4 New Ways to Store Renewable Energy With Water

Stash it away in concrete bunkers, undersea bags, and other strange places

4 min read
Photo: DNV GL
Earth, Wind & Water: DNV GL’s energy island concept creates a lake in the ocean that stores wind energy by pumping water out.
Photo: DNV GL

If Elon Musk has his way, in the future we’ll all be storing renewableelectricity inside big banks of lithium-ion batteries. But let’s not forget the energy storage situation today. In the United States, 97 percent of utility-scale storage in 2014 was in pumped-storage hydroelectric plants, according to research by Oak Ridge National Laboratory, in Tennessee.

In traditional pumped hydro, a dam separates a lower reservoir from an upper reservoir. When a utility company needs to store energy, the system pumps water from the bottom to the top. It generates electricity when water flows back down through a turbine. In 2015, Citibank estimated that the cost of power from pumped hydroelectric was about 5 percent of the cost of grid-scale battery-stored electricity. The problem is that there are many places that “consume high amounts of power but don’t have geological opportunities to build conventional pumped-storage plants,” says Jochen Bard, an energy processing technology manager at the Fraunhofer Institute for Wind Energy and Energy System Technology (IWES), in Germany.

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An illustration of pipes going around from hot to cold behind a chinese animal statue on a pedestal.
MCKIBILLO

Jutting out from the coast of China’s Fujian province, Changbiao Island may seem small and unremarkable. It is anything but. This is where the China National Nuclear Corp. is building two fast-neutron nuclear breeder reactors, the first of which is slated to connect to the grid in 2023, the second in 2026. So China could start producing weapons-grade plutonium there very soon.

They are called breeder reactors because they produce more nuclear fuel than they consume. According to Chinese authorities, the ones on Changbiao are civilian power reactors, designed to generate 600 megawatts of electricity each, which amounts to a little more than 1 percent of the total capacity of China’s nuclear power sector. But each reactor could also yield up to 200 kilograms of weapons-grade plutonium each year, enough for about 50 nuclear warheads—which is making nuclear-arms-control experts in Western countries nervous.

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