There have been stories and letters in The Sentinel extolling the merits of wind power and its contributions to our energy mix. It’s unfortunate that wind energy has ever risen in energy discussions, because it suffers a serious, fundamental and likely insoluble problem.
This problem is sufficiently serious as to question whether wind energy should ever be considered to contribute meaningful electrical energy to New Hampshire. Legislatively forcing wind to contribute more than 1, 2 or 3 percent of our electricity requirements will destroy the ISO-New England electric grid, as can be shown from two simple observations about wind and wind turbines. Neither of these observations is in dispute.
First, wind speeds vary from calm to hurricane force, guaranteeing the electrical energy produced by wind turbines and sent to the New England grid, will vary between zero and very large values. Second, these winds are highly synchronized over New England, guaranteeing that almost every wind turbine in New England will spin at about the same speed — fast or slow — but together. That means sometimes they will all send little or no wind energy to the grid, and at other times they will overwhelm the grid with large surges of electricity.
Wind turbines are only one-third efficient. A large turbine, 1/10 of a mile high, can produce 3 megawatts of electric power in brisk winds, but it will average only 1 Mw. This one-third efficiency requires the installation of three times the number of turbines required to be 100 percent efficient. But when the winds are brisk, every turbine in this tripled installation will combine to produce a tripled surge, large enough to overwhelm the grid.
To get an average of 5 percent of our energy from wind means that wind power will actually produce between zero and 15 percent, depending on how windy it is. Our legislators have mandated that wind turbines contribute some percentage of our electric energy, 5 percent, 10 percent, 25 percent or more. That means the day-to-day contribution from wind will actually vary between zero and three (the inverse of one-third) times that percentage: 15 percent, 30 percent, 75 percent or more. The New England grid cannot handle such surges, expected a couple of times every week.
Variations in wind are largely synchronized over New England, producing unacceptably large electrical surges from wind turbines, and thereby limiting windmills to a minuscule energy role.