Q. How much wind farm to power New York City?

A. TWO HUNDRED TIMES the space of Manhattan:

At www.scitizen.com, Kurt Cobb worked the numbers. Generously, he presumed the windmills would use 5-megawatt turbines – generating three times the output of a typical 1.5-megawatt turbine. He compared that with a 500-megawatt fossil-fuel (coal) power plant needed to power a city of 300,000 people. A typical power plant, he noted, would cover 300 acres, but use only 30 of those for the actual facility.

Cobb calculated it would take 233 5-megawatt wind turbines to equal the coal plant's output, since the wind doesn't blow constantly. Each would need to be spaced 2,065 feet away from the others (five times the diameter of their 413-foot rotors). Adding the rotor diameters to the spacing requirement equates to a 110-mile long line of windmills, half a mile in width.

It comes to 55 square miles. That's to provide electricity for a town of 300,000 people.

New York City has 8.1 million residents. Manhattan Island totals 23 square miles. So, based on Cobb's calculations, it would take six and a half Manhattan Islands, each covered totally with windmills, to power one-tenth of New York City. And if standard 1.5-megawatt wind turbines were used, they would take three times more space.

Mayor Bloomberg's vision is flawed. But it's typical of the pie-in-the-sky energy "solutions" suggested by those who would rather "go green" than "get real."(Bloomberg looks positively reasonable compared to the Australian engineer who proposed a giant helicopter carrying wind rotors 15,000 feet into the sky, and sending back electricity through a tether wire super-sized extension cord!)

Going back to Kurt Cobb's calculations, if we wanted to meet the electric needs of 300 million Americans rather than only 300,000, we'd need a half-mile swath of windmills, each of them hundreds of feet high, 110,000 miles long, crisscrossing the continent 40 times between New York City and Los Angeles.

That's a lot of land to condemn. The cost would be in the hundreds of billions of dollars, since each large windmill costs millions.

National Wind Watch calculates that wind power consumes an average of 50 acres per megawatt when you include the need to remove trees in the vicinity. On that basis, powering America with wind means we'd have to cover Nebraska with wall-to-wall windmills, leaving no room to grow corn (and thus threatening ethanol).

But even if it were practical (and affordable) to convert to wind power on such a massive scale, it generates other consequences, both aesthetic and scientific .

New York State's largest windmill farm to date, the $400 million Maple Ridge project, features 195 medium-size (400-foot high) windmills, part of a windmill surge in upstate New York sparked by state and federal incentives. That project has generated great controversy even in its rural setting. According to area researcher Dr. Nina Pierpont, it has also created "wind turbine syndrome," a variety of ills such as inner ear problems, headaches, difficulty sleeping, ringing in the ears, mood disorders, irritability, panic attacks and child misbehavior, all attributed to the low-frequency rumblings of the windmills.

There are practical problems, too. If the structures are put totally in the boondocks, massive new transmission lines must be built to carry the power to where the people are.

Thanks to Bruce McQuain.