The horizon in Denmark

The Boston Globe - Boston.com - Editorials - News: "THE BEST way to tell which way the wind industry is blowing is to visit a wind farm built here two decades ago with 101 turbines that are now considered the antique Model As of the technology. As equipment fails in these small units, they are dismantled for scrap. Wind turbines are getting bigger and moving offshore. The reasons help explain why Nantucket Sound, the proposed location for Cape Wind's major wind farm, is superior to a proposed alternate site: the Massachusetts Military Reservation on Cape Cod.

The biggest of the Velling farm's Model As turn out 100 kilowatts, enough to power 25 to 30 average US homes. By comparison, the Danish turbine installed in 2001 in Hull puts out 660 kilowatts. The 130 turbines proposed by Cape Wind for Nantucket Sound would generate 3.6 megawatts each, 36 times as much as the biggest of this rudimentary wind farm.

A simple calculation pushes turbine designers toward bigger and bigger windmills: Energy production increases in proportion to the square of the blades' surface area. From afar, the blades look leanly graceful, but the big new ones are more than 6 feet wide at the point where they join the tower. The blades then taper to a point more than 60 yards away, cutting a circle bigger than a football field, with end zones. The nacelles -- the pods at the top of the towers that house the generator, transmission, and transformer -- are as big as school buses.

Physics is also driving wind harnessers to offshore locations like Nantucket Sound. Turbines' production increases in proportion with the cube of wind speed. This means that the 17.5 m.p.h. wind on the sound is not just fractionally better than the 15 m.p.h. wind on land at the Military Reservation. The offshore wind would produce 59 percent more power than land wind. Moreover, the offshore wind blows more consistently, producing less wear and tear on the turbine machinery.

A global map by two Stanford University scientists has found that Northern Europe and North America, especially its coasts and the Great Lakes, are blessed with wind well suited to power production. The two, whose article ran in the Journal of Geophysical Research-Atmospheres in May, measured wind speeds from 7,500 surface locations and 500 balloons suspended at 300 feet, a typical height for a turbine.

Public and private energy planners in the United States should be using their map and other data to locate this country's best locations for wind farms. Once these are identified, and once Congress realizes that slowing climate change requires capping carbon emissions or taxing them for the damage they cause to the environment, wind should play a much bigger role in this nation's electric power supply.

DONALD MacGILLIS"