World's largest hybrid pumped-storage power project hits key milestone

On the Western Sichuan Plateau at an altitude of 3,000 meters, the world's largest hybrid pumped-storage power station under construction – the Lianghekou hybrid pumped storage project – reached two major construction milestones on Sunday. Excavation of the underground powerhouse was completed while concrete pouring began for the downstream reservoir.

It uses the Lianghekou Reservoir, Sichuan's largest super reservoir, as the upper reservoir and the Yagen Level-1 Hydropower Station reservoir as the lower reservoir.

The plant is equipped with four reversible units of 300 megawatts each. Operating jointly with the 3,000-MW conventional units of the Lianghekou project, the total installed capacity will reach 4.2 gigawatts. Once completed, the facility will provide both natural runoff power generation and bidirectional regulation through pumped storage.

The underground powerhouse, described as the project's "power heart," is the core hub of the entire development. Buried approximately 500 meters beneath the mountain, it stretches nearly 200 meters in length, stands 60 meters high, and reaches a maximum burial depth of 650 meters.

This high-altitude green-energy "super power bank" is rapidly taking shape and is expected to play a vital role in strengthening clean-energy supply security and enhancing grid regulation capabilities in China.