New Scottish Wave Energy Generator Unveiled 244
MikeChino writes "We've learned about Scotland's wave energy initiatives in the past, and just this morning the nation unveiled Aquamarine Power's next-generation Oyster 800 wave power plant. The new generator can produce 250% more power at one third the cost of the first full-scale 315kw Oyster that was installed in Orkney in 2009. The device's shape has been modified and made wider to enable it to capture more wave energy, and a double seabed pile system allows for easier installation."
For comparison (Score:4, Informative)
Onshore wind farms have a 20%-25% capacity factor. Offshore wind seems to have a 30%-40% capacity factor, with turbines in the 1 - 4 MW range. So this wave power unit will on average generate slightly less energy than one of the smaller offshore wind turbines. In the KE = 0.5mv^2 equation, water has about 800x more mass than air, but the average wind speed is a lot higher than the average speed of the waveheight up and down. Enough so that it seems wind ends up having the advantage. (This is just a comparison, not a trade-off. You could for example install these wave power machines in between your offshore wind turbines.)
Comparing to conventional energy sources, the typical coal plant in the U.S. is about 340 MW with a 65% capacity factor, for about 220 MW average generation. So that's about 800 of these wave energy generators. The typical nuclear plant is about 1.55 GW with a 90% capacity factor, for about 1.4 GW average generation, or about 5000 of these wave energy generators. So we've still got a long way to go before these can truly replace conventional energy sources.
Unfortunately I can't find the price for one of these units, probably since they're still very much in the R&D phase. So I can't do a cost comparison. Also note that the Wikipedia entry for this project says it has three flaps each of which is capable of 800 kW. So depending on if the summary or wikipedia is right, the average power generated may be a factor of 3 higher.
Not stainless steel I hope (Score:5, Informative)
However, it's a myth that stainless steel is the best thing for salt water. It is fine for above-deck use because it gets washed clean by freshwater in rain. But the interesting ingredients of seawater can cause pinholing and stress corrosion in stainless steels, though A4/316 is better than most. Bronze (tin/copper alloy) is good and is traditionally used for throughhulls and seacocks. The usual solution (pun intended) is of course not to let seawater near any working fluid circuits but to use either hydraulic oils or a mixture of propylene glycol and water (anti-freeze) - use propylene rather than ethylene because it doesn't kill fish if it leaks out.
Corrosion engineering is a really fascinating discipline with many unexpecteds and gotchas.
Re:Unfortunately... (Score:5, Informative)
As a Scotsman I'm offended at your derogatory and cliched view of my country. The energy is used to power deep-fat fryers, whisky distilleries and cigarette vending machings. Some energy is left over for TV sets in to watch our football team being crushed by all but the tiniest nations.
Re:That's nice... (Score:4, Informative)
That's when we turn on the link to Shetland, where the wind never stops blowing!
The what?
We move to option number four, tidal, which is being trialled [scottishpo...wables.com] in the Sound of Islay. Tides are predictable - you know exactly when the energy will peak and trough, and can plan for it. In an ideal world we'd have tidal as our base generation, with the troughs supplemented by other forms of renewable energy buffered by pumped storage.