Offshore wind power is the Holy Grail of renewable energy: It’s clean, abundant, and out of sight. Now that energy security is meshing with environmental concerns inside the White House, is offshore wind power ready to come of age?
Probably not as fast as wind-power boosters would hope. If the economics of onshore wind are tricky enough to give T. Boone Pickens pause, the challenges facing offshore wind are even greater.
Take the new proposal for the world’s biggest wind farm by another Texas oil man, peak oil prophet Matt Simmons. His Ocean Energy Institute proposes building a 5,000 megawatt deepwater wind farm in the Gulf of Maine, blessed with some of the world’s strongest sustained winds.
The problem is that, as envisioned, the Maine offshore wind farm would be very expensive—and that vision includes some very optimistic assumptions.
Ocean Energy figures capital costs for the project could go as high as $4.5 billion a megawatt, a lot more than Mr. Pickens projects for his massive Texas wind farm. All in, the costs for the Maine project could come to $25 billion, or $5 billion a megawatt, the Ocean Energy folks told Earth2Tech. That compares to upfront costs of about $600 million per megawatt for old-fashioned coal-fired plants.
The theory is that stronger winds offshore will help make up that cost differential. Since wind farms, especially in deep water, will produce more electricity than their onshore cousins, the costs per kilowatt hour will be competitive. Ocean Energy assumes its deepwater wind turbines will have a “capacity factor” of 45%, or about half what a nuclear power plant has.
Few others are so optimistic. Offshore turbines exposed to stronger winds more months of the year also take a battering, which leads to downtime for additional maintenance and repairs, pushing total output back down.
The European Wind Energy Association figures offshore wind in the future could reach a capacity factor of 40%. In Britain, where the government hopes a raft of big, offshore wind farms will help the country meet its renewable-energy targets, experts figure offshore wind farms get about 33% capacity. In practice, U.K. offshore wind farms tend to produce between 25% and 35% of the listed power capacity. That’s not much better than cheaper onshore wind farms, which average about 27% in the U.K.
The bottom line is that for offshore wind to become a realistic part of the energy mix, three things have to happen. The government has to put a really big pricetag on greenhouse-gas emissions to penalize dirtier but cheaper sources of power. Wind turbines have to be made more robust and reliable without increasing their cost. And the wind industry has to find enough offshore and deepwater equipment to install hundreds of huge machines even as the oil industry presses ahead with its own deep-water exploration, putting offshore equipment at a premium.