Coal‑Derived Aerosols Cut Solar Output by Over 500 TWh Each Year

Solar capacity has risen rapidly worldwide, adding an average of 250 terawatt‑hours of potential generation each year from 2018 to 2022. This growth reflects falling costs and strong policy support for renewable energy. Yet airborne particles scatter sunlight before it reaches panels, cutting the actual output. These particles, known as aerosols, arise from both natural sources like sea spray and human activities such as fossil‑fuel burning. Researchers built a global solar‑fleet inventory by combining known facility lists, AI‑analyzed satellite imagery, and crowdsourced location data, then used local weather records to estimate clear‑sky production and compare it to real‑world output. The approach allowed them to isolate the impact of clouds and aerosols from other variables like temperature or equipment degradation.

In 2023, more than a quarter of potential solar power was lost, with six percent of that loss tied to aerosols, amounting to over 500 terawatt‑hours—equivalent to the annual generation of 84 one‑gigawatt coal plants. Clouds accounted for the remaining portion of the loss, highlighting that aerosols are a distinct and measurable factor. Over the five‑year span 2018‑2022, the yearly increase in solar potential averaged 250 terawatt‑hours, but aerosols prevented 75 terawatt‑hours of that gain each year. This means that roughly three out of every ten terawatt‑hours of new solar potential were nullified by aerosol interference annually. The study notes that both natural and human‑made aerosols, many originating from coal combustion, reduce solar panel output by hundreds of terawatt‑hours annually. The researchers emphasized that reducing emissions from coal plants could directly improve solar harvests.

These losses represent a significant drag on the climate benefits of expanding solar, effectively offsetting part of the clean‑energy gains meant to replace fossil fuels. In practical terms, the aerosol‑related shortfall is comparable to removing dozens of gigawatts of solar capacity from the grid. As solar continues to grow, monitoring aerosol concentrations and their sources will become essential for accurate generation forecasts and grid planning. Improved aerosol tracking could help operators anticipate shortfalls and adjust storage or dispatch strategies accordingly. Future research will need to quantify how changes in emissions policies affect aerosol levels and, consequently, solar yield. Such insights will inform cost‑benefit analyses of air‑quality regulations alongside renewable‑energy targets.