Exquisitely expensive offshore wind farm to begin turning in October

To understand the size and extent of visual pollution, notice the small size of that work basket which would hold many people. Photo courtesy of Adobe Stock.
To understand the extent of visual pollution and danger to navigation, notice the small size of that work basket which is large enough to hold many people. The rails are probably about four feet high. Photo courtesy of Adobe Stock.

New York Times reports on 8/22 that America’s First Offshore Wind Farm May Power Up a New Industry – In a very upbeat puff piece, the NYT describes the Block Island Wind Farm project, which is expected to start producing electricity in October, after construction was recently completed. The turbines will start turning in October and after weeks of fine tuning (to get the phase output from each turbine identically matched and to resolve other technical issues), will start pumping out electricity.

Photo in the article shows the turbines are extremely visible from the island. If you didn’t know they are about 589 feet tall, you might guess the turbines are a half mile or mile offshore. They are actually three miles away.

Article says the wind in offshore locations is more steady than on land, so the capacity realized should be far higher than for slice-and-dicers built on land.

Article says there are about 50,000 onshore turbines installed in the U.S.

This will be an exquisitely expensive project. I’ve previously discussed the construction costs of the turbines are somewhere around $11.3M per megawatt for the theoretical capacity of each one of the thirty megawatts. The 20-mile long undersea cable connecting the island to mainland will cost $3.6M for each megawatt of capacity.

That brings total cost to about $14.9M per megawatt capacity.

Contract for the electricity starts at above market and will rise 3.5% a year for the next 20 years, according to the source article linked above.

To put this in perspective, here are some “overnight capital costs” for building various capacities of electricity generation, according to EIA, as discussed before.

  • $1.0M/mW – conventional combined gas turbine
  • $2.0M/mW – wind onshore
  • $6.2M/mW – wind offshore, according to the report; data refuted by this project
  • $5.4M/mW – advanced nuclear

So the brand new, state of the art, future-is-glorious offshore project at $14.9M per megawatt is fifteen times more expensive than a gas turbine and 2.8 times more expensive than nuclear.

Yes, if it were possible to scale down a nuclear reactor, the folks on the island could have almost three times as much power from a nuclear plant as from the soon-to-turn offshore turbines. Carbon output during operation would be the same too.

Or, for one-fifteen of the construction cost the island residents could have always-available electricity from a natural gas turbine.

Oh, also keep in mind there will need to be 30mW of gas turbine capacity on land to back up the offshore turbines for the days when wind isn’t blowing within the correct parameters, neither too fast (requiring the turbines to be feathered) nor too slow (requiring purchase of electricity on the spot market). That merely brings the defacto economic construction costs from $14.9M/mW to effectively $15.9M/mW. Eh. A million more per megawatt isn’t material to offshore wind power.

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