A new hydropower boom uses pumped storage, not giant dams
For a century, hydroelectric power has been synonymous with gigantic dams — feats of engineering that provide renewable energy but displace communities and destroy ecosystems. New research released Tuesday by Global Energy Monitor reveals a transformation underway in hydroelectric projects — using the same gravitational qualities of water, but typically without building large, traditional dams like the Hoover in the American West or Three Gorges in China. Instead, a technology called pumped storage is rapidly expanding. These systems involve two reservoirs: one on top of a hill and another at the bottom. When electricity generated from nearby power plants exceeds demand, it’s used to pump water uphill, essentially filling the upper reservoir as a battery. Later, when electricity demand spikes, water is released to the lower reservoir through a turbine, generating power.