This startup just tested turning an underwater volcano into a power plant

Last month, a startup called Endurance Energy sailed 300 miles off the coast of Oregon to test something new: deploying geothermal power at an underwater volcano. In a vent field around 5,000 feet underwater, they drilled a two-inch-wide, 52-foot-deep well that tapped into 500-degree heat beneath the ocean floor—the first fully encased well of its kind. Later, as 10-foot waves crashed around their ship, they lowered a three-ton generator to the sea floor to test its ability to create electric...