Thursday, April 29, 2010

Economic and policy analysis of wind power

I'm having trouble locating the exact factoid of "total annual U.S. wind output equals output of one medium-sized coal-fired power plant," but I'll keep looking. In the meantime, here is a fairly thorough economic analysis of wind power at . Highlights relevant to some of our discussion this morning include:
Often, the most favorable locations for wind farms also happen to be the current location of particularly spectacular views in relatively unspoiled areas. Wind farms that produce only a fraction of the energy of a conventional power plant require 100 times the acreage. For instance:

Two of the biggest wind "farms" in Europe have 159 turbines and cover thousands of acres; but together they take a year to produce less than four days' output from a single 2,000 MW conventional power station - which takes up 100 times fewer acres.

A proposed wind farm off the Massachusetts coast would produce only 450 MW of power but require 130 towers and more than 24 square miles of ocean.

A wind farm occupying 192,000 acres - 300 square miles - would produce the same amount of energy as a 1000 MW nuclear plant (which has less than 1700 acres, or 2.65 square miles, within its security perimeter fence), or as a 1000 MW coal powered plant taking up 1950 acres, 3.05 square miles, for all of its associated infrastructure.

Also, wind power requires the continued existence of conventional power plans for storage and backup:
Because of intermittency problems, wind farms need conventional power plants to supplement the power they do supply. Bringing a conventional power plant on line to supply power is not as simple as turning on a switch; therefore most "redundant" fossil fuel power stations must run, even if at reduced levels, continuously. Accordingly, very little fossil-fired electricity will be displaced and few emissions will be avoided because fossil-fueled units (operating at less than their peak capacity and efficiency or operating in "spinning reserve" mode - which means they are emitting more pollution per energy produced than if operating at peak efficiency, imagine a car idling near train tracks in case the power goes out) must be kept immediately available to supply electricity when the output from wind turbines drop because wind speed slows or falls below minimums required to power the turbines. Kilowatt-hours produced by wind turbines cannot be assumed displace the emissions associated with an equal number of kWh from fossil-fueled generating units. Combined with the pollutants emitted and CO2 released in the manufacture and maintenance of wind towers and their associated infrastructure, substituting wind power for fossil fuels does not improve air quality very much.
So these are tough issues. Hard to say what is the "best" policy outcome in this case. But clearly here is a case where real-life aesthetics problems come into sharp focus.

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