China ‘could produce 13 per cent more solar power’ if its skies were as clean as in the 1960s
- Effect of pollution that absorbs and scatters sunlight is made clearer by ‘unprecedented’ data, researchers say
- Study underlines the potential rewards as Beijing aims to switch from coal to solar and other clean energy
Researchers from Switzerland, the Netherlands and China studied ground surface solar radiation data from 119 stations across China between 1960 and 2015, and emissions of sulphur dioxide and black carbon – a major component of fine particulate matter PM2.5 – in the same period.
They found the air pollutants, which absorb and scatter sunlight, were an important factor in what scientists refer to as “dimming”.
Based on the country’s solar power generation capacity in 2016, researchers estimated that if solar radiation could return to its 1960s levels, an additional 14 terawatt hours (TWh) of power would be generated.
“We find that reverting back to 1960s radiation levels in China could yield a 12 to 13 per cent increase in electricity generation,” the researchers wrote.
The gains would be even greater by 2030 if China is on track in its planned expansion of solar power production capacity. Researchers estimated that improved sunlight would deliver as much as 74TWh of extra power, or close to 1 per cent of China’s total electricity production by then.
“China is the world’s largest market for solar energy now, and China will play a crucial role in the global shift to clean energy, which we need to prevent catastrophic climate change,” said Stefan Pfenninger, a senior researcher at the department of environmental systems science at ETH Zürich and co-author of the study.
“While air pollution in some parts of the world, like Europe, may be less of an issue today than it was a few decades ago, it is still an urgent issue in many regions, such as China and India,” he said. “So understanding the effect of air pollution on solar power is important.”
The study was published this week in the Nature Energy journal.
China is the world’s largest producer of photovoltaic (PV) power. It had installed 170 gigawatts of solar power capacity by the end of 2018, up from 77GW in 2016, and by 2030 its installed PV capacity is expected to reach 400GW.
Previous studies using about a decade of satellite-derived data had found severe aerosol pollution over China reduced the solar radiation that reached ground level. The new study drew on data from a much longer period, compiled by researchers at China’s National Meteorological Information Centre.
“Having ground-measured data on how much sunlight is reaching the Earth surface across China, going back to the 1960s, was an unprecedented and uniquely powerful source of data to work from,” Pfenninger said.
The study showed that, with growing emissions of sulphur dioxide and black carbon across the country since the 1960s, ground surface solar radiation had been steadily reduced – known as dimming.
In projecting the additional gain in solar electricity what would be possible by returning to 1960s levels of air quality, researchers took into account the differing impacts on both large-scale solar farms in the sparsely populated western China and small distributed solar power production systems in eastern urban China.
China’s solar panel industry faces a year of reckoning
According to New Energy Outlook 2019, released last month by BloombergNEF, a research consultancy, China is expected to have 48 per cent of its electricity generated by solar and wind power by 2050. By then, it is expected to have 1.3TW of solar PV and 1.2TW of wind power installed – 17 per cent of all PV and a third of all wind power installed globally.
“I see the development of solar power as a competition with pollution,” Zhou Lang, a professor at the institute of photovoltaics at Nanchang University, said.
“Pollution affects solar radiation, but the development of photovoltaics will gradually eradicate pollution. We hope photovoltaics will win in the end.”
