Wind opponents need to get facts straight
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By AVRAM PATT - Published: February 18, 2007
In the Feb. 11 edition of the Sunday Rutland Herald and Times Argus, Bill Metcalf writes about the noise level of wind turbines. From what I know, I think he is misstating some things about decibel levels, but I am not a sound expert. I am writing because Metcalf misrepresents one fundamental fact about the amount of energy that commercial scale wind turbines generate, and the amount of energy from other sources (fossil fuels and/or nuclear) that wind energy displaces. He is wrong, and the calculations in Metcalf's letter show exactly what the obvious error is and why this assertion misleads people, despite his statement that he is "a capable interpreter of technology."
I recognize that most people don't really understand power supply and how it is measured and paid for. But opponents of wind energy who have been studying and researching the effects of the many thousands of wind turbines now operating in North America, across Europe, Asia and elsewhere should know better by now. After a certain point people involved in an important public debate have an obligation to get fundamental facts right when publishing their arguments in newspapers. They may still oppose a project for other reasons, but it's not right to keep repeating things that don't add up.
I'll try to keep this simple. Metcalf confuses "capacity" with energy. "Capacity" is a piece of machinery's horsepower rating. That is a very different thing than the amount of energy it actually produces during an hour or a day or a year. A piece of machinery may have the capacity to generate 2.0 megawatts for example. If, theoretically, it ran every hour of the year, it would generate 17,520 megawatt hours (or about 17.5 million kilowatt hours) annually. But if the same 2 MW machine only ran 300 hours a year for example (as some fossil fuel plants used only during brief periods of peak demand do), the machine would only generate 600 megawatt hours (600,000 kWh). When it is not running, it still has the same capacity or horsepower, but it is not using any fuel.
As consumers using electricity for lights, toasters or in factories, we use and are billed for kilowatt hours, and at a utility, we add everyone's needs up together into megawatt hours. The utility system must assure that there is a whole lot more generating "capacity" (horsepower), installed than we use most of the time, for reliability reasons and to make sure we can keep the lights on during a peak.
Metcalf wrongly uses capacity instead of energy in his calculation, as do other people who mistakenly assert that wind energy doesn't make much of a difference. Commercial wind energy can replace a significant part of the energy that has to otherwise be generated using a fuel of some kind. It does not displace as much need for capacity, but as I've explained, "capacity" is not what burns fuel.
A car's motor has a certain horsepower rating, but it only burns fuel when we need to go somewhere. If we decide to ride a bike, walk or carpool instead, the car is still sitting there with its same capacity, but we haven't asked it to do any work and it's not using any gas.
Whenever wind turns the blades of a turbine over the course of an hour, it produces megawatt hours (or kilowatt hours.) If the turbine was not there, another kind of generator would be called on to do that work, and in our region, would most likely burn a fossil fuel (natural gas or to a lesser degree diesel). To summarize this as simply as possible: Every moment a wind turbine is turning (which is most of the time); fossil fuels are not being burned. Over the course of a year, the Sheffield project would replace the amount of energy coming from such other sources equivalent to what 15,000 homes use. That is a big improvement over the way things are now.
If people feel commercial wind turbines have a negative impact for other reasons, that should be debated. But such serious errors about how much clean energy the turbines generate needs to be corrected.
Avram Patt is the general manager of the Washington Electric Coop.
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