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Capturing Clean Energy from Tropical Seas

21 November, 2023

Tapping the Red Sea's warm surface waters could deliver a continual flow of renewable electricity, ideal for Saudi Arabia's island communities.

 

Not all sources of renewable energy are intermittent. A continual flow of clean power could be provided by a technology that harnesses the temperature difference between the sea’s surface and deeper waters to generate electricity. The technology could be suited to powering small Red Sea island communities, as calculated by Bassam Dally, a thermo-fluid scientist from KAUST.

Dally came upon the ocean thermal energy conversion (OTEC) concept while exploring alternative potential clean energy sources, he explains. “We were looking at the challenges of storing energy from intermittent renewables such as wind and solar when we realized that we need to broaden our focus,” Dally says. He began to explore energy sources that deliver renewable power more consistently.

 

Bassam Dally, a thermo-fluid scientist from KAUST, investigates the potential of ocean thermal energy conversion (OTEC) technology in the Red Sea as a way to generate electricity in small island communities. ©KAUST 2023; Anastasia Serin


Since joining KAUST in early 2021, Dally has investigated the potential for using OTEC technology in the Red Sea. “Surface water temperatures here can get up to 30 or 35 degrees Celsius during summer,” he says. Just 200 meters below the surface, the temperature falls to around 21 degrees Celsius. “Thermodynamics tells us that, once you have a temperature gradient, you have an energy potential you can do something with,” he says.

OTEC exploits this gradient in a process called an organic Rankine cycle. The hot water is pressurized, then the pressure is immediately released, vaporizing it. The vapor drives a turbine to generate electricity, before being condensed by the cold water to complete the cycle. The power produced is relatively modest; a full-scale unit might power several hundred homes, Dally estimates.

“But you gain continuous clean energy from a device with a small footprint and very little maintenance requirement,” he says.

Read more at KAUST Insight.