Solar energy is one of the widely advocated renewable energy sources. Many countries that are aiming to cut down carbon emission choose solar energy particularly regions with ample daylight. Also, it is easy to light remote areas using solar power compared to other alternative energy sources.

Inasmuch as solar energy sounds promising in cutting down the burning of fossil for energy, a new study has shown that airborne particles can reduce energy output of solar cells by an alarming twenty-five percent in some parts of the world. The EU has set air pollution limits but some countries in the bloc are falling short of that limit.

Regions with dense smog will experience the most reduced solar cells efficiency. This includes countries like India, China, some countries in Eastern Europe, and the Arabian Peninsula. The study which was carried out by a Duke University professor of civil and environmental engineering, Michael Bergin appeared online in the Environmental Science & Technology Letters on June 23.

How Air Pollution Can Affect Solar Energy Output?

When air is polluted, it contains dust and other pollutants that can cause haze which shields the sun’s rays, in other words, act as a light filter. This haze effect produced by pollutants limits the amount of sunlight that gets to the solar cells. The effect is that the solar cells are unable to harness the full sunlight to produce energy.

solar energy output
The haze effect produced by pollutants limits the amount of sunlight that gets to the solar cells.

A group of Chinese scientists working to provide ten percent of total electricity demand using solar photovoltaic (PV) cells also discovered that some of the aerosol pollutants have the ability to scatter or absorb sunlight reducing by a significant amount the solar radiation that would have been used for photovoltaic electricity generation, a phenomenon known as the screening effect.

Also, these airborne pollutants and dust are usually transient an usually settle on any surface they come in contact with. When they land on the surface of the solar panels, they also limit the amount of light that passes through the solar cells. It is true that a strong air current can cause dust to become airborne but the majority of the pollutants in the air usually result from human activities including exhaust fumes from cars, burning of coal to produce electricity, the operation of various factories, and so on.

What Prompted The Research?

Professor Bergin was delighted to watch his colleagues show off some of the solar installations they had on rooftops. However, he was also amazed by how dirty they were. Logically, such amount of dirt on a solar cell surface will definitely cut down its efficiency. However, there was no report on a study to determine or estimate the losses so Bergin put together a model that would help him to measure the losses.

In collaboration with colleagues from the University of Wisconsin, and India Institute of Technology-Gandhinagar, Bergin was able to measure the reduction in the solar energy efficiency of the IITGN solar panels as they become dirtier when left over several weeks. The team of researchers also discovered that each time the surface of the solar panels were cleaned, the energy efficiency jumped by fifty percent.

The researchers went a step further to analyze the grime collected from the surface of the solar panels to know their composition. The result showed that ninety-two percent were dust while the remaining eight percent was a heterogeneous composition of ion pollutants from human activities and carbon.

Even though carbon and ion pollutants were eight percent which seems small compared to the ninety-two percent dust, the researchers noted that light is more effectively blocked by smaller human activities borne particles than by dust. Bergin also noted that the human-made particles are more difficult to get off the surface because they are sticky. Regular cleaning of the solar panels will seem like the best solution but the more you clean the solar panels the higher their risk of getting damaged.

The Cause Of Solar Power Loss Varies

In as much as Bergin proposed that a small human-made particle can cause more harm than dust, in some areas like the Arabian Peninsula, clouds of dust appear to be the major limiter of solar efficiency. A large construction zone can cause a rapid buildup of pollutants which may cause loss of efficiency beyond the estimated twenty-five percent.

solar power loss
There are varied causes of solar power loss

The Negative Impact Of The Loss Of Solar Efficiency On The Economy

Air pollution tends to nullify the billions of dollars spent on renewable energy – solar power in this case. In India, for example, this causes power generation to plunge by about 3,900 megawatts. This amount of lost energy is about 6 times what the largest solar farm in the country generates. As India is set to increase its solar ambition, so will the losses rise. This loss is highly significant considering the fact that India is planning to use solar energy to power hundreds of homes of the poorest citizens.

China is the most solar energy generator in the world but pollution in the country is also one of the largest in the world, particularly from the burning of fossil fuels. The result is that China is likely to be losing as much as 11 gigawatts of solar energy, the researchers estimated. This is the energy needed to power 1.1 billion LED bulbs. This lost energy is also equal to the production capacity of one thousand one hundred coal-fired power plant or five thousand five hundred large-scale wind turbines.

The energy lost to pollution is also equivalent to what 50.6 million PV solar panels working at full power would generate. To make up for the loss, China will need to spend $10 billion equivalent annually.

The effect of air pollution on health is well-known but the effect on energy is dizzying too. This project was supported by the Office of the Vice Provost for Research at Duke University and the US Agency for International Development. It further elucidates the importance of policymakers around the world to work hard to cut down emissions. Obviously, pollution has both health and economic reasons. Cleaning the skies can simultaneously solve both problems.