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Company attempts to harness ‘forgotten, renewable energy source’ in the ocean — but major questions remain

Some say the project is a “long shot.”

Some say the project is a “long shot.”

Photo Credit: Global OTEC

A plan based on concepts explored in 1881 to generate electricity using differences in ocean temperatures is getting another shot, nearly 150 years later.

And while the process, called ocean thermal energy conversion (OTEC), has to this point been too expensive to sustain in other attempts over the years, leaders of the venture Global OTEC feel that innovations have advanced enough for another try at the intriguing concept. The effort is geared toward harnessing a “forgotten renewable energy source,” according to a Global OTEC press release. 

“We know Dominique [the new project’s name] is a life-changer for small islands and coastal nations, and that’s why we see the pace of the project on track for success,” Global OTEC founder Dan Grech said in the statement. 

Other ocean-based energy projects harvest wave and wind power at sea. Dominique developers said their concept taps another ready supply of power via ocean heat. 

It works by floating the setup in tropical waters on a barge, named Dominique, in this case, as reported by New Atlas.

The system extracts the heat from sun-warmed sea water near the surface, boiling a refrigerant liquid (like ammonia). This creates a vapor that powers a generator. Cooler water is pumped in from the depths to cool the closed-loop system, per a video clip provided by Global OTEC. 

“That’s how you generate electricity,” the narrator of the clip said, touting clean energy on hand 24/7. 

The clip’s narrator claims that 170 billion barrels of oil would have to be burned to equal the solar energy absorbed by the ocean in tropical regions each day.

In addition to powering nearby islands, the experts feel that “thousands and thousands” of these systems could curb rising ocean temperatures, as well (presumably mostly by avoiding heat-trapping pollution from dirty energy), per the New Atlas report. 

There are, however, major hurdles that the newer tech must prove to have cleared. A Japanese company’s project that went online in 1981, for example, used nearly as much energy to operate as it produced. The sea itself can be an inhospitable place. Tropical storms and corrosive salt water can complicate operations, all according to New Atlas.

The report also includes questions about cost, citing other experts who claim the price of simply proving the concept remains prohibitive. The news outlet concludes that the project is a “long shot.”

Global experts spend much of the nearly three-minute video addressing the storm, operations, and cost concerns. The narrator claims the tech has become smaller, more efficient, and can be mass-produced at scale. And, it’s all safe for the ocean and island environments, the developers report

Dominique is set to begin commissioning in 2025 in waters near São Tomé and Príncipe, an island nation west of Africa. 

What’s more, New Atlas reports that the barge is slated to produce 17% of the nation’s power. If successful, it would be a breakthrough for the energy supply of remote islands. 

“Ocean energy … has the potential to drive the blue and green economy aspirations of small islands and coastal nations,” Martin Lugmayr, an industrial development expert for the United Nations Industrial Development Organization, said in the Global OTEC press release. 

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