A new study has found that pollution from coal-fired power plants is significantly reducing the energy output of solar photovoltaic installations.

  • Pollution from coal-fired power plants that blocks sunlight is significantly cutting global solar output, and potentially causing an overestimation of climate progress.

  • Aerosols – tiny particles released from the burning of fossil fuels as well as natural sources like volcanoes – reduced global solar generation by 5.8 per cent in 2023, according to the study.

  • In China, the world’s largest producer of solar power and coal, aerosols slashed photovoltaic output by 7.7 per cent, with scientists attributing nearly a third of the decline to coal-fired power plants. Aerosols also cut solar output in India, the US and Japan.

  • “Given the slow pace of global coal phase-out, these results reveal a constraint on solar performance that, if unaccounted for, could lead to a systematic overestimation of the transition’s contribution to climate and air quality goals,” the study concludes.

Here is the study: Coal plants persist as a large barrier to the global solar energy transition (pdf)

Archived version

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Between 2017 and 2023, new PV installations added an average of 246.6 TWh of electricity each year, while aerosol-related losses from existing systems reached 74.0 TWh annually - equivalent to nearly one-third of the gains from new capacity. This highlights a previously unrecognised interaction between fossil fuel use and renewable energy, where emissions from one system directly reduce the performance of the other.

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This effect is particularly evident in China, where solar and coal capacity have expanded in parallel and are often co-located. Regions with high coal capacity aligned closely with areas experiencing the greatest solar PV losses.

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China is the world’s largest solar producer, and generated 793.5 TWh of solar PV electricity in 2023 (41.5% of the global total). But it also experienced the largest losses from aerosols, with total output reduced by 7.7%. The researchers estimate that around 29% of aerosol-related solar PV losses in China come specifically from coal-fired power plants. Coal plants emit fine pollution particles that scatter and absorb sunlight, reducing the amount that reaches nearby solar panels. As a result, the panels generate less electricity than they otherwise could.

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