"The current energy crisis is fueling a worldwide search for power. Energy explorers are discovering that the largest reserve of potential energy covers more than 70 percent of the Earth's surface—the oceans." Replace "energy crisis" with "climate crisis," and these words could be pulled from the websites of any of several companies that are now looking to generate clean electricity from the heat stored in the oceans.

But to get much juice out of a system like this requires veritable rivers of both warm and cold water. A 100-megawatt OTEC plant (about one-tenth the size of a typical coal-fired power plant) would need several thousand liters of water flowing through it per second.