Hawaii, I think, is leading the country in using renewable energy.

The Big Island has a working power plant that uses ocean thermal energy conversion to generate power using the difference in temperature between cold ocean water on the bottom and the warmer water on the top. Two new such plants are in the works, as the rising price of oil now makes it economical.

The process requires two sources of water with a fairly large difference in temperature. At the Natural Energy Lab, warm water is piped from the surface of the ocean where it can be used to vaporize a liquid such as ammonia, which then drives a turbine to produce electricity.

At that point the ammonia has to be cooled and condensed to continue the cycle.

A byproduct of the OTEC process is production of fresh water from ocean water. OTECNews blogs about the latest in the field. I wonder, is there an environmental impact on ocean life from constant recirculation of the warm/cold water?

In other renewable news, Hawaiian Electric is prosing a 110MW power plant on Oahu that will run entirely on biofuel made from processing leftovers from agricultural products “such as corn, soybeans, sugar and their byproducts.”

[tags]OTEC,biofuel,ocean thermal energy conversion[/tags]

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