Besides pumped-storage hydropower, which accounts for over 90 percent of total global electricity storage, new ways of storing renewable energy are emerging in China.

In pumped-storage hydropower, electricity is used to pump water to the dams, where it is stored as potential energy. When needed, the water is released to drive turbines to produce electricity. The largest facility of its kind is Fengning Power Station in north China's Hebei Province. This year, it proved its ability by helping the Beijing 2022 Winter Olympics run 100 percent on renewable energy.

Catching up are batteries – the most scalable type of grid-scale storage. As the world's top electric vehicle (EV) battery maker, China's Contemporary Amperex Technology Co., Ltd. (CATL) has supplied over 30 percent of global EV batteries. Now, its products have a new place to go, the solar and wind farms, to hook up new energy with the grid. But for now, this method is not cost-effective because lithium-ion batteries have a relatively low energy density.

The good news is that thinner foil is being produced to increase energy density by allowing more electrode material to be packed in the same size battery cell. According to CALT senior manager Liu Yuqing, the thinnest anode that they can produce is 4.5 micron, ranking the top level in the industry.

However, in the eyes of Lu Wengang, the director of China's TELD New Energy, the future of grid storage has already been produced. 

In Lu's opinion, when an EV is taken only as a means of transportation, cruising range of a 50 kilowatt-hour battery is up to 180,000 kilometers during its 10-year use period. It will only consume 30,000 kilowatt-hours of electricity, with 170,000 kilowatt-hours power storage capacity left.

Everyday, after his colleagues drive their EVs to the company, Lu turns on the system which can take over the batteries of their 300 EVs. Cars will instantly become storage for 2 megawatts of solar panels, powering the entire factory. With those EVs and solar panels, his factory will become a micro grid, which is a part of the city grid, participating in a more complex interaction. Energy flows through the cars, and when the shift is over, people drive home in charged EVs. 

By 2040, China could have 300 million EVs, with a combined battery of 20-billion kilowatt hour capacity, equal to the electricity consumed in China for a day.

All the above-mentioned new ways of storing renewable energy are changing the way humans use energy. With huge potential, maybe someday they could drive the new energy revolution.

To know more stories about carbon neutrality, check out the rest of CGTN's documentary Human Carbon Footprint.