While the concept of Ocean Energy Thermal Conversion goes back 40 years or more and resembles in some ways the thermal conversion systems used for land-based buildings, the ocean based version seems not to have grown substantially since this report from 2015. Today, Maki Ocean Engineering continues to bring innovative energy solutions to clients around the world and currently, their operating system is feeding power into the Island grid. Plants operating in Japan and elsewhere continue to operate on an experimental basis and the future remains to be determined.
REPORT FROM 2015
The OETC plant built by Maki Ocean Engineering in Hawaii is the largest of its kind in the world and is expected to produce power for up to 120,000 homes on the island, which has a population of around 1.4 million people.
How does it work? At the heart of the OTEC system is ammonia, which has a low boiling point compared to other liquids. First, it passes through pipes surrounded by warm water, which causes the ammonia to evaporate into a gas which then powers a turbine and generates energy. Freezing cold water taken from the ocean depths is used to reverse the process, returning the ammonia back to liquid form, and again powering turbines as it falls. Afterwards, the water is pumped back into the ocean.
Eventually, Maki Ocean Engineering wants to move its new plant from its current location at the Natural Energy Laboratory of Hawaii Authority (NELHA) further out into the Pacific Ocean, which would mean the pumped water having less distance to travel. The company estimates that 12 commercial-scale plants like this could provide energy for the whole of Hawaii.
One of the benefits of this type of technology is that it can run around the clock, with no peaks or troughs in supply. But the plant is still being treated as an experimental test run to see if OTEC can meet its potential more than 100 years after it was first proposed. Similar schemes are currently in operation in Japan and South Korea as well.
- Hawaii’s newest power plant uses ocean temperatures to generate energy – Science News Post