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Ocean Thermal Energy: Back From the Deep

Makai Ocean Engineering preps a 100-kilowatt test facility on the Hawaiian coast, while others look offshore

3 min read
Ocean Thermal Energy: Back From the Deep
Tower of Power: A system in Hawaii generates electricity by exploiting the temperature difference between the ocean’s cold depths and warm surface.
Photo: Rachel Courtland

This month, the Hawaii-based firm Makai Ocean Engineering will prepare to hoist a small turbine up a spare steel structure with a commanding view of the Pacific Ocean. There, with a flood of near-freezing water piped up from 1,000 meters below the surface, the company will put what will be the largest experimental ocean thermal energy plant through its paces.

Ocean thermal energy conversion, or OTEC, is an approach to energy generation that harnesses the temperature difference between surface and deep-sea waters. It’s an energy dream that made inroads in the late 1970s and early 1980s, only to fizzle once oil prices fell. But there are some suggestions that it is again gaining momentum.

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This photograph shows a car with the words “We Drive Solar” on the door, connected to a charging station. A windmill can be seen in the background.

The Dutch city of Utrecht is embracing vehicle-to-grid technology, an example of which is shown here—an EV connected to a bidirectional charger. The historic Rijn en Zon windmill provides a fitting background for this scene.

We Drive Solar

Hundreds of charging stations for electric vehicles dot Utrecht’s urban landscape in the Netherlands like little electric mushrooms. Unlike those you may have grown accustomed to seeing, many of these stations don’t just charge electric cars—they can also send power from vehicle batteries to the local utility grid for use by homes and businesses.

Debates over the feasibility and value of such vehicle-to-grid technology go back decades. Those arguments are not yet settled. But big automakers like Volkswagen, Nissan, and Hyundai have moved to produce the kinds of cars that can use such bidirectional chargers—alongside similar vehicle-to-home technology, whereby your car can power your house, say, during a blackout, as promoted by Ford with its new F-150 Lightning. Given the rapid uptake of electric vehicles, many people are thinking hard about how to make the best use of all that rolling battery power.

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