Air pollution in India reducing solar power yield by 17-25 percent
India has taken a vast step towards the use of renewable products and the solar power facility is expected to double this year. It is a big push for solar energy but the level of air pollution might impact the efforts in some part of the country.
The target is to set solar capacity of 100 giga watts by 2022 under the Jawaharlal Nehru National Solar Mission. Even if the goal is reached, some of the solar panels may not generate electricity with full potential without regular cleaning.
According to a new study, it has been found that particulate matter (PM) and dust may be reason due to which the power of solar panels in North India is decreasing by 17-25% annually. The study showed that half of the reduction is caused by dust and the particles that were deposited on the surface of solar panels formed a physical barrier for the entry of light. The decline in energy yield is due to ambient pollution which reduces the amount of sunlight reaching the ground. This phenomenon is known as solar dimming.
Professor Mike Bergin, who led the study, said that cleaning the panels is not enough. An improvement in the quality of air can lead to the enhancement in solar energy yield. The solar power plants are dependent on the availability of sunlight and the obstructions between sunlight and photovoltaic panels reduce potential energy generation.
In 2016, a study from Baghdad found 18.74% decline in efficiency of solar modules which were not cleaned for a month. Another study from Colorado, USA in 2014 showed that 4.1% of light transmission was lost for every gm2 of dust gathered on the photovoltaic plate.
The losses caused due to air pollution have received very less attention. In 2013, researchers investigated the output of 10 photovoltaic systems during a smog episode in Indonesia. The study showed that the system output declined by around 25% due to lower air quality. The head of operations at the Cleantech Solar in Singapore said that the output was reduced by 50% on one particular day. He also observed that there would be an additional consequence of soiling on the panels for a city like New Delhi as the place is much drier and dirtier.
The study of Bergin is one of the first that quantifies the combined force of deposited matter and ambient particles. He analysed the deposits on solar panels along with his colleagues in IIT, Gandhinagar. They tracked the energy yield of solar panels before and after cleaning. They developed a model on the basis of approximate change in solar panel transmission per unit mass deposited.
The proportions of pollution and dust in the parts of North India were found to be nearly equal. The study showed that power generation increased by 50% after each cleaning. Frequent cleaning is one part of the solution for the pollution problem.
According to Nobre, Air pollution is now an aspect in business decisions. His company has several solar projects across Asia including that of India. He said that developers will be more careful while signing power purchase contracts which have facilities sited in highly polluted areas. The task force of PV systems is radically growing in India and this could lead to a loss of millions of dollars in revenue. The pollution in air not only harms public health and the environment, it also undermines the productivity of the clean energy.