Global-warming-induced degradation could raise rooftop solar LCOE by up to 20%

A global study finds climate change will sharply increase high-temperature risks, accelerate degradation, and raise costs for rooftop PV, with economically disadvantaged regions hit hardest. Researchers warn current IEC standards underestimate future risks, urging urgent updates to avoid stranded assets and rising electricity costs.

February 19, 2026 Lior Kahana

Image: pv magazine

A study by an international team of researchers finds that climate change is set to increase the risks of high temperatures, accelerated degradation, and higher costs for rooftop solar globally.

By combining climate models with solar degradation and economic simulations, the researchers projected which regions of the world’s rooftop solar would be most affected, and pinpointed where modules are likely to suffer the most from rising temperatures.

“This is the first global analysis quantifying how climate change will affect high-temperature risks for rooftop solar panels, which are particularly vulnerable to degradation because constrained mounting gaps trap heat,” said leading author Haochi Wu to pv magazine.

“Previous studies examined efficiency losses from warming or changes in solar irradiance—factors that cause modest, often uncertain impacts. We addressed a blind spot: accelerated degradation from sustained high operational temperatures, which no one had systematically modeled at a global scale under future climate scenarios.”

Wu highlighted that his findings show the solar industry “urgently” needs to adapt its high-temperature risk standards for a warmer future.

“The current international standard IEC-63126 defines where high-temperature risk occurs based on historical weather data—roughly the 1998–2020 period,” he said.

“Our analysis shows this standard accounts for only 74% of global capacity at risk under 2 C warming and just 48% under 4 C warming. If standards aren’t updated to reflect future climate projections, both investors and installers will underestimate degradation risk, leading to stranded assets and unexpected replacement costs.”

To make their projections, the team used a chain of models with several components. The first incorporated future climate data from 20 CMIP6 models, a state-of-the-art collection of climate simulations projecting conditions through 2100, which were further bias-corrected.

Following the growing consensus on quantifying climate impacts, they assessed effects at 1–4 C of warming, in 0.5 C intervals, relative to the preindustrial period.

Next, solar operational models calculated how hot rooftop systems would get. Using climate-model inputs—including projected solar irradiance, air temperature, and wind speed—they estimated module temperatures and hourly energy generation worldwide.

All simulations assumed crystalline silicon (c-Si) modules on 20°-tilted roofs facing the equator (azimuth 180° or 0°). According to International Electrotechnical Commission (IEC) standards, a standard high-temperature risk (HTR) occurs when the 98th percentile of module temperatures exceeds 70 C, while an extreme HTR occurs above 80 C.

Finally, the team applied the Arrhenius physical-chemical model to simulate module aging based on temperature. Assuming a baseline degradation of 0.66% per year and defining a module as unusable after 20% power loss, they calculated the levelised cost of electricity (LCOE) for modules experiencing higher temperatures, shorter lifetimes, and reduced annual output.

“The magnitude of the LCOE increase really stood out. At 2.5 C warming, some regions see levelised cost increases up to 20%—roughly three times larger than impacts from efficiency or irradiance changes that prior research focused on,” Wu said.

“The inequity of this raise also stood out. Economically disadvantaged areas—Africa, South Asia, parts of South America—face substantially greater cost increases than wealthier regions. At 4 C, warming doubles the LCOE burden in the most vulnerable regions compared to less vulnerable ones.”

“The solar industry often frames distributed PV as a tool for energy equity, but our results show that without adaptation, climate change could undermine that promise. Climate change doesn’t just increase degradation globally; it widens the gap between regions.”

The team also found that at 4 C of warming, global rooftop PV capacity exposed to high-temperature risk nearly doubles compared with historical levels.

“We provide updated global reference maps that could inform standard revisions,” he concluded.

“We’ve been in contact with experts from IEC Technical Committee 82—the body responsible for solar photovoltaic energy system standards—during our research. They expressed a strong interest in our work mapping high-temperature risk under future climate scenarios. We are looking forward to deeper collaboration with the committee to help translate these findings into updated guidelines.”

The research findings were presented in “Climate change will increase high-temperature risks, degradation, and costs of rooftop photovoltaics globally,” published in Joule. Scientists from China’s Peking University and Zhejiang University, as well as from the University of Michigan and Purdue University in the United States, have contributed to the research.

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