Ocean thermal energy conversion, or OTEC, uses seawater to turn solar energy into electricity. It relies on the ocean’s thermal gradient – the temperature decline from the sun-warmed waters on the surface to the cold waters found at great depths. OTEC plants pipe in hot and cold seawater and run them through heat exchangers and water condensers, in the process spinning turbines that generate electricity. It can only be done efficiently where the thermal gradient within the upper 1,000 meters of the ocean is more than 20° Celsius. These conditions occur in most of Earth’s tropical seas.
The concept of OTEC power is enormously appealing. Sunlight is free and renewable every morning. And scientists estimate that OTEC has the potential to generate billions of watts of electricity. Yet only a few, mainly experimental, plants have been built. One of the problems that restrict OTEC is that the necessary thermal gradient is found at sea, but the power it can generate is needed on land. In this activity, you will examine some of the issues involved in this dilemma by comparing onshore and offshore OTEC facilities.
Is the ocean the real final frontier? Humans have a greater understanding of the surface of the moon than they do of the depths of our ocean. But what we know of the ocean proves it hosts a wealth of opportunity – connecting the world; supporting important and basic economic, cultural and environmental functions – despite being under significant threat. Stressed by unsustainable lifestyles and the increasing demands of a growing global population, how do we become good stewards of this massive natural resource?
In the massive open online course One Planet – One Ocean: From Science to Solutions, learn from the world’s leading experts on ocean science. They will present the issues and potential solutions – grounded in rigorous scientific research – to fight for our endangered waters.
For more information: https://oceanexplorer.noaa.gov/edu/learning/player/lesson11/l11la1.html