Two million-kilowatt pumped storage power stations in South China's Guangdong province were placed into full operation on May 28, which has significantly increased the consumption capacity of clean energy in the Guangdong-Hong Kong-Macao Greater Bay Area, and made the region a world-class bay area power grid with the highest proportion of clean energy.

The new Meizhou Pumped Storage Power Station and Yangjiang Pumped Storage Power Station have a total installed capacity of 2.4 million kilowatts, bringing the total installed capacity of pumped storage power grid in the Guangdong-Hong Kong-Macao Greater Bay Area to reach nearly 10 million kilowatts.

The power supply from clean energy generation accounts for nearly 50 percent of the total, and the two stations can support the annual consumption of over 210 billion kilowatt-hours of clean energy.

The pumped storage power station works by pumping water from the reservoir at the foot of the mountain to the reservoir at higher level during the off-peak period at night, and releasing the water to generate electricity in the daytime to meet the demand for power consumption. It is often regarded as the "battery", "voltage regulator" and "regulator" of the power grid.

"The highest demand load of the Guangdong-Hong Kong-Macao Greater Bay Area during the daytime is about 100 million kilowatts, while at off-peak period at night, the demand stands at about 30 million kilowatts, which indicates a great peak-valley difference of power consumption. With the pumped storage hydropower capacity reaching 10 million kilowatts, more clean electricity such as wind power and hydropower can be absorbed at night. Thus a world-class bay area power grid with the highest proportion of clean energy has been built in the Guangdong-Hong Kong-Macao Greater Bay Area," said Li Hua, deputy general manager of the Strategic Planning Department of China Southern Power Grid's Peak and Frequency Regulation Power Generation Co Ltd.

The two new power stations in the Greater Bay Area have also made breakthroughs on many key technologies.

The Yangjiang Pumped Storage Power Station, which has three 400,000-kilowatt generating units, is currently the one with the largest single unit capacity in China. In addition, the height difference between the upper and lower reservoirs of the station reaches 700 meters.

The construction of the Meizhou Pumped Storage Power Station only took 48 months, the shortest for the construction of similar projects.

"We have not only solved many world-class problems in the design of units and the construction of the power stations, but also greatly reduced the project costs. For example, just on the construction of water diversion channels, we saved more than 200 million yuan (about $30 million)," said Wang Chao, mechanical and electrical head of the Yangjiang Pumped Storage Power Station of China Southern Power Grid.

The total investment of the two power stations reached 15 billion yuan, driving the investment of nearly 30 billion yuan in both upstream and downstream industry chains, and improving the design and manufacturing levels of pumped storage equipment in China.