India’s push for solar energy which is reported to double this year could be offset by air pollution. In a new study, it has been found that dust and particulate matter (PM) could be attributed to reducing the energy yield of solar power systems in the north of India to around 17% to 25% annually.
According to Duke University professor, Mike Bergin, who led the study said that nearly half of the reduction came from dust and particles which were deposited on the surface of solar panels and formed a physical barrier to the light entry. The reduction came from ambient haze from air pollution, which is a condition better known as solar dimming. Bergin said that the study showed that improving air quality could lead to a big improvement in solar energy yield. He added that cleaning panels would not be enough.
Dust can affect the solar panel output significantly, and this was reiterated in a 2016 study in Baghdad, which found around 18.74% decline in efficiency of solar modules which were left uncleaned for around a month.
Losses from air pollution have received less attention. In a 2013 study, researchers investigated the power output of around ten PV systems in Singapore during a haze episode. The study reported that the system output declined due to lower air quality by around 25% over a 10-week-period. According to Andre Nobre, lead author and head of operations at the Cleantech Solar in Singapore, the output on a particular day reduced to a staggering 50%. He observed that for a city like New Delhi, there would be an added effect of soiling on the panels due to the fact that the city is much drier and dirtier.
The Bergin study is one of the first which quantifies the combined impact of ambient particles and the deposited matter. Bergin and his colleagues have analysed deposits on the solar panels at the IIT, Gandhinagar campus and have tracked energy yield pre-and-post cleaning. The study found that power generation increased by around 50% after each cleaning.
Nobre said that air pollution was a factor in solar power plant business decisions, for those companies having solar project across Asia including that of India. He added that developers would be cautious when signing power purchase agreements with clients who had facilities in highly polluted zones.