Solar power has been eating away at coal’s dominance in generating electricity for quite a while. While coal power is still the largest single source of electricity across the globe, most new generation capacity is coming from solar and wind. However, coal power is fighting back, and not in a good way.
According to new research led by the University of Oxford in England, pollution from coal-fired power plants is significantly reducing the energy output of solar power installations. This is especially true when coal plants and solar installations are located in the same area.
The study examined 140,000 solar photovoltaic installations worldwide using satellite data and atmospheric data on air pollution to calculate how much sunlight is lost due to the dirty air. They found that aerosols – the tiny particles suspended in the air from burning coal – reduced global solar electricity output by 5.8% in 2023. This lost energy adds up to 111 terawatt-hours, the amount generated by 18 medium-sized coal-fired power plants.
The researchers traced the origins of these aerosol-related losses and found coal-fired power generation to be a major contributor. This was particularly evident in China, where solar and coal capacity have expanded in parallel and are often co-located. Air pollution doesn’t just block sunlight. It also changes the nature of clouds, which can cut solar power even further.
As long as we keep burning coal, we may be overestimating how much solar power can contribute to our energy supply.
