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Engineering

How Pumped-Storage Hydroelectricity Evens Out Grid Demand

Quick fact

Pumped-storage hydroelectricity is the most widely used form of grid energy storage, with over 90% of global installed energy storage capacity, and it can respond to demand changes within minutes.

Why this is interesting

You flip on a light switch in the evening, and the lights come on—even though the sun is down and millions of others are doing the same thing. How does the grid instantly meet this surge in demand?