservation and conveyance, nature-based solutions, dam safety, water purification and reuse, and desalination.

How much solar will be impacted by the solar eclipse points out how far solar has grown in the U.S. since the last eclipse in 2017. The Energy Information Administration (EIA) estimates that a combined 6.5 GW of solar capacity lies in the path of the full solar eclipse, also called the path of totality, with 84.8 GW that will experience the partial eclipse

“Total solar installations in the U.S. have increased threefold in the last seven years,” explained Guohui Yuan of the Solar Energy Technologies Office, which sponsors this study. “On a typical spring sunny day, solar photovoltaics will generate about 30% of the electricity used in Texas.”

The 2017 eclipse didn’t have much effect on solar energy production, however, solar contributed only 1.3% to the electrical grid at that time, according to the EIA. The EIA estimates that solar will provide 6% of U.S. electricity generation this year—a significant increase over 2017, and enough to cause some concern about the eclipse effect.

NREL researchers have calculated the following maximum power reduction from solar photovoltaics in the three interconnection regions:

• East: 71%
• West: 45%
• Texas: 93%

While Texas will experience the greatest overall reduction during the eclipse, the Eastern region’s power grid will be most affected due to the number of power plants on that region’s grid.

The researchers also modeled every independent system operator region and individual balancing areas (roughly on a utility-by-utility scale) across the country.

Maximum PV Reduction

“A systematic study of the impacts of the eclipse will provide valuable insights for grid operators across the country as they prepare for extreme weather events,” said Marilyn Jayachandran of the North American Electric Reliability Corporation, a collaborator on the study.

The sun will be partially covered in major metropolitan areas for up to 3.5 hours and many in total darkness for as much as four minutes, requiring system operators to be prepared to meet a fast generation ramp rate. However, other weather events require that system operators build in enough diversity to energy systems so that utility customers will be ensured that there will not be a power outage.

Load rebalancing

How will they do this? While the researchers expect solar energy to decrease by 35.3 GWh during the time of the eclipse, assuming mostly sunny conditions across the country, the load will be rebalanced primarily by pumped hydropower storage (42%) and hydropower (24%), along with gas (30%), and a combination of oil-gas-steam (2%), and steam (2%).

Battery storage will also play a role by using stored solar and wind generation and discharging it when needed. The Energy Information Administration (EIA) estimates that 15.4 GW of battery storage is installed today in the U.S., compared to only 0.6 GW in 2017 during the last eclipse.

The ramp rates during the eclipse are expected to be two- to three-times higher than typical dawn and dusk ramp rates, NREL reports.

The U.S. Department of Energy Solar Energy Technologies Office, the National Renewable Energy Laboratory (NREL), and the North American Electric Reliability Corporation are evaluating the grid impacts and NREL will provide a livestream via Zoom, beginning at 1:30 p.m. ET.

pv magazine USA will report on the research team’s post-event analysis and the mitigation measures taken by grid operators.

DOE funds heated sand energy storage project pilot  A modeled commercial-scale project storing energy in heated sand could produce 135 MW of power for five days. The U.S. Department of Energy is funding a pilot project intended to demonstrate commercial viability.

Off-grid solar bench with wireless charging and Wi-Fi A California university was provided off-grid solar powered benches by Bluebolt Outdoor.

Researchers discover additive that enhances perovskite coating process By adding an ionic pair stabilizer to perovskite cells enables coating to take place in ambient air, simplifying the manufacturing process.

Tigo Energy provides software and services for solar installation companies Installers participating in Tigo’s Green Glove program are guided from solar design through project commissioning.

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.

Researchers at the National Renewable Energy Laboratory (NREL) working on a multi-day energy storage system using heated sand have developed a prototype, shown in the featured image above, which has set the stage for a pilot demonstration project.

The sand used in the thermal energy storage (TES) system could be heated to the range of 1,100 degrees Celsius using low-cost renewable power. The nearby diagram shows that when electricity is needed, the system will feed hot sand by gravity into a heat exchanger, which heats a working fluid, which drives a combined-cycle generator.

Image: NREL

The NREL team’s computer modeling has shown that a commercial-scale system would retain more than 95% of its heat for at least five days, the national laboratory said in a news release.

The U.S. Department of Energy will provide $4 million to fund a pilot demonstration project sized with a 100 kW discharge capacity and a 10-hour duration, with groundbreaking set for next year at NREL’s Flatiron campus outside Boulder, Colorado. The pilot project is intended to show the technology’s commercial potential.

At commercial scale, when the sand is fully heated and stored in five silos, the technology could produce 135 MW of power for five days, according to an NREL report.

A targeted levelized cost of storage of 5¢/kWh could be achieved under a variety of scenarios, the report said.

“Building upon existing thermal power plants” would help facilitate a commercial path for the technology, the report said, while additional factors to improve economic returns “may include utility capacity payment, community benefits around retiring thermal power plants, and continuing decline of renewable electricity price.” In addition, “designing the system for dynamic operation (e.g., faster startup, option for gas addition) is likely to increase revenue by tapping into daily storage operation.”

NREL’s report said a technology-to-market transition plan has been developed for the TES system but was not included in the publicly available report “due to the business sensitivity of NREL and partners.”

Babcock & Wilcox, one of five project team members supporting NREL’s research, announced in 2021 that it had signed an agreement with NREL, which gave it “field-limited exclusive rights” to negotiate a licensing agreement that would allow it to market the technology.

Several other energy storage technologies have storage durations longer than the typical four-hour limit for battery storage. For example, Hydrostor is developing a 500 MW/4,000 MWh compressed air energy storage project in California. A pumped storage project under development in Montana would have a capacity of 400 MW and an estimated annual energy generation of 1,300 GWh. And flow batteries have a global market estimated by a research firm at $289 million in 2023.

For seasonal energy storage, hydrogen storage in salt caverns is an option. A project in Utah is expected to have a storage capacity of 150 GWh matched with an 840 MW hydrogen-capable gas turbine combined cycle power plant.

California pivots to propose $24 average fixed fee to electric bills  The Public Utilities Commission said the new billing structure will include a reduction of electricity rates by 5 to 7 cents per kilowatt hour.

Clean Energy Connector pilot launches in Illinois, New Mexico and Washington D.C. The software tool is designed to connect eligible households to community solar projects through the Department of Health and Human Services’ HHS’s Low-Income Home Energy Assistance Program (LIHEAP).

Environmental lifecycle assessment of PERC solar modules  IEA PVPS Task 12 analyzes the environmental impact of passivated emitter and rear cell (PERC) technology in PV installations in comparison to the monocrystalline silicon technology (AI-BSF) and the trend towards installing horizontal single-axis tracker systems as opposed to fixed tilt systems.

Solar module prices remain steady amid unchanged market fundamentals In a new weekly update for <b>pv magazine</b>, OPIS, a Dow Jones company, provides a quick look at the main price trends in the global PV industry.

The great untapped potential in non-residential rooftop solar for LMI residents The team used satellite imagery and AI to track unused rooftops with good solar potential, and found that it would bring reduced energy costs to residents.

U.S. solar industry week in review pv magazine USA spotlights news stories of the past week including market trends, project updates, policy changes and more.

According to a recent study, published in Nature Energy and led by researchers at Stanford University, commercial and industrial rooftop offer a great opportunity to reduce what researchers call the “solar equity gap.”

The gap exists because lower-income communities have historically been slower to adopt solar power than their affluent neighbors, even when local and federal agencies offer tax breaks and other financial incentives.

“The solar equity gap is a serious problem in disadvantaged communities, in part because of income inequalities, but also because residential solar isn’t usually practical for people who don’t own their homes,” said Ram Rajagopal, senior author of the study and associate professor of civil and environmental engineering and of electrical engineering at Stanford. “This new study shows that commercial and industrial properties have the capacity to host solar resources to fill in part of that gap.”

The researchers used satellite images and artificial intelligence to identify the number and size of rooftop solar arrays in 72,739 census tracts across the U.S., with about one-third of those tracts identified disadvantaged by the U.S. government.

The team tracked the amount of unused rooftops with good solar potential, then calculated the average annual cost of producing solar electricity in each area, based on the amount of local sun exposure and other variables. The costs ranged from about 6.4 cents per kWh in sun-drenched New Mexico to almost 11 cents in Alaska. Compare this to the 2022 electricity rate that was just over 20 cents per kWh in Alaska and about 10 cents in New Mexico, per Energy Information Administration data. The researchers noted that there would be additional costs of getting the power to residential areas as well as other costs, such as battery storage and the construction of microgrids.

“We estimate that battery storage would increase total system costs by about 50%, but even that would be practical in almost two-thirds of the disadvantaged communities we studied,” said Chad Zanocco, co-author of the study and a postdoctoral fellow in civil and environmental engineering.

The untapped rooftops offer great potential for community solar installations, which low-income residents could subscribe to. Community solar is a way for people to access solar energy who don’t own their own home or can’t afford the up-front cost of solar. Furthermore, the Inflation Reduction Act offers a bonus tax adder for community solar developers who build community solar projects in disadvantaged communities and have low-income subscribers.

“Beyond reducing carbon emissions and slowing climate change, increased access to solar power would offer tangible local benefits to lower-income communities,” said Zhecheng Wang, a co-author and a postdoctoral fellow at Stanford’s Institute for Human-Centered Artificial Intelligence. “This would promote local clean and low-cost energy generation, which would also increase the resilience from outages and reduce the pollution caused by fossil fuel power plants – many of which are located in low-income areas.”

On April 8, 2024, a solar eclipse will start on Mexico’s Pacific coast around 11:07 a.m. PDT, traveling across parts of the U.S. and Canada until 5:19 p.m. EDT. Because the sky will darken completely in the path of totality for up to six minutes, forecasters are looking at the potential effect on solar energy generation.

The last eclipse took place in the U.S. in 2017, and didn’t have much effect on solar energy production, however, solar contributed only 1.3% to the electrical grid at that time, according to the U.S. Energy Information Administration (EIA). The EIA estimates that solar will provide 6% of U.S. electricity generation this year—a significant increase over 2017, and enough to cause some concern about the eclipse effect.

Solcast, a solar modeling and forecasting company owned by DNV, reported that the impact on solar generation across the U.S. could be greater than any previous eclipse due to the increased solar power generation.

Solcast used its clear-sky irradiance modeling, assuming no presence of clouds or smoke. Due to ongoing growth in national solar capacity, the grid impact of such major solar events is increasing, and this eclipse will have greater impact on power generation than previous eclipses. The company forecasts that the overall effects of the eclipse will cost as much as 16% of daily total clear sky irradiance in some areas.

Grid operators are preparing for a worst-case scenario, which would be a perfectly sunny day when solar would normally be feeding steadily into the grid. In areas of in the path of totality, solar generation will decrease and then be cut to zero, only to ramp back up again a few minutes later.

According to Solcast, the maximum duration will be over 90 minutes of impacted generation and a total loss of up to six minutes. The effect across the country will be a faster “ramp rate” than normal, which is the rate at which solar generation decreases and then picks back up again.

Across all grids, Solcast estimates calculated maximum losses are up to 39.9 GWh, of which 16.2 GWh will be lost from household rooftop solar. “Whilst it’s too early to predict cloud impacts, the effects of this eclipse will be significant on solar generation across the country,” said Dr. Hugh Cutcher, lead Data Scientist at Solcast.

To compensate for potential loss of solar energy flowing to the grid, grid operators will have to be ready to rely on other sources to ensure grid stability, as was done during the 2017 and 2023 eclipse episodes.

Texas utility ERCOT, for example, is watching the event, as it provides power to 90% of the state and the state’s grid will be affected by the eclipse from 12:10 p.m. to 3:10 p.m. CDT, or during peak production hours. According to Solcast, ERCOT could experience a loss of nearly 11% of normal generation.

ERCOT posted on X that it is “working on forecasting models to reflect reduced solar power production (similar to a sunset and sunrise in the middle of the day) and does not expect any grid reliability concerns during the eclipse.”

Learning from the past

Looking back at the 2017 eclipse that obscured the sun for 76% of Northern California and 62% of Southern California on August 17, the EIA had estimated that more than 21 GW of installed photovoltaic (PV) systems would be affected. Utilities expected that production from solar plants would fall nearly 66%, with a sharp down ramp followed by an accelerated up ramp. To reduce “strain” on the electric grid, the California Public Utilities Commission President at the time urged residents to cut energy use between 9 a.m. and 11 a.m. on that day.

Because the ramping down and up had little deleterious effect, a call to curb electrical use is not likely to happen with the 2024 eclipse. In fact, during the 2017 eclipse, which also affected Georgia, Georgia Power “registered barely a blip”. Georgia Power had livestreamed the eclipse and watched solar power dip significantly for the three minutes of the eclipse’s totality and yet there was no failure to the grid.

Iron-based flow batteries have been around for decades, and some are now commercially available. While vanadium redox flow batteries are the most mature and popular technology in the family of flow batteries, adopting iron complexes as the active materials of choice could alleviate the challenges associated with the supply chain, particularly in the context of large-scale energy storage applications.

A new battery designed by researchers at the Department of Energy’s Pacific Northwest National Laboratory (PNNL) is said to provide a pathway to a safe, economical, water-based, flow battery made with abundant materials, while also offering strong performances.

The researchers have developed a liquid chemical formula that combines charged iron with a neutral-pH phosphate-based liquid electrolyte. They used the chemical called nitrogenous triphosphonate, nitrilotri-methylphosphonic acid (NTMPA), which is commercially available in industrial quantities and typically used to inhibit corrosion in water treatment plants.

Phosphonates, including NTMPA, are a broad chemical family based on the element phosphorus. Many phosphonates dissolve well in water and are nontoxic chemicals used in fertilizers and detergents, among other uses.

“We were looking for an electrolyte that could bind and store charged iron in a liquid complex at room temperature and mild operating conditions with neutral pH,” said senior author Guosheng Li, a senior scientist at PNNL who leads materials development for rechargeable energy storage devices. “We are motivated to develop battery materials that are Earth-abundant and can be sourced domestically.”

The researchers reported that their lab-scale, iron-based battery exhibited remarkable cycling stability over one thousand consecutive charging cycles, while maintaining 98.7% of its capacity. For comparison, previous studies of similar iron-based batteries reported degradation of the charge capacity two orders of magnitude higher, over fewer charging cycles. The new battery also demonstrated high Coulombic efficiency and energy efficiency near 100% and 87%, respectively, they said.

“A BESS facility using the chemistry similar to what we have developed here would have the advantage of operating in water at neutral pH,” said Aaron Hollas, a study author and team leader in PNNL’s Battery Materials and Systems Group. “In addition, our system uses commercially available reagents that haven’t been previously investigated for use in flow batteries.”

The research team reported that their initial design can reach energy density up to 9 Wh/L, lagging behind commercialized vanadium-based systems that are more than twice as energy dense, at 25 Wh/L. Their next move is to improve the battery’s voltage output and electrolyte concentration, which will help to increase the energy density.

Their results were discussed in the study “Phosphonate-based iron complex for a cost-effective and long cycling aqueous iron redox flow battery,” published in nature communications.

From pv magazine Global

An international research team has investigated the effect of inverter clipping on mitigating soiling losses in PV systems and has found that this strategy may not be as effective as commonly thought.

Inverter clipping occurs when a PV system’s DC energy is larger than the maximum input size of the inverter. This saturates the inverter and the excess DC energy is not converted into AC.

“Because of this masking effect, inverter undersizing has often been suggested as a practical soiling mitigation strategy,” the research group stated. “Indeed, the soiling losses are not visible from the AC side during clipping if they are not bigger than the difference between the energy rating of the modules and the capacity of the inverter.”

In the paper “Quantifying the impact of inverter clipping on photovoltaic performance and soiling losses,” published in Renewable Energy, the scientists explained that their theoretical work aimed at answering the typical question that PV modelers and soiling experts are often asked: “Isn’t inverter clipping enough to mitigate the effects of soiling on photovoltaic systems?”

People on the move: SunPower, University of Houston, and more Job moves in solar, storage, cleantech, utilities and energy transition finance.

Schneider Electric and Mainspring offer multi-fuel microgrid solution Schneider Electric’s EcoStruxure Microgrid Solution can be paired with Mainspring Energy’s Linear Generator to produce and store carbon-free energy for continuous use.

Evaluating the profitability of vanadium flow batteries Researchers in Italy have estimated the profitability of future vanadium redox flow batteries based on real device and market parameters and found that market evolutions are heading to much more competitive systems, with capital costs down to €260/kWh at a storage duration of 10 hours.

Electrolyzer prices – what to expect In addition to the cost of electricity, the price of hydrogen depends largely on the up-front investment cost of the electrolyzer. The lower the full-load hours, the greater the impact. Analyst BloombergNEF (BNEF) sees a number of different possible pathways for the market to develop.

Report tracks emerging PV manufacturing hubs in Europe, North America Sinovoltaics is studying the changes in the supply chains in manufacturing hubs in Europe and North America to determine site capacity, current and planned, for dozens of manufacturers. The results are being published in free reports.

JinkoSolar claims top spot in 2023 PV module shipment rankings Chinese manufacturer JinkoSolar says its solar module shipments reached 78.5 GW in 2023. This year, it says it hopes to sell up to 110 GW of panels.

Longi denies massive layoff plan, says job cuts could reach up to 5% Chinese solar manufacturer Longi has responded to recent media reports claiming that it might cut 30% of its global workforce.

Booming U.S. energy storage installation grows 90% year-over-year Lowered costs, easing supply chains and steady demand continued the energy storage boom, said a report from Wood Mackenzie.

From pv magazine Global

Vanadium flow batteries are one of the most promising large-scale energy storage technologies due to their long cycle life, high recyclability, and safety credentials. However, they have lower energy density compared to ubiquitous lithium-ion batteries, and their uptake is held back by high upfront cost.

Now, researchers led by the University of Padua in Italy developed a techno-economic model, using experimental and market data, which can better inform investment decisions for this type of technology.

Their model considers the present and future competitivity of industrial flow batteries in operating specific services, which have not yet been developed to an accurate grade, and yields economic performance indicators such as capital costs, operative costs, levelized cost of storage (LCOS), and net present value.

To perform their calculations, the researchers used technical parameters taken from large-area multi-cell stacks, rather than from small single-cell experiments, to better characterize the behavior of real industrial-scale systems. They also used data from real financial markets and economic patterns of some major manufacturers.

The assessment was performed considering a lifespan of 20 years with a charge/discharge cycle per day. Each component affecting the capital and operative costs was analyzed, and the impact of side phenomena on capacity losses was considered.

As a result, their model showed where the economic indicators are heading and which parameters have a greater affect on investment profitability, thus tracking a possible roadmap for system optimization.

Their estimations indicate that technological and market evolutions are heading to much more competitive systems, with capital costs down to $284.2  per kWh at an energy/power duration of 10 hours. Namely, this is the breakeven point where the present values of total costs equate the present values of total revenues and no economic result is obtained.

“This is to be compared with a break-even point in the net present value of $434 per kWh, which suggests that flow batteries may play a major role in some expanding markets, notably the long duration energy storage,” the researchers stated.

Their results are published in the study “Techno-economic assessment of future vanadium-flow batteries based on real device/market parameters,” which was recently published in Applied Energy.

Slowing distributed energy growth continues into 2024 Ohm Analytics reported that the 2.3 GW of distributed generation, which includes rooftop solar, deployed in Q4 2023 marked the end of a long period of growth. Roth MKM warns that if a turnaround does not occur soon, residential solar could decline by 20% to 30% in 2024.

Fluke introduces I-V curve tracer for utility-scale solar industry By adding the PVA-1500 Series I-V curve tracer to its portfolio, Fluke now offers tools for solar professionals servicing everything from the distributed generation to the utility-scale.

Vehicle-integrated photovoltaics for electric ground transport  Canadian custom module manufacturer Capsolar developed a vehicle integrated PV system (VIPV) for an electric material towing application, reportedly enabling 30% to 40% range increase per battery charge.

Solar can help with marijuana’s green problem Indoor cannabis growth was estimated to use 1% of all U.S. electricity consumption back in 2012, before any states had legalized it. This number has grown like a weed, creating an opportunity for solar to decarbonize operations.

Maryland community solar install to take just nine weeks due to unique mounting Using Erthos mounting system, which places panels directly on the land with no racking or trackers, the project is expected to be installed rapidly and save on land use.

Research from Australia suggests that employing electric vehicle-to-grid (V2G) connections at a 10% penetration rate can reduce peak demand charges for local substations by 6% and substantially lower fueling costs for electric vehicle (EV) owners. However, without proper management, EV penetration levels above 20% could negate those benefits.

The study, ‘Network tariffs for V2G,’ conducted by enX and commissioned by the Australian Renewable Energy Agency, aimed to explore the interaction between dynamic electricity and network tariffs (which are real-time, similar to wholesale pricing tools) and the increasing number of EVs connecting to the grid. The study also sought to understand how these EVs could help alleviate grid pressure in comparison to fixed time-of-use tariffs.

Findings indicate that V2G connections under dynamic pricing, specifically tariff types s3 & s6 in the chart above, led to the greatest substation peak demand shaving. These same dynamic pricing tariffs also saved significant amounts on EV owners’ electricity bills, with some V2G participants earning a net positive revenue on their vehicles’ electricity use, including one small account that covered 100% of their overall electricity use.

The analysis examined the load at the Metford substation in New South Wales, Australia, specifically focusing on one of the highest peak demand days of the year, March 6, 2023. On this day, the maximum peak demand reached 41.6 MW at 6pm. Under a dynamic pricing electricity and network tariff focused on peak shedding, the substation experienced a reduction of 2.54 MW in peak load. This reduction accounted for 6.29% of the substation’s peak demand value.

The analysis also found that an early morning peak is developing and expected to reach a high-stress point as V2G EVs hit a 20% uptake rate.

The dynamic pricing model achieved the most significant reduction in peak demand when applied to both network charges (including transmission, distribution, and demand-type charges) and electricity pricing. This model priced electricity based on current market rates, contrasting with time-of-use pricing that relies on fixed periods of higher and lower rates.

The analysis also revealed that a combination of bidirectional network support tariff and spot passthrough pricing (scenario s5) resulted in a reduction of 2.11 MW, nearly matching the 2.54 MW in savings from the optimal model. Models s3, s5, and s6 all generated significant savings for their car owners, as well as significant peak shaving for the substation.

In total, the analysis modeled 520 unique user accounts, including customers with solar power installations of varying sizes and diverse patterns of electricity usage. The study was motivated by projections for the year 2050, which predict a significant increase in EV battery capacity. According to the document, EV battery capacity is expected to reach approximately 2.4 TWh, four times the estimated power grid storage capacity of 0.64 TWh. The researchers emphasize that unlocking the potential of these batteries will be crucial for optimizing the power grids of the future.