In January, Chongqing Longwen Industrial, a steel company that uses a large amount of energy, installed a PV system on its factory roof.

"Our rooftop-distributed PV power generation project has already generated more than 160,000 kWh of electricity in less than three months, and the benefits have completely exceeded expectations," said Chen Hao, the company's deputy property manager. "It is expected to save us 600,000 yuan ($82,000) a year."

During public holidays, the power generated by the PV system can be sold to the local power grid to make extra money for the company, he added.

The environmental benefits are more significant. Over 25 years, Longwen's PV project could reduce the use of standard coal by about 5,270 tons, lower carbon dioxide emissions by about 16,000 tons and see dust emissions decline by about 4,370 tons. It could also lower the company's electricity consumption and carbon emissions for more than 35 years.

Shen said Chongqing's PV power generation projects have formed a virtuous cycle with the local environment.

"According to our solar power monitoring system, the number of effective sunshine hours annually has risen from about 600 to 730 in recent years," he said.

"That's because the use of clean energy has improved the air quality and made the skies much clearer."