A staff member walks past the solar panels at a sewage treatment plant in Shishi City, southeast China's Fujian Province, Nov. 20, 2018. The photovoltaic power station built over a sewage treatment plant got connected to the grid and started power generation. Covering an area of more than 4,000 square meters, the photovoltaic power station is expected to generate 3.5 million kilowatt-hours per year. (Xinhua/Song Weiwei)

Solar panels are seen at a sewage treatment plant in Shishi City, southeast China's Fujian Province, Nov. 20, 2018. The photovoltaic power station built over a sewage treatment plant got connected to the grid and started power generation. Covering an area of more than 4,000 square meters, the photovoltaic power station is expected to generate 3.5 million kilowatt-hours per year. (Xinhua/Song Weiwei)

Photo taken on Nov. 20, 2018 shows the sewage treatment plant in Shishi City, southeast China's Fujian Province. The photovoltaic power station built over a sewage treatment plant got connected to the grid and started power generation. Covering an area of more than 4,000 square meters, the photovoltaic power station is expected to generate 3.5 million kilowatt-hours per year. (Xinhua/Song Weiwei)

A staff member walks past the solar panels at a sewage treatment plant in Shishi City, southeast China's Fujian Province, Nov. 20, 2018. The photovoltaic power station built over a sewage treatment plant got connected to the grid and started power generation. Covering an area of more than 4,000 square meters, the photovoltaic power station is expected to generate 3.5 million kilowatt-hours per year. (Xinhua/Song Weiwei)

Solar panels are seen at a sewage treatment plant in Shishi City, southeast China's Fujian Province, Nov. 20, 2018. The photovoltaic power station built over a sewage treatment plant got connected to the grid and started power generation. Covering an area of more than 4,000 square meters, the photovoltaic power station is expected to generate 3.5 million kilowatt-hours per year. (Xinhua/Song Weiwei)

Solar panels are seen at a sewage treatment plant in Shishi City, southeast China's Fujian Province, Nov. 20, 2018. The photovoltaic power station built over a sewage treatment plant got connected to the grid and started power generation. Covering an area of more than 4,000 square meters, the photovoltaic power station is expected to generate 3.5 million kilowatt-hours per year. (Xinhua/Song Weiwei)

Solar panels are seen at a sewage treatment plant in Shishi City, southeast China's Fujian Province, Nov. 20, 2018. The photovoltaic power station built over a sewage treatment plant got connected to the grid and started power generation. Covering an area of more than 4,000 square meters, the photovoltaic power station is expected to generate 3.5 million kilowatt-hours per year. (Xinhua/Song Weiwei)

A staff member walks past the solar panels at a sewage treatment plant in Shishi City, southeast China's Fujian Province, Nov. 20, 2018. The photovoltaic power station built over a sewage treatment plant got connected to the grid and started power generation. Covering an area of more than 4,000 square meters, the photovoltaic power station is expected to generate 3.5 million kilowatt-hours per year. (Xinhua/Song Weiwei)