To justify the destruction of Maine’s landscapes with his wind turbines, Angus King repeats the familiar claim (June 30) that there would be a one-to-one reduction in greenhouse gases because existing plants would be throttled back whenever the turbines are in operation.

This is simply not true. To understand why, consider that the grid is like the generator many of us have for emergency use. If you plug a 1,500-watt space heater into a 1,000-watt generator, you have overloaded the generator by 500 watts and the circuit breaker will trip. Plug the same heater into a 2,000-watt generator, and you have 500 watts of unused capacity. Unused capacity in the electrical grid is known as “spinning reserve.”

The grid operator maintains enough spinning reserve to ensure that if one of the largest generators suddenly fails, or demand increases unexpectedly, there will be no tripped breakers. The grid operator does not react to every flip of a light switch, it simply provides more than enough generation at all times.

The grid operator is not required to reduce fossil fuel generation when the wind blows. Its primary job is to provide reliable electricity.

ISO-NE has been studying the problems of integrating uncontrollable wind power for several years and has not found a successful fossil fuel reduction program. Wind power, when available, often simply adds to the safety buffer known as spinning reserve. In grid terms, it is “spilled” or wasted.

Steve Thurston, Roxbury

Editor’s note: Steve Thurston is co-chairman of the Citizens Task Force on Wind Power in Oquossoc.