Solar Energy: China’s Pollution-Hampered Panels Reveal a Big Issue

China, the world’s largest user of photovoltaic solar energy, is not getting the most out of its panels.

The country was home to 130 gigawatts of installed capacity at the end of last year, a figure that’s projected to reach a staggering 400 gigawatts by 2030 and cover 10 percent of the country’s energy needs. But a report published in the journal Nature last month shows those panels have been hampered by black carbon and sulfur dioxide. In short, air pollution from fossil fuels is blocking out sunlight — the very problem the solar panels are designed to solve.

The research, led by ETH Zurich research fellow Bart Sweerts and highlighted by the World Economic Forum on Monday, shows that potential solar output from the 1960s to 2015 fell by somewhere between 11 and 15 percent. The coal-fueled rise of the world’s most populous country hindered the energy source that could prove key to its future growth.

China is not the only country that has to deal with this issue. Not content with acting as a planet-harming predecessor, fossil fuels are actively stopping panels from working to their maximum potential.

Solar Energy: How to Make the Sun Shine Brighter

Solar energy is having a moment in the sun. After years of declining prices, they are now becoming cost-competitive with traditional energy sources. In fact, one report from Energy Innovation in March showed that replacing existing coal plants with wind and solar was now more cost-effective than maintaining the plants in 74 percent of cases. Mike O’Boyle, lead author of the report, told Inverse he wanted to start a “broad conversation.”

A conversation is very much underway about the potential of this energy source. Annual corporate installs have surged in the United States to reach 1.1 terawatt-hours in 2018. In the month of April, renewable energy supplied more electricity than coal in the United States for the first time in industrialized history, and wind and solar are predicted to supply as much as 13 percent of the country’s energy by 2020. Its potential to solve the world’s energy issues has been recognized: one researcher looked at how covering a patch of the Sahara desert in solar panels could provide enough power for the entire world.

According to a 2018 report from the International Energy Agency, globally solar capacity reached 398 gigawatts in 2017. That is set to grow by an extra 580 gigawatts by 2023, accounting for four percent of the world’s energy needs. Renewables as a whole will account for 30 percent of global power demand at that point.

But while solar is soaring, it may not be getting used to its full potential. China, as an example, is currently the world’s biggest polluter. Sweerts’ report notes that, if China returned to 1960s levels of surface radiation from the sun, it could add an extra 12 to 13 percent in electricity generation. That amounts to an extra 14 terawatt-hours by 2016 levels of solar capacity, and possibly an extra 74 terawatt-hours by 2030 capacities.

These impacts may be regional. A report published in PNAS in December 2017 found that aerosol pollution in northern and eastern China, where this pollution is worse, reduced the point-of-array irradiance coming directly from the sun by up to 34 percent. That means a big reduction in the amount of solar radiation reaching the panels themselves.

It’s not just China that’s found this issue. A June 2017 report published in Environmental Science and Technology Letters looked at energy production in China, India, and the Arabian Peninsula. It found that both dust and man-made particulates reduced production by 17 to 25 percent across the regions, amounting to one gigawatt of production lost for India.

Fortunately, there are signs of progress. The New York Times noted in March 2018 that China’s cities had cut fine particulates by 32 percent in just four years. While solar panels may be hampered by this pollution in the air, their adoption could reduce the further release of this matter into the atmosphere.

After Earth’s fourth-hottest year on record last year, it’s a solution that can’t come soon enough.

Read the abstract for Sweerts’ paper below:

China is the largest worldwide consumer of solar photovoltaic (PV) electricity, with 130 GW of installed capacity as of 2017. China’s PV capacity is expected to reach at least 400 GW by 2030, to provide 10% of its primary energy. However, anthropogenic aerosol emissions and changes in cloud cover affect solar radiation in China. Here, we use observational radiation data from 119 stations across China to show that the PV potential decreased on average by 11–15% between 1960 and 2015. The relationship between observed surface radiation and emissions of sulfur dioxide and black carbon suggests that strict air pollution control measures, combined with reduced fossil fuel consumption, would allow surface radiation to increase. We find that reverting back to 1960s radiation levels in China could yield a 12–13% increase in electricity generation, equivalent to an additional 14 TWh produced with 2016 PV capacities, and 51–74 TWh with the expected 2030 capacities. The corresponding economic benefits could amount to US$1.9 billion in 2016 and US$4.6–6.7 billion in 2030.