At whim of the wind

A hidden cost of wind power is that it requires full backup from conventional power plants for those times when the wind does not blow sufficiently or when it blows too strongly.

Gov. Deval Patrick has declared a goal of 2,000 megawatts of wind power by the year 2020 and the state has engaged in significant programs to achieve that goal, including soon-to-be-finalized legislation that, among other things, weakens the power of town boards from permitting decisions. Lost in this activity, however, is a critical examination of the downside of wind power and whether the 2,000 megawatt goal should actually be pursued.

The issue is that pursuit of the goal has the potential to convert thousands of acres of the state's land and water into industrial tracts - all for the purpose of generating low quantities of expensive and unreliable electric power. This may be acceptable in the Midwest with its open agricultural spaces, but in Massachusetts will likely mean the destruction of forested lands and scenic vistas.

Wind power is expensive because the wind blows for only some of the time and, when it blows, it blows at optimum speeds for only some of the time, resulting in annual average power generation levels of only 20 percent to 35 percent of rated capacity. For example, multiple wind plants totaling 2,000 megawatts of capacity will not generate 2,000 megawatts of power over the course of a year, but will instead result in an average generation rate around 600 megawatts or less - equivalent to the output of a single 670 megawatt conventional power plant. The difference is that the conventional plant provides its power reliably while wind plants provide power literally at the whim of the wind.

A hidden cost of wind power is that it requires 100 percent backup from conventional power plants for those times when the wind does not blow sufficiently or when it blows too strongly and wind turbines shut down to protect mechanical components. Moreover, all power plants require electric power for internal processes. This means that when the wind is still, such as on a hot, muggy July day, wind plants can actually consume power from the grid.

Wind plants can be successful, such as two publicly-owned turbines in Hull located on town land and providing power to the municipal light department. This situation is unique, however, and not readily replicated. At the other end of the spectrum is a publicly-owned wind turbine in Saco, Maine, which, according to Saco's Sun Chronicle, was built at a cost of $210,000 but generated only 27,545 kilowatt-hours - around $5,000 worth of power - over its two years of operations before being shut down.

Wind turbines require significant clear space around them to get an unobstructed flow of wind. The space use for the proposed offshore Cape Wind project in Nantucket Sound is around 35 acres per megawatt, similar to a typical land-based project at 33 acres per megawatt (less if the project were on a ridge line or shore line). This translates into a need of around 68,000 clear acres of our forests or waters to meet the governor's goal of 2,000 megawatts of installed capacity - all for power that can be met by a single 670 megawatt conventional plant on 150 acres.

The state's push for wind power has been justified as a means to reduce atmospheric emissions and carbon dioxide generated from conventional power sources and to reduce our reliance on foreign oil. But conventional sources already include technologies that achieve these objectives while providing reliable power to the grid - something necessary to attract and maintain jobs in the state and to support societal needs. So let's drop the arbitrary goal, the expedited permitting legislation and state-derived push, and let wind turbines take a natural course of development subject to full and critical evaluation. That's the green way.

Robert Pease is president of Pease, Snow & Associates, Inc., an environmental consulting firm in Chelmsford.