“I was not surprised by the figure itself but by the trend,” Bartosz Majewski, CEO of solar distributor Menlo Electric, told pv magazine. “As a distributor, we have decided to limit inventory as much as possible, in anticipation of the upcoming winter and the price drop that happened at the beginning of July. Even though the prices are decreasing since Q4 last year, they have then been sliding gradually through Q1 and Q2, but in Q3 the prices dropped by 30% in China – this is what really caught many distributors by surprise.”

Majewski said Menlo reduced its module inventory by a factor of 2.5 between July and the end of September.

“Now we are well below our one month's worth of sales,” he explained. “Rystad probably worked on different substocks or categories. For example, if modules are sold from Chinese manufacturer to their European subsidiary, or a distributor, under Cost, Insurance and Freight (CIF) incoterms, then they are formally exported the moment they are loaded on the ship. This is why they may appear that as European “stocked“ modules, even though they are still at sea and haven’t reached Europe yet. It takes roughly six weeks for these panels to come to Europe. So, if you assume that the Chinese are exporting 8 GW to 10 GW per month, that would mean that there would be about 10 GW to 15 GW worth of stock at sea, not in warehouses.”

“We do have some clients that have purchased significant stocks in anticipation of this season and some of them are still going through these stocks, although it is already October.”

Filip Sypko, general manager key accounts at Menlo Electric, that the tens of gigawatts of stored solar power in Europe primarily serve residential and commercial installations.

Most of the modules stored in Europe are based on PERC technology, with the result that the related market segment, mostly residential and C&I installations, is highly saturated.

“There is much oversupply and is very difficult to make positive margins there,” Majewski said. “For n-type products, it is a bit different, as it is still possible to make some positive margins.”

According to Majewski, n-type is currently only €0.01 more expensive than p-type.

“For p-type, it doesn’t matter at what price it was purchased, but at what price the buyer is willing to buy. All these modules in European warehouses will have to be sold by the end of this year, which means that regardless of what was the purchase price in the market, people will try to sell at the current market price because they need to release cash to pay their bills. For many companies it will be a matter of survival,” he said. For this reason, these stocked modules, especially those relying on p-type technology, may now be offered at a lower price than new arrivals from China.

When the bottom will be reached is unclear and installers will not wait indefinitely.

“You can wait, wait and wait but some installation just need to be delivered by the end of the year,” Majewski said.

Majewski believes there will be a limit to further module price drops in the months to come.

If you look at the margins made by the polysilicon and wafer manufacturers, and at those made by module makers, you realize that panel producers have not benefitted that much from the upward trend of the last two years. It was mostly the polysilicon and wafer manufacturers that captured windfall profits,” he said. “Now, however, both polysilicon and wafer producers are largely operating close to their marginal cost. So, it means that there is not too much potential for the prices to go significantly down further. They may continue to slide slowly but not as quickly as we have seen in Q3 2023.”

Reduced moisture in the Amazon delivered clear skies and increased irradiance across the tropics of South America. Solar assets in the region saw 110-120% of average monthly irradiance through September.

A strong and slow-moving storm early in the month lessened irradiance in southern Brazil, but the rest of mid-latitude South America saw mostly normal irradiance, according to data collected by Solcast, a DNV company, via the Solcast API. The Altiplano Plateau saw the highest irradiance for the whole continent. This is in line with historical averages, as the area records some of the highest irradiance levels in the world.

In September the tropics saw higher irradiance than usual. This was due to clearer skies caused by the current drought in the Amazon. The northeastern part of the Amazon has been dry since mid-July, resulting in reduced moisture in the rainforest and less evapotranspiration. This is a major source of moisture fuelling cloud formation over rainforest regions.

The region saw regular cumuliform clouds typical of tropical regions, but not the large storms and rainfall events that are typical of the start of the wet season in September. The rivers in the Amazon are reported to be at their lowest level in over a century as there has been a lack of rainfall and ensuing dry conditions in recent months. This has been exacerbated by warm conditions, as South America recorded the warmest September extending from heatwaves.

The Brazilian southern states of Rio Grande de Sul and Santa Catarina saw reduced irradiance. It recorded 10-20% below September averages and is due to an unusually strong extra-tropical cyclone. The storm moved onshore from the Atlantic in early September, and it’s slow-moving nature meant the irradiance impacts were more focussed and intense. Most of the remainder of mid-latitude South America saw much more moderate irradiance at or slightly below the long-term average.

Solcast produces these figures by tracking clouds and aerosols at 1-2km resolution globally, using satellite data and proprietary AI/ML algorithms. This data is used to drive irradiance models, enabling Solcast to calculate irradiance at high resolution, with a typical bias of less than 2%, and also cloud-tracking forecasts. This data is used by more than 300 companies managing over 150 GW of solar assets globally.

Chinese solar cell and module maker Aiko Solar has introduced three new solar modules at the Fintec tradeshow, which took place this week in Barcelona, Spain.

The company said its AIKO-A-MAH72Mw, AIKO-A-MAH54Mw and AIKO-A-MAH54Mb modules all rely on its proprietary all-back-contact (ABC) solar cell technology.

“The main advantages of our technology are the entirely illuminated cell area, the electrodes behind, the all passivated rear contacts and silver-free metallization,” Carolina Calisalvo, Head of Marketing Iberia, told pv magazine.

The manufacturer offers the AIKO-A-MAH72Mw in five versions with power output ranging from 600 W to 620 W and efficiency spanning from 23.2% to 24.0%. The open-circuit voltage is between 53.94 V and 54.34 V and the short-circuit current is between 13.44 A and 13.76 A. It has a size of 2,278 mm x 1,134 mm x 35 mm and a weight of 28.2 kg.

The AIKO-A-MAH54Mw module is offered in four versions with an output of 450 W to 465 W and an efficiency of 23.0% and 23.8%. The open-circuit voltage is between 40.50 V and 40.80 V and the short-circuit current is between 13.44  A and 13.7 A. It measures 1,722 mm x 1,134 mm x 30 mm and weighs in at 20.5 kg.

As for the AIKO-A-MAH54Mb panel, it is an all-black product featuring an efficiency ranging from 22.8% to 23.6% and an output of 445 W to 460 W. The open-circuit voltage is between 40.60 V and 40.90 V and the short-circuit current is between 13.86  A and 14.04 A. It has dimensions of 1,722 mm x 1,134 mm x 30 mm and a weight of 20.5 kg.

All products are built with 3.2 mm tempered anti-reflective glass and aluminum alloy frames. They also feature an IP68 enclosure and a maximum system voltage is 1,500 V. The panels have a temperature coefficient of -0.26% per degree Celsius and an operational temperature ranging from -40 C to 85 C.

Aiko Solar provides a 30-year performance warranty, with a purported 1% degradation in the first year and a guaranteed end power output of no less than 88.85% of the nominal power after 30 years.

A group of scientists from South Korea's Rural Development Administration, an agriculture organization under the country's Ministry of Agriculture, has created an energy system based on photovoltaic-thermal (PVT) panels and a ground-source heat pump.

The system is intended to provide cooling and heating to greenhouses.

“In Korea, geothermal energy is widely used as renewable energy for agriculture, but if geothermal heat is used for a long time, the heat source becomes insufficient,” the agency said, noting that covering around 10% of the greenhouse's roof with PVT panels may easily compensate for this typical shortcoming of geothermal energy. 

The researchers said the PVT panels are able to produce hot water at temperatures ranging between 30 C and 40 C. “This is then used as a heat source for the heat pump to produce hot water at temperatures ranging from 48 C to 50 C, which is a suitable range for greenhouse heating,” they explained.

In spring, summer, and fall, when heating is not needed, the heat produced by the PV panels is sent to the groundwater layer, stored, and used to heat the greenhouse in winter.

The PVT system used in the project has an overall efficiency of 73% and is able to achieve an electricity output of 3 kW and a heat output of 7.9 kW of heat occupying a roof surface of around 18㎡. The presence of the PVT panels, according to the research group, allowed them to reduce the installed capacity of the existing geothermal system by up to 30%.

The researchers conducted an economic analysis of the system performance and found it may reduce heating and cooling costs in a greenhouse by up to 78% compared to diesel generators. They also estimated that the system may achieve a payback time of 4.4 years. “The PVT panels can increase the energy saving rate of a greenhouse by 20% compared to existing geothermal systems,” the researchers added.

The Rural Development Administration said it has applied for a patent for this technology and plans to distribute it to Korean farmers.

“The price of electricity for agricultural use is rising, putting a huge burden on farm management,” said the agency. “We are actively using new and renewable energy such as solar power, heat, and geothermal heat to reduce the costs and achieve carbon neutrality.”

North American manufacturer Ecoflow has launched a “retrofit” residential battery solution that it claims can be easily integrated with existing rooftop PV arrays.

“Unlike conventional DC-coupled or AC-coupled battery systems, PowerOcean DC Fit uses EcoFlow's PV-coupling technology to directly connect with existing home solar energy systems on the PV side – meaning users don't need to install additional storage inverters,” the manufacturer said in a statement.

The battery uses lithium iron phosphate (LiFePo4) as the cathode material and is based on a self-adaptive algorithm that the manufacturer said makes the system compatible with most of the existing solar single-phase and three-phase inverters that are already in use in existing PV installations.

“Using EcoFlow's unique PV-coupling technology, the PowerOcean DC Fit connects its batteries directly with solar panels. Users can leave the AC wiring as it is and don't have to apply for an on-grid permit,” the company stated.

The storage system measures 680 mm x 183 mm x 479 mm and weighs 59.2 kg. It has a capacity of 5 kWh and is expandable to 15 kWh. It also features an output voltage range of 150-800 V and a maximum output current of 20 A.

The new product is IP65-rated and reportedly has a lifecycle of more than 6,000 cycles.

“Each battery pack is connected parallelly and equipped with the EcoFlow BMS (Battery Management System) to prevent one battery's issues from affecting other packs,” the manufacturer said, noting that the new product comes with a 15-year warranty.

A group of researchers led by China's Nanjing University has created a global-scale inventory map to determine the spatio-temporal distribution of floating photovoltaics.

“Existing statistical reports on water-surface photovoltaics (WSPV) only provide aggregated summary statistics but lack spatiotemporal information, which hinders the environmental assessment and policy management,” the research's lead author, Shanchuan Guo, told pv magazine. “We developed a new and adaptive workflow for identifying WSPV using satellite imagery and integrating multiple spectral indices.”

In the paper “Mapping global water-surface photovoltaics with satellite images,” published in Renewable and Sustainable Energy Review, the research group explained it combined multi-source data and mapping results to assess the geographic distribution and characteristics of WSPV s and produce an an up-to-date spatial database.

The water mask was based on the global surface water dataset (GSW) created by the European Union's Joint Research Centre (JRC), which provides the annual spatial distribution of surface water from 1984 to 2020.

“WSPVs are spectrally distinct from most land cover types and can be identified by remote sensing once they are larger than the satellite pixel size,” the scientists specified. “We used Google Earth images and Sentinel satellite imagery from 2019 to 2021 to examine and modify the type changes of WSPV validation samples over three years, and finally obtained the annual correctly labeled validation samples.”

The academics claim that the proposed approach enables the mapping of WSPVs over large areas at high resolution. They found that the water areas covered with floating PV installations increased from 187.0 km2 to 272.0 km2 between 2019 and 2021. They also estimated estimated a global installed WSPV capacity of 12.9 GW.

“The results advanced the understanding of the global spatial-temporal dynamics of the recent WSPV development and will be useful for informing future global and regional renewable planning and management for policymakers and project stakeholders,” they stressed.

The research group also hosted scientists from Michigan State University and the Shanghai Jiaotong University.

MVV Energie AG has switched on an industrial heat pump at a coal-fired power plant operated by Grosskraftwerk Mannheim AG (GKM) in Mannheim-Neckarau, Germany.

The German energy supplier said the new system is integrated into a district heating network and is one of the largest such systems in Europe. The heat pump uses water from the Rhine River and has a thermal output of 20 MW. It will provide heating for 3,500 households. Siemens Energy supplied the heat pump technology and GKM integrated it into the infrastructure of the large power plant for MVV Energie.

MVV Energie said that the water of the Rhine River in Mannheim is up to 25 C in summer and only around 5 C in the winter. This thermal energy is sufficient to evaporate the refrigerant in the heat pump and reduce the temperature of the Rhine River water by around 2 C to 5 C.

The refrigerant vapor is then compressed using an electrically powered compressor to increase the pressure and temperature. The heat generated by the refrigerant vapor is transferred to the district heating water through condensation in a heat exchanger, producing hot water at temperatures ranging from 83 C to 99 C.

The refrigerant liquefies and expands again in the heat exchanger. It then cools down and absorbs thermal energy from the river water at a low temperature to restart a new cycle.

“The heat pump works on the same principle as the home refrigerator,” MVV Energie said in a statement. “While the heat energy of the refrigerator is released from the inside to the outside, the heat pump uses the heat to heat the district heating water.”

The project is part of the “Large heat pumps in district heating networks” initiative, which is funded by the Germany Ministry for Economic Affairs and Climate Protection (BMWK),

“The MVV project shows that heat pump technology also works in XXL format to provide climate-neutral supply to entire city districts,” said Thekla Walker, the minister of energy for the German state of Baden-Württemberg. “The river heat pump is an important building block for our country in reducing its dependence on fossil fuels step by step.”

A group of researchers from the National University of Sciences & Technology (NUST) in Pakistan has developed a PV system fault forecasting technique based on variations in solar cell current and voltage parameters.

“Existing fault detection techniques detect faults after their occurrence,” the research's lead author, Ihsan Ullah Khalil, told pv magazine. “Our proposed fault forecasting technique forecasts the fault so that predictive maintenance can be assured. It uses the rate of change of solar cell parameters to identify which fault is occurring.”

According to Khalil, solar cell parameters start changing even before a fault occurs. “The IV curve is divided into 172,000 data points, so we get 172,000 values of I and V,” he further explained. “Then, by using each value of I and V, and the values of Im and Vm, we extract the same number of values for each solar cell parameter. Finally, we model the rate of change of each variable for the first 100 data points. For the first hundred data points, I and V are almost the same up to the first decimal point.”

The proposed algorithm is claimed to be able to extract cell parameters at either no faulty conditions or faulty conditions and to sense fault at its inception level.

Machine learning-based regression techniques are used for the model, which the scientists said is able to detect variation trends of each parameter against each fault at the inceptive stage. The algorithm initially models the initial trend against a single voltage, current, and power value. It then splits the data set and models the variation of solar cell parameters using four variants of linear regression. “Linear regression has given excellent results,” Kahlil said. “One of the major contributions is introducing a lemma for the fault index formula that is not been discussed in the literature before.”

The scientists claim that the results demonstrate that the solar cell extraction method they used offer superior performance compared to existing forecasting techniques, as it analyzses the variation in cell current and voltage for the detection of faults at an incipient stage. “The significance of the proposed algorithm rests in its early fault detection capability, which contributes to the development of adaptive protection systems for photovoltaic installations,” stated the researchers.

Their findings were introduced in the study “A novel procedure for photovoltaic fault forecasting,” published in Electric Power Systems Research.

Researchers at the University of Science and Technology of China have developed a new system design for spectral-splitting concentrator agrivoltaics (SCAPV)

The system is based on the spectral separation of sunlight based on the difference in the spectral response of photovoltaics and photosynthesis. According to this principle, red and blue wavelengths are used for photosynthesis as they match the absorption peaks of plant chlorophyll, while all other wavelengths are used for concentrated power generation.

In the study “Large-scale and Cost-efficient Agrivoltaics System by Spectral Separation,” published in iScience, the scientists explained that the proposed system utilizes a dual-axis tracking technology with concentrator modules that optimize the cell components and the concentrating curve.

The 10 kW system occupies a surface of 400 m2 and consists of 128 concentrator modules, each integrating an ultra-white and toughened concentrating curved glass (CCG), a multilayer polymer film (MPF), which the researchers said is the key component for achieving spectral separation. Furthermore, 23%-efficient interdigitated-back contact (IBC) crystalline silicon solar cells with a concentration ratio of 6% were provided by Sunpower.

“These cells were cut into 1/3 strip PV cells (41 mm × 125 mm) and then connected in series using ethylene vinyl acetate (EVA) along with PV glass and a backboard, resulting in the formation of PV modules consisting of 24 such strip PV cells,” the scientists said, noting that solar cells with a higher concentration ratio would have resulted in higher system costs. Their selection process also took into account the spectral shift characteristics of the MPF, processing cost, module size, and holder height.

The concentrator photovoltaic panel consists of a back side receiving concentrated sunlight from the concave screen and a front side receiving direct sunlight. The tracking system uses two motors to control the angle of the spotting module for both azimuth and altitude angle tracking.

“The concentrator modules on the entire main beam square tube are driven via a drive shaft,” the researchers explained. “Integral brackets on the lower part of the concentrator module support the weight of the concentrator modules and wind/snow loads, and the weight is transferred to the primary beam through the north-south swing arm rotation shaft and the swing arm weldment.”

The SCAPV system was placed horizontally at a height of 2.5 m to allow small farm machinery to pass below it.

The system was tested in outdoor conditions in Anhui, China, and was found able to produce 107 MWh of electricity per hectare. Its overall system efficiency reached 11.6%, which the scientists said is the highest efficiency ever recorded for the spectral separation technology.

“Field planting experiments showed that five crops (ginger, peanut, sweet potato, bok choy and lettuce) had an average yield increase of 18.4% under SCAPV compared to open-air systems,” stated the research group. “The microclimate at the bottom of the SCAPV system, especially the soil moisture retention capacity in the daytime, was better than in the open air.”

The scientists believe that the costs of the system may decrease by 18.8% if around 1 GW of SCAPV capacity is deployed globally. They noted that the cost of the MPF currently accounts for around 50% of the system costs.

“Nevertheless, the laboratory's four-pronged plan – mass production of an autonomous film processing process, optimization of mechanical structures, development of lightweight modules, and the realization of scale effect – points towards heightened economic viability,” they concluded.

The Internal Market and International Trade Committees of the European Parliament have approved and amended a draft regulation against forced labor prepared by the European Commission. The proposal covers all products and does not target specific companies or industries.

“The draft regulation would put in place a framework to investigate the use of forced labor in companies’ supply chains,” the European Parliament said. “If it is proven that a company has used forced labor, all import and export of the related goods would be halted at the EU’s borders and companies would also have to withdraw goods that have already reached the EU market.”

The members of parliament approved the draft regulation and also made amendments. For instance, the revised version now requires companies operating in high-risk areas, rather than public authorities, to demonstrate that they do not use forced labor.

It also says that prohibited products can re-enter the EU market if the related producer can prove they have ceased using forced labor in their operations or supply chain. The committees also harmonized the definition of forced labor with the International Labour Standards.

“The ban that we have voted for today will be essential in blocking products made using modern slavery and taking away the economic incentive for companies to engage in forced labor,” said co-rapporteur Samira Rafaela. “It will protect whistle-blowers, provide remedy to victims, and defend our businesses and SMEs from unethical competition.”

The European Solar Manufacturing Council (ESMC), which recently urged the European Union to adopt legislation against forced labor in the PV industry, welcomed the vote. However, it said that it is concerned that it will take too long time until the legislation is enforced.

“We are afraid it will not be as effective as needed,” the association said in a statement.

The ESMC is an industry association that was created in 2019 with the aim of promoting the interests of the European PV manufacturing sector.

Taipower, a state-run utility in Taiwan, has created a new bidding platform to sell renewable energy to small and medium-sized businesses.

“A single bidder may choose between six different packages according to their own needs,” Taipower said in a statement.

Netherlands-based Triple Solar BV has launched a thermal battery for residential applications.

The manufacturer said the thermal storage system can be used in combination with its heat pumps. “Compared to a traditional hot water boiler, the thermal battery is up to four times smaller,” it said in a statement.

Triple Solar sells the new product in three different sizes. The smallest battery measures 640 mm x 365 mm x 575 mm and weighs 136 kg. It features a heat loss rate of 0.67 kWh/day and its capacity is 167 l.

The medium-sized device has a size of 870 mm x 365 mm x 575 mm, a weight of 187 kg and a capacity of 217 l. It has a heat loss rate of 0.77 kWh/day. The largest product has dimensions of 1,050 mm x 365 mm x 575 mm and weighs in at 233 kg. Its capacity is 333 l and it has a heat loss rate of 0.84 kWh/day.

All products operate at a maximum pressure of 10 bars and can reportedly provide hot water at temperatures ranging from 45C to 55 C, with minimum heat source temperature ranging between 65 C and 80 C.

“Households and their homes are becoming smaller and smaller. As a result, there is often no room for a large boiler,” said the company's COO, Cees Mager. “The thermal battery is so compact that it even fits in a kitchen cupboard.”

Triple Solar began selling the new thermal battery on October 12. The Dutch company also manufactures heat pumps and photovoltaic-thermal (PVT) panels.

US-based startup Wavr LLC has developed a wave energy converter (WEC) that could be used for low-power marine applications.

Wavr developed its first prototypes for consumers, such as boat owners. The company claims that the system is particularly suitable for water surfaces with weak waves, as its modular design is able to increase the required power output by integrating more systems in an array configuration.

The technology can be used in low-power marine data buoys and internet of things (IoT) devices, according to the company, which claims its technology has no intermittency issues found in some other renewable energy technologies.

“The system is also designed to be scaled up and integrated with other renewable energy technologies,” the company said, noting that future prototypes may also be combined with photovoltaic panels installed on top of the floaters, small wind turbines, mini-hydropower systems or other tidal energy technologies.

“We feel the hybrid unit with solar panels is the next most important prototype for us. We are currently developing it with a group called Infrgy,” the company's founder, Clyde Igarashi, told pv magazine. “We’re using conventional PV panels rated at IP68 to handle conditions out at sea. The panels are placed directly on top of the WEC modules and cables are protected by rubber seals. Micro inverters under the panels are used to synchronize with the frequency and amplitude of our wave energy converter.”

The standalone system is made of 3D-printed plastic and has a weight of 4.5 kg. It embeds an internal battery to store energy and is linkable to external batteries, the manufacturer said. It features a power output of 3 W per square foot (0.09 m2).

“After we perfect the hybrid Wavr with solar panels, the next step would be to link arrays together,” Igarashi said. “Currently we are targeting a price of around $2,300, which would include five 40 W solar panels. The 200 W solar system with inverter accounts for approximately $800 of the cost.”

He also stated that the price should decrease significantly with scale. “We haven’t yet done an LCOE calculation for any specific location,” he added.

Wavr is based in Mililani, Honolulu County, Hawaii.

Researchers led by the University of North Carolina at Chapel Hill have fabricated a large-area perovskite-silicon tandem solar cell. They claim iz can achieve a steady-state power conversion efficiency of 25.1%.

They said they tried to overcome shunting, which is a typical issue when scaling up perovskite solar technologies from small-area cells to large-area devices. “Shunts” in PV cells create alternate pathways for a solar-generated charge, leading to power losses. Reduced shunt resistance is associated with multiple forms of module degradation and failure, including hotspots and potential-induced degradation.

The scientists built the 24 cm² tandem cell with a lithium fluoride (LF) interlayer placed at the interface between a hole transport layer (HTL) made of poly-triarylamine (PTAA) and a wide bandgap (WBG) perovskite absorber. This interlayer is the key element that reportedly improves physical contact at the buried interface and mitigates shunting. The deposited the PTAA and WBG perovskite layers through blade coating.

“Sub-optimal interface contact with substantial voids could act as shunting pathways,” the scientists said. “A LiF interlayer was found to avoid the formation of interfacial voids, which is one possible reason for the reduced shunting of etched tandems with a LiF interlayer.”

The researchers deposited the other layers of the tandem cell by sputtering, thermal evaporation, and atomic layer deposition (ALD). They also tested three different configurations of bottom cells and opted for using

Tested under standard illumination conditions, the 24 cm² tandem cell showed an efficiency of 25.2%, an open-circuit voltage of 1.89 V, a short-circuit current density of 18.1 mA/cm² and a fill factor of 0.736.

“This is, to the best of our knowledge, one of the most efficient two-terminal tandem devices reported in the literature with areas of over 10 cm²,” the researchers said.

They introduced the tandem cell technology in “Shunt mitigation toward efficient large-area perovskite-silicon tandem solar cells,” which was recently published in Cell Reports Physical Science.

“The strategy developed here is valuable for developing efficient, reproducible, and large-scale perovskite-silicon tandems,” the scientists said.

Scientists at the University of Applied Sciences and Arts of Southern Switzerland have developed a novel hail test for photovoltaic panels that considers the impact of large, high-velocity ice balls.

The research team stressed that traditional hail tests conducted by the IEC 61215-2 standard usually assess the impact of ice balls with a 25 mm diameter and 80 km/h speed. It also said, however, that the Swiss Association of Cantonal Fire Insurers – the Vereinigung Kantonaler Feuerversicherungen (VFK) – established a minimum requirement of 30/40 mm and added that Switzerland's SUPSI PVLab is currently planning to create a hail test stand to reach 100 mm in diameter and 166 km/h in speed.

“The increase in ice ball diameter necessitates the evaluation of sample preparation, repeatability, and representativeness, as well as the ability to handle high speeds with high masses to reduce uncertainty in impact energy, as required by the Swiss standards,” the researchers said.

They utilized a Hopkinson bar, and a 30 mm aluminum bar to analyze the waveform resulting from the collision of the ice balls. They also used a strain-gauge station, a gas gun for ice ball acceleration, and a camera for fast image recordings.

The gas gun was designed to shoot ice balls with diameters of 25 mm, 40 mm, and 70 mm onto the Hopkinson bar. “A round plexiglass tube with different inner diameters was used to guide the spherical ice inside of it,” researchers explained. “To measure the velocity of the spherical ice specimens, a laser sensor was placed at the end of the tube.”

The academics shot the three balls at the same velocity and at two different frozen temperatures, −5 C and −20 C, to compare loading versus time response.

Analyzing the samples having 40 mm diameters, they ascertained that the temperature decrease caused a double loading rate, which in turn caused a higher stress rate on the bar.

“In the case of 25, 40, and 70 mm ice balls at −20 C, peak forces are approximately 70%, 59%, and 44% higher than those at −5 C at the same velocities,” they further explained. “For 25, 40, and 70 mm, ice reaches its peak force in a shorter amount of time at −20 C, which is 30%, 21% and 2% lower than at −5 C.”

The analysis showed that lower temperature results in a higher peak force and a shorter peak time. “Using these preliminary results, the project will move forward with its future tasks, including the analysis of hail stone damage using a multispectral camera, the analysis of PV panels of different ages, ice mechanical characterization in the same strain rate range, and FEM modeling of phenomena,” the scientists concluded.

Their findings were presented in the study “Advanced characterisation of photovoltaics for hail resistance,” published in Materials Letters. 

Mibet, a Chinese mounting system supplier, has introduced the MRac Waterproof solar carport solution, featuring a patented waterproof design to ensure excellent water resistance.

The “MRac Waterproof” design ensures waterproofing through its inherent structure, using surface-component structures for drainage. The upper rail support components are secured by side pressure blocks and middle pressure blocks, with aluminum alloy cover plates placed between component connections and EPDM single-ply roofing membrane strips installed.

“This tight component connection structure can block most rainwater,” a spokesperson from the company told pv magazine.

The carport also relies on a dual-track design at the bottom of the components for bidirectional water leakage prevention.

“Horizontal gutters are used on the upper level to direct excess water into the main gutter, which then guides the surplus rainwater to the drainage gutter,” the spokesperson said. “This ingenious multi-structural approach effectively addresses leakage concerns and achieves comprehensive waterproofing.”

The carport structure allows for the installation of both framed and unframed solar panels, offering a tilt angle ranging from 5 degrees to 15 degrees, in either portrait or landscape configuration.

According to Mibet, the carport mountings can be constructed from materials such as aluminum alloy, magnesium-aluminum-zinc, and carbon steel, demonstrating the capability to withstand 1.2 KN/m2 snow loads and 45 meters per second wind loads under standard conditions.

“Mibet's carport mountings are pre-assembled before leaving the factory, eliminating the need for cutting and welding on-site,” the spokesperson said. “Installation is completed by tightening bolts, significantly reducing construction time and lowering installation costs for users.”

The product comes with a 10-year warranty and is certified by TÜV Rheinland and SGS.

Researchers at the Indian Institute of Technology Mandi (IIT-Mandi) have designed a bifacial perovskite solar cell for indoor environments that use multiple artificial lighting sources.

“Indoor bifacial photovoltaics (i-BPVs) offer the potential to surpass traditional monofacial photovoltaics (i-MPVs) in terms of power output per single cell, all without significantly increasing manufacturing expenses and while occupying less space,” the research's lead author, Ranbir Singh, told pv magazine. “We have developed i-BPV cell based on perovskite that can efficiently harvest maximum artificial indoor light from both the front and back sides of the modules.”

Singh and his research group described the solar cell in the study “Indoor bifacial perovskite photovoltaics: Efficient energy harvesting from artificial light sources,” published in Solar Energy.

They built the device with a semi-transparent substrate made of glass and indium tin oxide (ITO), an electron transport layer (ETL) relying on tin(IV) oxide (SnO2), a MAPbI₃ perovskite layer,  a spiro-OMeTAD hole transport layer, and a semi transparent electrode made of gold (Au) and ITO. 

The scientists explained that the electrodes were designed to maintain transparency and improve artificial light harvesting from both sides. “For different Au/ITO layer thicknesses, the transmission decreases significantly with increasing Au layer thickness from 5 nm to 30 nm,” they added. Furthermore, they noted that the multilayer electrode (Au/ITO) exhibits a “good amount” of transmittance in the 450 nm to 800 nm wavelength range where most of the indoor light spectrum exists.

The researchers tested the bifacial cell under 1,000 lux LED light illumination and found it achieved a power conversion efficiency of 30.3%, an open-circuit voltage of 0.93 V, a short-circut current density of 148.3 μA/cm2 and a fill factor of 71.7%.

“The cell achieves a remarkable power output per single cell of 152.01 µW/cm²,” Singh stated. “Theoretical calculations suggest that bifacial devices have the potential to double the power generation at a 50% lower cost compared to their monofacial counterparts.”

According to the research team, the bifacial devices also showed a significant reduction in non radiative recombination losses, lower hysteresis and better operational stability in ambient air conditions compared to conventional monofacial PV structures. “The champion bifaciali cells display an excellent bifaciality factor of 0.73 and demonstrated superior operational stability when subjected to continuous illumination,” it also stated.

A group of scientists led by Germany's Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) have sought to apply for the first time the shingling interconnection technology to perovskite-silicon tandem (PVST) solar cells.

“The combination of PVST cells with shingling allows boosting the module efficiency even further due to the increase of the photoactive area through the absence of cell gaps,” the research's lead author, Veronika Nikitina, told pv magazine. “Technologically, shingling suits the temperature limitations of the PVST cells since the main factor for the choice of the processing temperature is the curing conditions of the electrically conductive adhesive.”

Shingled 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.

“A significant advantage of combining PVST cells and shingling is the relaxed requirements on finger resistivity due to the relatively low cell current density,” the scientists said. “Additionally, shingling does not utilize ribbons and requires only one cell side to be printed with electrically conductive adhesives (ECAs).”

They also stressed that shingling utilizes less material while lowering thermomechanical stress in the panels. It also increases a cell's active area, thus raising the device's fill factor and power conversion efficiency. Furthermore, shingled solar modules have an improved shading resilience compared to non-shingled products.

The researchers used M6 (166 mm x 166 mm) precursors with a two-terminal (2T) configuration provided by solar perovskite specialist Oxford PV. Metallization with low-temperature silver paste by means of screen printing deploying 60 fingers and continuous busbar took place at Fraunhofer ISE whereas cutting the cells into 1/5 shingles with 24.5% efficiency was realized at Oxford PV’s plant in Brandenburg, Germany. Shingles were shipped back to Fraunhofer ISE in Freiburg for interconnection and module integration.

“The optimum number of fingers on the front side was determined by sweeping number of fingers while keeping the number of fingers at the rear side as well as finger dimensions and busbar dimensions constant,” they also explained, noting that they utilized cell-to-module (CTM) analysis to assess the impact of the number of fingers and shingle size on the module efficiency.

Through their analysis, the academics found that the 1/6 cut PVST cells with 25 % initial shingle cell efficiency would be able to achieve a module efficiency of 23.4 %.

“The feasibility of the shingling approach as well as module integration with PVST cells was demonstrated by producing full-format modules,” the group said, adding that it produced real bifacial glass-glass solar panels based on industrial production equipment, which reached efficiencies of up to 22.8 %. “Metallization of PVST precursors with low-temperature silver paste by means of screen-printing with subsequent cutting with laser scribe and mechanical cleave method was successful.”

The novel cell design was introduced in the study “Shingling meets perovskite-silicon heterojunction tandem solar cells,” published in Solar Energy Materials and Solar Cells.

Researchers from India's NMIMS Deemed-to-be-University have designed a hybrid renewable energy system based on photovoltaics and tidal energy. They claim the system may cover the entire electricity demand of island resorts.

The scientists proposed to utilize their multi-renewable energy system, which also relies on battery storage, for the Hurawalhi Island Resort, in the Maldives. “The reason to consider the solar-tidal system is that the Maldives has an excellent clearness index and tidal range,” they specified.

Based on their assessment using NREL's HOMER software, the academics analyzed all potential system configurations and then arranged the systems according to the best variable. They assumed the peak load demand of the Hurawalhi Resort to be 451 kW, with the average load demand being 101.01 kW. They also assumed the energy system to generate 2424.25 kWh/day.

Under the proposed system configuration, the PV system had a capacity of 664 kW and a levelized cost of energy (LCOE) of 0.0267$/kWh. The system also relies on a 424 kW converter, a 120 kW tidal turbine and batteries with a combined storage capacity of 2,000 kWh.

“The mean output of a solar energy system is 160 KW and 3839 kWh/day, with a capacity factor of 24.1%,” the research group explained, noting that the hours of operation enabled by the solar energy system is 4380 hrs/year.

Furthermore, the mean output of the tidal turbine is 22.5 KW with a capacity factor of 18.8 % and hydrokinetic penetration of 22.3%. The hours of operation are 8760 hrs/year, with a levelized cost of energy (LCOE) of 0.0314$/kwh.

Through their analysis, the scientists also found that the overall system has a net present cost of $1359,438 and an LCOE of 0.1189$/kwh. “The electricity production through the solar and tidal systems is 1401,086 kWh/day and 197,509 kWh/day, respectively,” they further explained. “This is a totally 100 % renewable energy system, where solar and tidal system contribution is 87.6% and 12.4%, respectively.”

They also validated the cost modeling with chaotic particle swarm optimization and cuckoo optimization techniques, concluding that the analysis shows the reliability and ‘maintainability' of the proposed system. They also warned, however, that the combination of these two technologies requires careful consideration of the local geography, weather patterns, and tidal currents.

“To mitigate this bottleneck, a thorough site assessment should be conducted before designing the system to ensure that the project is economically viable and environmentally sustainable,” they concluded.

The system was introduced in the study “Design, optimization, and data analysis of solar-tidal hybrid renewable energy system for Hurawalhi, Maldives,” published in Cleaner Energy Systems.

Researchers at Japan's National Institute of Advanced Industrial Science and Technology (AIST) have fabricated lightweight, curved crystalline silicon (c-Si) solar modules with a front cover made of polyethylene terephthalate (PET) instead of conventional glass material.

“Our research demonstrates that crystalline silicon solar cell modules with a PET film cover are highly reliable under high-temperature and high-humidity conditions,” the research's corresponding author, Tomihisa Tachibana, told pv magazine. “While we haven't yet calculated the system cost, we anticipate that the weight reduction will likely lower transportation and installation expenses.”

In the paper “Development of lightweight and flexible crystalline silicon solar cell modules with PET film cover for high reliability in high temperature and humidity conditions,” published in Solar Energy Materials and Solar Cells, the Japanese group explained that PET films represent a viable alternative to glass covers, due to their excellent electrical insulation and optical transmittance.

The scientists built the modules with 156 mm² × 156 mm² c-Si polycrystalline aluminum back surface field (Al-BSF) structured solar cells with a thickness of approximately 250 μm. “The strings at the busbar were connected by machine soldering, and the strings of the four-cell modules were connected in series by hand soldering,” they noted.

They used a 0.025 mm-thick PET film for both the module's front cover and the backsheet and encapsulated the panels with ethyl vinyl acetate (EVA). “The module structure was PET/EVA/c-Si cell/EVA/PET or Backsheet,” they added.

The team compared the thermal behavior of the new module with that of a reference panel using a 3.2 mm-thick glass as the front-cover material and found the former exhibited greater flexibility than that fabricated using glass.

It also ascertained, however, that the module based on PET has a 10% lower current value, as the PET film, unlike the glass, has an anti-reflectance structure. The voltage and fill factor values were found to be approximately the same as those of the benchmark glass module. “The absence of a glass cover also imparts the fabricated modules with flexibility, and no cracks or other defects were observed after the modules were placed on and then removed from a measurement stage with a 200 mm radius of curvature,” it further explained.

The scientists emphasized the modules with a PET film cover also have the advantage of reduced weight, approximately “one-fourth per cell size”, which they said makes them ideal for installation in locations with loading restrictions.

They also tested the modules in a series of damp heat (DH) tests at 85 C and under 85% relative humidity and found that the glass-based panel showed degradation in the fill factor and current values after 3000 h because of corrosion of the silver (Ag) front electrodes. “By contrast, the lightweight modules (PET/Backsheet or PET/PET) showed only slightly diminished I–V properties, with about 10% degradation from the initial value after 6000 h of DH testing,” they stated.

The research group believes the PET-packaged modules with their impact-absorbing capacity may accelerate solar deployment in areas such as weight-limited factory roofs and agricultural applications.

Bslbatt, a Chinese storage system manufacturer, has released MacthBox HVS, a residential battery that can operate at an elevated voltage level ranging from 204.8 V to 716.8 V.

“It integrates seamlessly with multiple inverter brands such as Solis, Hypontech, Solplanet, and Deye, enabling homeowners to maximize clean energy and reduce their carbon footprint,” the company said.

The batteries feature individual battery modules with voltage s of 102.4 V. They can be stacked in series with two to seven battery modules.

“MacthBox's modular design simplifies installation and allows for scalability. A single battery module is 5.32 kWh and weighs 50 kg. Homeowners can start with a basic setup and then expand as energy needs grow,” Bslbatt said.

A group of scientists led by Japan's Kyushu University has developed a new technique based on dew-point evaporative cooling (DPEC) to reduce the operating temperatures of photovoltaic panels.

DPEC is a heat and mass transfer technique that has been broadly used for energy conservation in several industrial sectors to date. This technique is one of the most effective and energy-efficient ways to cool down hot air. It has a higher cooling efficiency than traditional evaporative cooling and can reach dew point temperature, which is the temperature point at which the air can hold no more water vapor and is always lower or the same as the air temperature.

DPEC systems are usually designed to supply air into a wet channel as the working air. This enhances the heat and mass transfer process in the wet channel, due to the lower temperature of the incoming working air. “The exhaust air in the DPEC system can reach saturation, while the supply air in the dry channel can reach its dew-point temperature,” the researchers explained. “The proposed system consists of a separate dew-point evaporative cooler that supplies the near-saturation air to the wet air channels which are attached to the back of the PV panels.”

The proposed system consists of two wet channels, one located in the DPEC system itself and another one placed on the back of the PV panel. The DPEC system provides near-saturation cooled air to the wet channel attached at the back of the PV panel where further evaporative cooling occurs to ensure the maximum cooling effect.

The academics claim that the DPEC system is able to considerably reduce the solar panel operating temperature, particularly at the air inlet of the panel. “A large temperature difference between layers at the panel inlet is observed, due to the cool air supplied from the DPEC unit,” they said. “As the air flows along the channel, the temperature difference between each layer is reduced via heat transfer.”

They also explained that the water evaporation process triggered by the continuous heat transfer from the dry channel to the wet channel embedded in the DPEC system and to the wet channel placed in the panel resulted in an increase in air humidity.

The system was tested for 10 h a day, and the group found the DPEC system consumes 0.0736 kg of water, while the second wet channel at the back of the PV panel consumes 0.7157 kg, with total water consumption being about 0.7893 kg.

The team also found that the channel height has a significant impact on system performance. “Increasing the channel height allows a larger amount of unsaturated air to enter the PV panel, which promotes the heat and mass transfer process to control the panel at a lower operating temperature and thus improves the solar cell efficiency,” it stressed.

The researchers compared the performance of a solar module cooled by the novel technique with that of an uncooled panel and of panels cooled by direct evaporative cooling, and DPEC-based sensible cooling systems. They found that, in all cases, the proposed system achieved better cooling performance and maintained higher module efficiency.

“Shorter channel length and larger channel height improve the cooling performance and yield higher efficiency for the PV panel,” they emphasized. “On the other hand, higher inlet air velocity and working air ratio are favorable.”

They presented the system in the study “Dew-point evaporative cooling of PV panels for improved performance,” published in Applied Thermal Engineering.