Air quality impacts on rooftop photovoltaic energy production during the 2019–2020 Australian bushfires season

The ”Black Summer” 2019–2020 bushfires covered large areas of eastern Australia, causing substantial health impacts, animal deaths and damage to infrastructure. The smoke-related aerosols produced from these fires can also impact solar energy production by attenuating useable radiation. This study assesses the impacts of high particulate matter (PM) concentrations in photovoltaic (PV) energy production in New South Wales (NSW), from November 2019 to January 2020, during the bushfire season. We use in-situ measurements of commercial rooftop PV systems, pollution data from NSW Air Quality Monitoring Network and the Schools Weather and Air Quality, and satellite information from Himawari-8. We focus the study on clear days to eliminate the effects of clouds and concentrate on the impact of PM alone. We compare the energy generated by rooftop PV systems during clean/polluted conditions with a statistical conditional analysis approach. Results show that most locations exhibit similar behaviour, with PV generation reductions in polluted environments compared to clean conditions. The air quality impacts are stronger in locations near bushfire burning areas. For instance, in Katoomba, mean reductions up to 20% in the generated PV energy are found during high PM episodes. High-speed westerly winds transported the smoke several hundreds of kilometres, influencing the air quality and PV energy generation in most stations across Sydney. On a particular day of high bushfire activity (10 December 2019), we use satellite information to show how smoke caused increases in aerosol levels, increased PM concentrations, attenuated radiation and produced up to 65% reductions in hourly PV energy.