20 December 2007

Wave Power

Wave power is derived from solar energy--by way of the wind. It is a constant, 24 hour energy source, so unlike solar and wind, waves could potentially serve as baseload power. Several approaches to tapping ocean wave power have been tried, none particularly useful so far. One ongoing project off the California coast may merit attention.
Pacific Gas and Electric Company has announced that it has entered into a long-term, two megawatt (MW) commercial wave energy power purchasing agreement with Finavera Renewables Inc. Located off the Northern California coast, the Humboldt County Offshore Wave Energy Power Plant will be developed by Finavera Renewables. The project is expected to begin delivering renewable, clean electricity in 2012.

“Harnessing the ocean’s energy on a utility scale is a critical achievement in renewable energy technology and this project represents our first step in that direction,” said Fong Wan, vice president of Energy Procurement, PG&E....Finavera Renewables has initiated development plans for the two megawatt wave energy project to be constructed approximately 2.5 miles off the coast of Humboldt County, California
One of more interesting proposals for transducing wave energy to electric power comes from SRI International.
The concept derives from the discovery a little over a decade ago of so-called dielectric elastomers, stretchy plastics that react to and generate electricity. When electricity runs through an elastomer, the elastomer compresses and contracts, much the way a muscle does. It didn’t take long for researchers at SRI International, a nonprofit organization based in Menlo Park, Calif., to realize that the process would work in reverse: stress and relax the elastomer, and it will generate electricity....Imagine a cable of elastomer with one end tied to the ocean bottom and the other attached to a buoy on the surface. When the buoy rides up a crest of the wave, it stretches the elastomer. When it sinks into a trough, it contracts and then generates a pulse of electricity.

So far, the energy generated is on the order of watts, not kilowatts. But SRI is not an organisation to give up too easily. In fact, a wide range of companies, corporations, and other organisations are vying to make wave power a viable commercial enterprise.

The UK Department of Trade and Industry projects that wave power could by 2025 produce 20% of the UKs power electric power demands.

Wave Energy Resource Links:

Wikipedia Wave Power
Peswicki Ocean Wave Energy Directory
Alternative Energy News: Wave Power
Wave Energy Centre Resources
Wave Power OCS White Paper

While nations with a large coastline, such as the UK, can profit from wave and offshore wind energy, the killer app for such energies is the "seastead". A floating island, well away from land, would be in an optimal position to exploit wave power, sea winds, and OTEC. The full energy repertoire of a large seastead would include ample PV, solar thermal, and possibly small scale nuclear.

A seastead is a seagoing version of a relatively self-sufficient city-state. As most regular Al Fin readers know, many trends in current events are leading toward an era when the city-state becomes important again in world affairs. Singapore is the best example of a contemporary city-state, although Hong Kong has the potential to be another, should the mainland communists lose their vampire's grip.

Most modern nation-states are entirely fossilized in their present form. Only a large catastrophe would lead to the disintegration of most western nation-states. Should that catastrophe occur, the cities and regions that had made prior planning for at least temporary self-sufficiency, would ride the aftermath with the least bloodshed and suffering.

Floating seasteads have the potential to carry their own coral reefs and fish/edible sea creature breeding grounds in the flotation undercarriage--so healthy aquaculture should be easily possible. Energy supplies should be no problem, given the diverse and relatively constant nature of renewables available. Food crops could be grown via aeroponics/hydroponics, so there would be no need to hoard soil (as in "Waterworld"). Freshwater could be supplied via solar distillation, OTEC flash distillation, nano-facilitated electrolysis, etc.

In the case of a killer pandemic or nuclear fallout contamination of large cities and croplands, a floating seastead would provide the type of isolation that might allow the survival of fairly large populations. A successful large-scale seastead would also involve large scale underwater operations--giving scientists a perfect testing platform for various technologies useful in a permanent undersea habitat.

Those readers familiar with Marshall Savage's Millenial Project will remember that the Aquarius seastead was the second out of 8 steps to colonise the galaxy.

I see the seastead as a floating example of an "arcology" in the broader sense. The arcology concept can be useful for a land-based semi-autonomous city-state, a seastead, an undersea city, an orbital colony-city, a sustainable moonbase, etc.

A good question to ask: what is the smallest human population that can be sustainable technologically, genetically, societally, culturally, etc. The answer would be a bit different, depending upon the topology, resources, and room for expansion. With advances in genetics, the danger of inbreeding in a small population would be more controllable--but that level of genetic control is well in the future.

More on these idle speculations later.

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