The concept was first invented in 1881, but it’s taken until August of 2015 for a viable commercial Ocean Thermal Energy Conversion (OTEC) plant to be built. There’s a great article we found over on the Popular Science website on the new plant that is coming online in Hawaii that takes advantage of the temperature difference between the ocean’s surface and its depths.
According to the article, this is how OTEC works:
Inside the system is a liquid that has a very low boiling point (meaning that it requires less energy to evaporate), like ammonia. As ammonia passes through the closed system of pipes, it goes through a section of pipes that have been warmed by seawater taken from the warm (77 degrees Fahrenheit), shallow waters. The ammonia vaporizes into a gas, which pushes a turbine, and generates power. Then, that ammonia gas passes through a section of pipes that are cooled by frigid (41 degrees Fahrenheit) seawater pumped up from depths of around 3,000 feet. The gas condenses in the cold temperatures, turning back into a liquid, and repeats the process all over again. The warm and cold waters are combined, and pumped back into the ocean.
Factiod: Did you know that almost every form of electrical energy generation – even nuclear plants – essentially boil a liquid, usually water, to produce steam to turn a turbine. Generators in dams are one exception, and of course solar cell generation is another.
But who came up with OTEC and why has it taken so long for a small plant to be built? We answer that next…
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