In 2020, a three-turbine frame was lowered into New York City's East River; six months later, it had sent 210MWh of tide-made power to the U.S. grid

In October 2020, workers lowered a strange metal frame into New York City's East River. It held three underwater turbines, each shaped a bit like a boat propeller. Six months later, the turbines had produced 210 megawatt-hours of electricity. According to the U.S. Department of Energy, this was a new U.S. record for production of marine energy. It also showed something bigger: the ocean’s tides can quietly help power a modern city.

How three turbines turned water into power