Unlimited long duration, long-lived pumped hydro storage

A new study says the world has far more room for pumped hydro storage than it needs. Pumped hydro works by pumping water uphill to a reservoir when electricity is cheap or plentiful, then letting it flow back down through turbines to generate power when it's needed, like at night or during long stretches of cloudy, windless weather. Researchers identified 800,000 potential sites worldwide, mostly not on rivers, that could together hold enough energy to cover almost three years of global electricity use.

The technology itself isn't new. It's been used for over a century, doesn't require mining, uses less land than an equivalent amount of batteries, and can last up to 150 years, compared to about 15 years for lithium-ion batteries. It's also cheaper per unit of stored energy. Australia's Snowy 2.0 project, for example, is being built for roughly $30-40 per kilowatt-hour of storage. The researchers found that most large countries, including Nigeria and India, have far more suitable sites than they'd realistically need. Bangladesh is a rare exception with limited options.

This isn't something that affects home upgrades or rebates directly, but it matters for the broader shift to solar and wind power. The researchers argue pumped hydro and batteries work best together: batteries handle short bursts of power, while pumped hydro handles the long stretches, storing energy for days or weeks when the sun isn't shining and the wind isn't blowing. That combination is part of what makes a grid running on solar and wind stay reliable.