HI-Powered: Hawaii's Cutting-Edge Experimental Power Plant

Charles Williams

An experimental method that depends on ocean temperatures can generate electricity to power up to 120 homes.

Parched atop the 50-foot platform overlooking the coastline at Keahole Point, on Hawaii's Big Island, engineer Michael Eldred points to where the whales and dolphins frequently come to feed. Below, waves crash against black volcanic rock, sending spray into the warm afternoon air. Not a bad place to work. 

The platform caps an experimental power plant that provides a window into tomorrow’s alternative energy production. It’s a plant for ocean thermal energy conversion (OTEC), an electricity-generation method that takes advantage of the temperature difference between cold water from the deep and warm surface waters. 

Contrast that to solar and wind power; passing clouds or a diminished breeze can dramatically alter output. “OTEC is exempt from that problem,” says Eldred, who wears a hard hat and flip-flops. “It’s inherently stable because you can control and maintain how much electricity it produces simply by controlling the amount of water.” Elegant, yes, but factors such as geographic limitations, efficiency, and construction challenges make deploying these kinds of systems anything but a sure bet.

Nevertheless, this plant, built by a company called Makai Ocean Engineering with support from the state of Hawaii and the U.S. Navy, is a crucial proof of concept—it can even power up to 120 homes. This is especially important in a place where electricity prices are so ridiculously high. State officials have set the ambitious target of having Hawaii rely 100 percent on renewable power by 2045, with a push for alternative energy development as well as efficiency initiatives that would cut consumption by some 30 percent. (Lanai, the island owned by billionaire Larry Ellison, aims to be the first of the Hawaiian Islands to end its fossil-fuel dependency.) 

Don’t expect to see massive OTEC plants anchored in harbors near you anytime soon. But in the decades ahead, as societies come to realize that humanity’s portfolio of renewables needs diversification, OTEC could become part of our suite of solutions. As Eldred puts it: “It’s no longer science fiction to develop a next-generation renewable energy source.”