April 26, 2015


Catching Waves and Turning Them Into Electricity (AMY YEE, APRIL 22, 2015, NY Times)

The constant rocking of the ocean drives hydraulic pumps that push seawater and other liquids through a pipe to a power plant nearly two miles away on Garden Island. There, the high-pressure water turns standard hydroelectric turbines, which power a generator.

Wave energy from the buoys also pumps high-pressure water through the desalination plant, without using fossil fuels. In contrast, many desalination plants use diesel fuel or electricity to pump saltwater at high pressure through membranes to yield fresh water.

Carnegie is already planning to start using larger, better-designed buoys in 2017 that could each generate one megawatt of electricity. The new technology, called Ceto 6, would use buoys 65 feet wide that could produce four times the energy of the current prototype.

The new technology would generate electricity inside the buoy instead of at an onshore power plant. The electricity would be carried to shore by underwater cables, rather than by pumping water through a pipe. These larger buoys would also sit in deeper water, more than seven miles from shore, where waves are larger and have more energy. The newer buoys would be easier to maintain because they would be self-contained units that could be towed back to shore.

Ceto 5 uses heavy machinery on the sea floor next to each pump to smooth the flow of the piped water. Because no water is pumped with the newer buoys, this equipment is not needed. Ceto 6 is expected to generate 30 to 40 percent of the naval base's electricity at a cheaper rate.

Carnegie estimates that using the improved buoys in large wave farms of 100 megawatts would reduce rates to 12 to 15 cents a kilowatt-hour -- a price comparable to commercial electricity in the state of Western Australia.

Posted by at April 26, 2015 10:34 AM

blog comments powered by Disqus