Longi has revealed plans to enter the inverter business through a partnership with Shenzhen Energy, while Solarspace has announced plans to open a 16 GW cell factory in Anhui province.
Longi and Shenzhen Energy have set up a joint venture to open an inverter factory in Xuzhou, Jiangsu province. The two companies will invest CNY 5.3 billion ($791 million) in the new facility, which will have a capacity of 10 GW and could also potentially host 10 GW of solar module production.
Solarspace has signed a deal with the government of Chuzhou, Anhui province, for a 16 GW solar cell manufacturing facility. The factory will be built in two 8 GW phases and produce cells based on 182 mm and 210 mm wafers. The total investment is CNY 10.5 billion. Solarspace has currently a cell production capacity of 19 GW and 4.5 GW of module production.
Energy China, one of the largest state-owned energy enterprises in China, has submitted a project proposal for a huge PV and concentrated solar power (CSP) complex in Xuzhou, in China’s Xinjiang region. The plant will consist of a 1.35 GW solar array, a 150 MW CSP unit, and an unspecified amount of storage capacity.
Xinte Energy said it expects a net profit of CNY 5.5 billion to CNY 6 billion for the first half of this year. Last week, the manufacturer said that its solar and wind project development margins had increased, along with polysilicon prices.
Researchers from the Swiss Center for Electronics and Microtechnology (CSEM) and the École polytechnique fédérale de Lausanne (EPFL) claim to have achieved a power conversion efficiency exceeding 30% for a 1 cm2 tandem perovskite-silicon solar cell, which they said represents a world record for a PV device of this kind.
In particular, they achieved an efficiency of 30.93% for a 1 cm2 solar cell based on high-quality perovskite layers from solution on a planarized silicon surface and an efficiency of 31.25% on a cell of the same size and fabricated with a hybrid vapor/solution processing technique compatible with a textured silicon surface.
“These results constitute two new world records: one for the planar and one for the textured device architecture,” they specified, noting that both efficiencies were certified by the US Department of Energy’s National Renewable Energy Laboratory (NREL). “The latter approach provides a higher current and is compatible with the structure of current industrial silicon solar cells.”
Schematics of perovskite-on-silicon tandems that are either flat or textured on their front side.Image: C. Wolff (EPFL)
The research team did not disclose technical details on how they improved the efficiency of both devices.
“These high-efficiency results will now require further R&D to allow their scaling up onto larger surface areas and to ensure that these new cells can maintain a stable power output on our rooftops and elsewhere over a standard lifetime,” said CSEM researcher Quentin Jeangros. “Our results are the first to show that the 30% barrier can be overcome using low-cost materials and processes, which should open new perspectives for the future of PV,” the researchers added.
The previous world record — of 29.8% — had been achieved by scientists from the Helmholtz Center Berlin (HZB) in Germany in November 2021. This result improved upon the previous world record achieved by perovskite developer Oxford PV in December 2020, when the UK-based company announced a power conversion efficiency of 29.52% for its perovskite/silicon tandem device.
EPFL researchers achieved 29.2% efficiency for a tandem solar cell with fully textured silicon measuring 1 cm2 in April. This result was confirmed by Germany’s Fraunhofer Institute for Solar Energy Systems ISE. “A big challenge will be developing solar cells that can remain stable on our rooftops for more than 25 years. But the higher efficiency we demonstrated without changing the front texture will be very attractive for the photovoltaics industry,” said EPFL scientist Christophe Baliff at the time.
Longi’s solar cell achieved a fill factor of 86.08%. Image: Longi
Germany’s Institute for Solar Energy Research Hamelin has confirmed that Longi’s new n-type heterojunction solar cell has achieved a power conversion efficiency of 26.5%.
Chinese PV module maker Longi has achieved a power conversion efficiency of 26.5% for an n-type heterojunction (HJT) solar cell based on indium and an M6 wafer. It said the result has been confirmed by Germany’s Institute for Solar Energy Research Hamelin (ISFH).
“Through consistent technological innovation, Longi, the world’s leading solar technology company, has achieved continual breakthroughs in PV conversion efficiencies, breaking the world record for HJT cell efficiency twice in one week in October 2021,” it said, without providing additional details. The cell also achieved a fill factor of 86.08%, it noted.
Longi achieved an efficiency of 25.47% for a p-type cell in March and a 25.19% rating for its p-type TOPCon solar cell in July 2021. In June 2021, it recorded a 25.21% efficiency rating for an n-type TOPCon device. It has also reached a 26.3% efficiency for its n-type HJT cell.
French researchers have developed PV modules with an area of 11.6 square centimeters for indoor applications. They said the achieved efficiency level marks a world record for a flexible perovskite device larger than 10 square centimeters.
Researchers at France’s National Solar Energy Institute (INES) – a division of the French Alternative Energies and Atomic Energy Commission (CEA) – have developed new flexible perovskite solar modules.
They have a surface area of 11.6 square centimeters, with a maximum power conversion efficiency of 18.95% and a stabilized efficiency of more than 18.5%. INES said the performance is a world record for a flexible perovskite device larger than 10 square centimeters.
Currently, the power conversion efficiencies of solar devices based on perovskites indeed exceed 25% for single junctions and 29% in tandem structures with silicon. However, these results are obtained on small surfaces, of the order of 1 square centimeters.
To obtain this yield on larger surfaces, INES developed the flexible perovskite solar modules at low temperature on low-cost substrates made of polyethylene terephthalate (PET). They used a very simple structure featuring five layers, including the electrodes.
The performance is obtained after encapsulation and the stability of the devices has been tested under damp heat conditions at 85 C, according to the standards used for silicon-based technologies. A stability of several hundred hours has been obtained – between 400 and 800 hours, depending on encapsulation – based on a standard objective of 1,000 hours.
To achieve this result, the CEA optimized the stacking of the layers of the cell to implement a three-step laser process for the production of the module. It also developed a flexible encapsulation process that is fully compatible with high gas barrier materials, with no initial loss.
The CEA’s devices will be integrated into a demonstrator for building-integrated photovoltaic (BIPV) applications by Flexbrick (Es), a member of the European consortium. The modules will be interconnected to obtain high voltages and will be tested according to building standards. In addition, stability tests in real conditions are currently being carried out.
The Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) in Germany, a project partner, is testing the panels for indoor applications. The tests have already shown power conversion efficiencies of up to 24.5% at very low light (500 lux).
For some applications, the use of flexible substrates could be of interest for single-junction perovskite technology, because it could open the way to high-speed and low-temperature printing processes. It therefore becomes possible to use low-cost substrates unlike flexible inorganic technologies, such as CIGS, which require higher temperature processes and more expensive substrates.
Many teams around the world are trying to meet the challenges of making larger devices with sufficient stability for real-world applications. This is one of the tasks set by the partners of the European APOLO project.
The Renewable Energy Test Center (RETC) has released its “2022 PV Module Index” (PVMI) report, highlighting module performance across a variety of lab tests, while also providing industry-cited clarifications on the real-world significance of the results.
The 2022 PVMI marks the first edition released since VDE acquired a 70% stake in RECT. President and CEO Cherif Kedir said the move will allow RETC to expand its testing services to a broader network of manufacturers, investors, insurers and developers, all in pursuit of minimizing risk and uncertainty in favor of long-term reliability, sustainability and profitability by designing better data-driven risk mitigation programs and service products.
RETC Vice President of Business Development Daniel Chang told pv magazine the 2022 PVMI takes a more forward-looking approach than previous editions, supplementing testing results and hardware performance with emerging industry trends that are going to guide the use of this hardware and investments in projects that utilize it into 2023 and beyond.
Cherif Kedir, President and CEO of RETC
“We focus on what we think are going to be topics that are going to be relevant for the upcoming year, like the onset of N-Type modules, and field services,” explained Chang. “There are a lot of installations out there degrading at a faster pace than expected. These installations are investments in assets made by banks to yield some sort of financial benefit to them, right? If they have some sort of degradation, then that’s not performing the way that was expected and planned for.”
Specifically, RETC is interested in forensic analysis of PV systems to determine the root causes of underperformance. This investigation is the culmination of different analyses to be done over the life of a project, starting with a baseline third-party module health assessment during project commissioning.
In instances of underperformance, RETC recommends Electroluminescence (EL) testing. EL testing uses a special camera system to document the light emissions that occur when an electrical current passes through PV cells. The technology has long been used in labs to detect a wide range of hidden module defects.
Another aspect of forensic analysis is predictive maintenance, wherein a third party inspects plants from periodically to detect issues that may not be visible at a base overview, but could develop into much larger issues if allowed to linger.
While Chang brought to light the ongoing issue of degradation and the developing need for advanced field services, Kedir focused more on the technology side, researching where the next wave of module innovation will come in a post-large-format world.
Panasonic Heterojunction with Intrinsic Thin Layer (HIT) solar cell
That innovation, he thinks, will come from heterojunction n-type modules (HJT).
“I think leading manufacturers are kind of a crossroad point right now, in terms of how to get more power out of modules without making the modules just unreasonably large, because they’re already pretty damn big,” Kedir said. “The other reason I think manufacturers may be hesitant to make their modules larger is that everybody is testing the waters with heterojunction cells, so that they can eke out more more watts per module, without having to increase the size. With the module technologies they currently have, I don’t think they’re able to get a lot more efficiency out of the cell, so they’re trying to figure out how to get more power without increasing the module size, and the next, the next logical thing is to go to different technologies, Topcon and heterojunction.”
In an op-ed for pv magazine in November 2021, Nadeem Haque – chief technology officer at Heliene – outlined some of the distinct technology advantages that HJT presents. HJT cell manufacturing involves the deposition of an amorphous layer of silicon on both the top and bottom of the wafer followed by a transparent conducting oxide deposition and making of metal contacts.
HJT cell production lines are currently expensive, almost prohibitively so, and new lines need to be built. The cells require a more expensive metallization paste to manufacture. HJT cells are by nature bifacial, with bifaciality rates above 90%, the highest of any cell technology. Higher bifaciality and lower temperature coefficients result in higher energy output, and HJT cells in mass production are expected to reach about 27% efficiency.
“You can gauge where the industry is going based on where investment money is going, and we hear a lot about companies investing money in heterojunction cell lines in Asia, so I think that’s probably going to be a trend,” said Kedir.
The last industry trend examined by RETC is mitigating the effects of extreme weather on PV systems, a topic which pv magazine has reported on extensively with RETC and other partners, like VDE Americas.
Module index
The core of the report is a review of modules’ performance across a range of tests that are designed to go beyond the parameters of tests for certification and accurately project what each module’s strengths are, rather than compare and rank them against one another.
The tests are split up into three categories, each of which analyzes a different aspect of module excellence: quality indicators, performance indicators, and reliability indicators. In testing, the researchers at RETC noticed a new trend that some of the performance and reliability gaps from manufacturer to manufacturer have widened, as opposed to the narrowing they observed in recent years.
“Some of the issues that we saw over the last year have been related to manufacturers faced with their own supply chain issues and inability to get their raw materials,” explained Kedir. “They’ve had to go to other sources, secondary and tertiary sources of cells and backsheets, and then that triggered a few failures, we saw more of them last year. What’s been lingering is potential-induced degradation (PID) and some related performance stuff. On cells, PID, for all intents and purposes, had been completely solved a few years ago, but then it reappeared throughout the pandemic, with the supply chain issues, we see some of that leftover.”
This is a phenomenon that Kedir expects to see continue, at least in the short term. The issue may linger as a result of the recently-announced two year moratorium on the DOC’s anticircumvention case, he said.
“Demand is going to is going to pick up in the US,” he began. “The upcoming traceability requirements are going to put a constraint on the cell supply from forced labor regions, which means you’re not going to have enough cell supply for them for the market demands. This causes supply separation between manufacturers. Some larger manufacturers have already completely mitigated that issue, developed a new supply chain for polycrystal, and have new cell lines in Southeast Asia. Those guys are going to fare out much better than a manufacturer who hasn’t put in that infrastructure already. They’re going to have to try to source cells from other places or other manufacturers that may or may not be as good as their initial supply.”
While the gap between top-tier, established module manufacturers and some newer market entrants is widening, RETC still had a number of manufacturers perform well across their litany of tests.
Based on available testing data, RETC highlighted Hanwha Q CELLS, JA Solar, and LONGi Solar as the overall top three performers of the year. The recognition does not stop with the top performers, however, and RETC listed some of the manufacturers who scored the highest marks in individual tests, listed below.
Hail durability:
LONGi Solar
Thresher test:
Hanwha Q CELLS
JA Solar
LONGi Solar
Tesla
LeTID resistance:
Hanwha Q CELLS
Jinko Solar
LONGi Solar
Trina Solar
LID resistance:
Hanwha Q CELLS
JA Solar
Jinko Solar
LONGi Solar
Trina Solar
Module efficiency:
JA Solar
LONGi Solar
REC Solar
Silfab Solar
Tesla
Yingli Solar
Pan file performance:
JA Solar
Jinko Solar
LONGi Solar
Trina Solar
PTC-to-STC ratio
Hanwha Q CELLS
JA Solar
REC Solar
Silfab Solar
Tesla
Yingli Solar
Damp heat test
JA Solar
LONGi Solar
Hanwha Q CELLS
Tesla
Dynamic mechanical load test:
JA Solar
Jinko Solar
LONGi Solar
PID resistance:
JA Solar
Jinko Solar
LONGi Solar
Thermal cycle test:
Hanwha Q CELLS
JA Solar
Jinko Solar
LONGi Solar
Tesla
RETC said the rankings are comprehensive only to data that the company has collected, so modules from other manufacturers could perform similarly to the ones listed above, but the organization cannot make an overall determination regarding high achievement in manufacturing without module tests data across the three categories.
The report concludes with a look at a number of notable changes and revisions anticipated in the upcoming edition of IEC 61730, a two-part standard pertaining to PV module safety qualification, as well as upcoming updates to IEC TS 62915, a technical specification pertaining to PV module approval, design and safety qualification.
The standards analysis is expansive, and pv magazine will cover these pending changes in a follow-up to this article.
Image: Hong Kong University of Science and Technology, Advanced Science, Creative Commons License CC BY 4.0
A research team in Hong Kong has built a solar window that can generate power on the external side via a luminescent solar concentrator and thermal energy on the internal side via transparent solar absorbers.
Scientists from the Hong Kong University of Science and Technology have developed a dual-band selective solar harvesting (SSH) window based on transparent photovoltaics (TPVs) and transparent solar absorbers (TSAs). The TSAs are used to convert ultraviolet (UV) or near-infrared (NIR) light by converting it into thermal energy.
“The harvested thermal energy is extracted by ventilated air to provide indoor space heating in cold seasons or abate indoor cooling loading in hot seasons,” they explained. “We demonstrated that the SSH window has a visible transmittance of 42%, achieves a solar-electricity conversion efficiency of 0.75%, and a solar-thermal conversion efficiency of 24% with a ventilated air temperature rise of 10 C.”
The research group used a luminescent solar concentrator (TPV) based on copper indium sulfide and zinc sulfide (CuInS2/ZnS) quantum dots (QDs) as the exterior window. It is able to collect UV light and convey it to opaque PV devices that are located at the edge of the transparent substrate for electricity generation. The TSAs were instead used to fabricate the interior side of the window where heat is produced and collected.
“The thermal energy is mostly extracted by the ventilated air within the gap for various purposes such as indoor space heating in cold seasons,” the group said.
The academics fabricated a prototype measuring 30 cm x 30 cm x 2.4 cm by assembling the TPV elements with the TSAs on the interior side. They claim the device showed a substantial visible transmittance and that it was able to generate 6 W per square meter of power and the thermal power of around 150 W per square meter.
“Thermal power is 25 times of the generated electrical power, suggesting that the harvesting thermal power is of primary importance for building-integrated solar energy harvesting windows,” they said. “With thermal energy harvesting by air ventilation, the total effective efficiency was estimated over 30% at a typical operating condition for building space heating applications.”
“The SSH window can save the annual heating, ventilation, and air conditioning (HVAC) energy consumption by up to 61.5% compared with the normal glass, in addition to the generated electricity that accounts for up to 19.1% of the annual energy saving amount,” they said.
A recycled glass panel on the front and a linen composite on the back. Image: GD
French solar energy institute INES has developed new PV modules with thermoplastics and natural fibers sourced in Europe, such as flax and basalt. The scientists aim to reduce the environmental footprint and weight of solar panels, while improving recycling.
Researchers at France’s National Solar Energy Institute (INES) – a division of the French Alternative Energies and Atomic Energy Commission (CEA) – are developing solar modules featuring new bio-based materials in the front and rear sides.
“As the carbon footprint and the life cycle analysis have now become essential criteria in the choice of photovoltaic panels, the sourcing of materials will become a crucial element in Europe in the next few years,” said Anis Fouini, the director of CEA-INES, in an interview with pv magazine France.
Aude Derrier, the research project’s coordinator, said her colleagues have looked at the various materials that already exist, to find one that could allow module manufacturers to produce panels that improve performance, durability, and cost, while lowering the environmental impact. The first demonstrator consists of heterojunction (HTJ) solar cells integrated into an all-composite material.
“The front side is made of a fiberglass-filled polymer, which provides transparency,” Derrier said. “The rear side is made of composite based on thermoplastics in which a weaving of two fibers, flax and basalt, has been integrated, which will provide mechanical strength, but also better resistance to humidity.”
The flax is sourced from northern France, where the entire industrial ecosystem is already present. The basalt is sourced elsewhere in Europe and is woven by an industrial partner of INES. This reduced the carbon footprint by 75 grams of CO2 per watt, compared to a reference module of the same power. The weight was also optimized and is less than 5 kilograms per square meter.
“This module is aimed at the rooftop PV and building integration,” said Derrier. “The advantage is that it is naturally black in color, without the need for a backsheet. In terms of recycling, thanks to thermoplastics, which can be remelted, the separation of the layers is also technically simpler.”
The module can be made without adapting current processes. Derrier said the idea is to transfer the technology to manufacturers, without additional investment.
“The only imperative is to have freezers to store the material and not to start the resin cross-linking process, but most manufacturers today use prepreg and are already equipped for this,” she said.
The INES scientists also looked into the solar glass supply issues encountered by all photovoltaic players and worked on the reuse of tempered glass.
“We worked on the second life of glass and developed a module made up of reused 2.8 mm glass that comes from an old module,” said Derrier. “We have also used a thermoplastic encapsulant which does not require cross-linking, which will therefore be easy to recycle, and a thermoplastic composite with flax fiber for resistance.”
The basalt-free rear face of the module has a natural linen color, which could be aesthetically interesting for architects in terms of facade integration, for example. In addition, the INES calculation tool showed a 10% reduction in the carbon footprint.
“It is now imperative to question the photovoltaic supply chains,” said Jouini. “With the help of the Rhône-Alpes region within the framework of the International Development Plan, we therefore went looking for players outside the solar sector to find new thermoplastics and new fibers. We also thought about the current lamination process, which is very energy intensive.”
Between the pressurization, the pressing and the cooling phase, the lamination usually lasts between 30 and 35 minutes, with an operating temperature of around 150 C to 160 C.
“But for modules that increasingly incorporate eco-designed materials, it is necessary to transform thermoplastics at around 200 C to 250 C, knowing that HTJ technology is sensitive to heat and must not exceed 200 C,” said Derrier.
The research institute is teaming up with France-based induction thermocompression specialist Roctool, to reduce cycle times and make shapes according to the needs of customers. Together, they have developed a module with a rear face made of polypropylene-type thermoplastic composite, to which recycled carbon fibers have been integrated. The front side is made of thermoplastics and fiberglass.
“Roctool’s induction thermocompression process makes it possible to heat the two front and rear plates quickly, without having to reach 200 C at the core of the HTJ cells,” Derrier said.
The company claims the investment is lower and the process could achieve a cycle time of just a few minutes, while using less energy. The technology is aimed at composite manufacturers, to give them the possibility of producing parts of different shapes and sizes, while integrating lighter and more durable materials.
An international research group led by Professor Martin Green from the University of New South Wales in Australia has published Version 60 of “Solar cell efficiency tables” in Progress in Photovoltaics.
The scientists said they have added 15 new results to the new version of the tables since January. They also noted that an appendix describes new approaches and terminology.
Since 1993, when the tables were first published, the research group has seen major improvements in all cell categories.
“Copper, indium, gallium and selenium (CIGS) and multijunction cells have seen the most consistent gains, although perovskites have recently seen similar overall gains compressed into a shorter timescale,” Green told pv magazine in an interview last year.
He said that the most important factor for inclusion in the tables is that all results should be independently measured at test centers on the group’s list.
“All of our recognized test centers are carefully vetted prior to inclusion on our list and have been involved in round-robin testing with one another, ensuring consistency of measurements to well within the uncertainty estimates included with the published results,” said Green.
The research group includes scientists from the European Commission Joint Research Centre, Germany’s Fraunhofer Institute for Solar Energy Systems, Japan’s National Institute of Advanced Industrial Science and Technology, the US Department of Energy, and the US National Renewable Energy Laboratory.
Module maker JinkoSolar announced this week it secured a solar module supply agreement from Chinese property development company Datang Group. The order relates to the supply of 1 GW of n-type TOPCon bifacial modules with a power output of up to 560 W for use in large scale projects.
Module manufacturer Risen said on Thursday that its CNY 5 billion ($758 million) private placement of shares has been suspended for a month. The net proceeds from the transaction should be devoted to the construction of a new solar module factory that still needs to get final approval from the China National Development and Reform Committee (NDRC).
China’s Shandong Province announced this week that its fourteenth five-year plan spanning 2021 to 2025 envisages deploying at least 65 GW of PV capacity by the end of 2025, including at least 12 GW of offshore PV for which a specific tender was issued last month. The provincial authorities have already identified 10 offshore sites along Shandong’s coast where the projects could be constructed. Binzhou, Dongying, Weifang, Yantai, Weihai and Qingdao are some of the preferred areas.
Shunfeng International’s proposed sale of four solar projects has collapsed. The heavily-indebted developer announced in January plans to sell 132 MW of solar generation capacity to state-owned entity State Power Investment Group Xinjiang Energy and Chemical Co Ltd to raise CNY 890 million ($134 million). After postponing four times publication of details of the shareholder vote required to approve the sale, Shunfeng this week said the deal had fallen through. The transaction was complicated by the Changzhou Intermediate People’s Court of Jiangsu Province in April, which granted a freezing order on the 95% stake in one of the solar project companies held by a Shunfeng subsidiary. The order was granted at the request of two investors in a 2015 Shunfeng bond who claim money is owed them by the developer. “The board will explore other opportunities to dispose of … some or all of the target companies in order to improve the financial position of the company,” Shunfeng told the Hong Kong Stock Exchange this week.
The REC Alpha Pure-R Series is available in three versions.Image: REC
REC’s new heterojunction solar panel series features efficiencies of up to 22.3% and an operating temperature coefficient of -0.26% per degree Celsius.
Norway-based PV module manufacturer REC has launched a residential heterojunction solar module based on 12G wafers and gapless technology at the Smarter E event in Munich, Germany. It has raised the density of the panels by eliminating the empty spaces between the cells.
“REC’s advanced gapless cell connections allow to increase power while keeping the panel compact,” the company’s head of global PR, Agnieszka Schulze, told pv magazine. “In addition, it eliminates soldering for better build quality and reduces cell stress for long-term durability.”
The REC Alpha Pure-R Series is available in three versions, with power ratings ranging from 410 W to 430 W, and efficiencies of 21.2% to 22.3%. The new product is made with 80 heterojunction, half-cut monocrystalline solar cells and its maximum system voltage is 1,000V.
The open-circuit voltage is between 55.8 V and 56.3 V and the short-circuit current ranges from 7.12 A to 7.24 A. All three versions of the solar module measure 1,730 mm × 1,118 mm ×30 mm and weigh in at 21.5 kg.
The panel can be used with operating temperatures ranging from -40 C to 85 C and the operating temperature coefficient is -0.26% per degree Celsius. It is enclosed between 3.2 mm solar glass with anti-reflective treatment, and also features a junction box with an IP 68 rating, a black polymer backsheet, and an anodized aluminium frame.
The manufacturer offers a 20-year linear power output guarantee and a 25-year product guarantee. It said the module series is eligible for the premium REC ProTrust warranty package, which offers up to 25 years coverage on product, performance and labor, with a guaranteed power of at least 92% in year 25 of operation.
“Featuring heterojunction (HJT) cells in the large G12 format in a patented panel design, REC’s newest product delivers power output of up to 430 Wp, while keeping the module under twom² in area,” the manufacturer said in a statement. “This makes the new product ideal for residential installations where space is limited.”
The company will start production of the REC Alpha Pure-R module at its facility in Singapore in August.
“The new product will be sold in all REC markets across the US, Europe and Asia-Pacific,” a company spokesperson said.
