BEIJING, June 12 -- Construction began on new hydropower plants with advanced electricity storage in central and east China on Friday, marking the country's latest effort to promote clean energy.

State Grid Co., the world's largest electric utility company, began building the three power stations, which can store hydropower to be used during periods of high-demand, in Anhui, Shandong and Henan provinces.

With a capacity of 3.6 million kilowatts and total investment of21.7 billion yuan (3.55 billion U.S. dollars), all the projects are scheduled to be completed and put into operation by 2021, the company said.

The power plants are expected to reduce China's greenhouse gas emissions, cutting carbon dioxide by 3.64 million tonnes as well as sulfur dioxide and other fumes, equivalent to consumption of 2.18 million tonnes of coal.

The company currently has 19 hydropower plants with another 12 planned or under construction in the country's central and eastern areas. Total capacity is expected to reach 38 million kilowatts by2020.

The projects will be a push for the national ambition to increase the share of non-fossil fuels in its power grid and gradually replace prevailing but heavily-polluting thermal power generated from coal.

China has been working to promote hydropower, wind power, solar power and nuclear power. Its installed hydropower capacity surpassed 300 million kilowatts by the end of 2014, making up around a quarter of the world's total.

The power stations will also help improve China's ultra-high voltage grid, improving its safety and reliability, said Zhang Zhengling, spokesperson of the electricity giant.