Sébastien Moret—Nant de Drance
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After 14 years of construction—including excavation of 10.5 miles of subterranean tunnels—a giant water battery began operating in July in the heart of Europe. Wedged high in the Swiss Alps, the Nant de Drance pumped storage power plant aims to help stabilize Europe’s power supply while supporting the transition to renewable energy. Excess power, including from solar and wind, can be “stored” in the plant’s two reservoirs; water moves between them down a steel pipe taller than the Eiffel Tower to power six turbines about 2,000 ft (600 m) underground. The $2 billion system, the largest of its kind in Europe, can store up to 20 million kilowatt hours—similar to the capacity of 400,000 car batteries.

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