Global solar power generation hit an all-time high this month, with new capacity additions in Q1 2026 up 27% year-on-year, according to the International Energy Agency, IEA. But the surge comes as operators and grid managers raise concerns that dangerously high ambient temperatures are cutting output and stressing infrastructure.
Record Growth Driven by Cost and Policy
Utility-scale solar projects in China, the United States, India, and the Middle East pushed global installed capacity past 2.1 terawatts in April. Falling module prices and streamlined permitting under 2024’s Clean Grid Acceleration Act in the US and similar frameworks in the EU have accelerated deployment.
“Solar is now the cheapest new-build electricity source in 95% of markets,” said Laura Méndez, IEA renewables lead. “We’re seeing rooftops and deserts both contributing to a record spring.”
The Heat Problem
While more sun usually means more power, solar photovoltaic, PV, panels become less efficient as temperatures rise. Most commercial panels lose 0.3% to 0.5% of output for every degree Celsius above 25°C. During recent heatwaves in Texas, southern Spain, and Rajasthan, site-level data showed daytime generation 12–18% below rated capacity despite clear skies.
“The term ‘dangerously high’ isn’t about safety,” said Dr. Emeka Odu, grid engineer with the West African Power Pool. “It’s about system risk. When it’s 45°C and demand for cooling spikes, solar output is sagging right when we need it most.”
Heat also accelerates degradation. A 2025 study by the National Renewable Energy Laboratory found that modules in persistently hot climates could lose 1.2% of performance per year, versus 0.5% in temperate zones, shortening financial lifetimes.
Grid and Safety Pressures
Operators report two additional heat-related strains:
Inverter derating: High ambient temperatures force inverters to throttle output to avoid overheating, cutting plant production further.
Fire risk: Wildfire conditions near solar farms in California and Portugal prompted precautionary shutdowns last week, despite no panel fires recorded.
Industry Response
Manufacturers are shifting to heat-resilient technologies. Bifacial modules with better ventilation, heterojunction cells with lower temperature coefficients, and tracker systems that stow at high noon are gaining market share. Project developers in the Gulf are now spacing rows wider and raising mounting heights to improve airflow.
Battery storage is being paired with solar to cover late-afternoon gaps when heat is high but panel efficiency drops. “Solar + 4-hour storage is becoming the default in hot markets,” said Méndez. “You generate when you can, dispatch when you must.”
Policy Outlook
Regulators are updating performance models to account for climate-driven heat. The UK’s National Grid ESO will include temperature derating in its 2027 capacity market auctions. In Nigeria, the Rural Electrification Agency is piloting white reflective membranes under arrays to cut ground heat by 4°C.
“We need solar to soar, but we also need it to be heat-smart,” Dr. Odu said. “The energy transition won’t work if our best asset underperforms every summer.”
