On a breezy mountain in Garrett, Pennsylvania, 170 local teachers crowd around Harold Nicholson in the shadow of a 70-meter windmill. Nicholson, who gives tours of the eight-turbine Green Mountain Wind Farm, is explaining how the facility operates.“The 10.4 megawatts this facility creates yearly, compared to conventional power, saves 17,000 tons of carbon dioxide from going in the air,” says Nicholson. “That’s the equivalent of driving 42 million miles with your car.”
Inside one of the 70-meter towers David Lohr, a wind-farm technician, traces the process of generating electricity from wind: The three 30-meter blades turn, powering a generator in the tower, which sends electricity to a transformer, then down to a substation at the entrance to the farm. The substation feeds power directly into the PJM (Pennsylvania Jersey Maryland) electrical grid. The grid serves 23 million people. This wind farm produces enough power for 2,500 Pennsylvania homes.
A Bountiful Supply
Currently, the U.S. generates about 0.1 percent of its power using wind-a minuscule contribution, especially compared to Denmark’s 10 percent. The Department of Energy wants to increase wind’s contribution to U.S. energy production to 5 percent by 2020.
The problem won’t be one of raw supply. According to the National Renewable Energy Laboratory’s National Wind Technology Center, North Dakota alone, sometimes called the Saudi Arabia of wind power, has enough wind to generate electricity for about one third of the continental U.S. “There’s no shortage,” says center director Robert Thresher.
Cost, however, is an obstacle. “It currently costs three to five cents per kilowatt-hour to produce electricity using wind,” says Thresher. “If we could reduce cost below three cents per kilowatt-hour, at sites with an average windspeed of 13 mph the cost would be competitive” with conventional power generating technologies.
Small boosts in wind speed can go a long way. Power output increases in proportion to the cube of the wind speed. So a windmill at a site where the wind averages 25 kilometers per hour will yield twice as much power as one sited amidst 20 kilometer-per-hour winds. Windmills with rotors that can turn and actually hunt for wind increase efficiency. So does smarter placement of the windmills. Recently researchers have recommended staggering windmills rather than placing them in rows, which create a shadowing effect.
Barriers to Adoption
The wind power generated today isn’t stored, but instead flows directly into the grid. That’s a big drawback: if there’s no wind, there’s no juice. While most researchers aren’t currently focusing on storage, some are investigating various options like fuel cells, hydrogen and battery storage.
David Sears is vice president of Aeromax, a Prescott Valley, AZ, company that develops small and medium-sized wind turbine generators. Sears’s company is testing a design that would use wind power to compress air, which could then be stored. When power was needed, the compressed air could run an air motor. “You could set up compressed air to pump water, or run a sewage treatment, or an offshore desalination facility,” says Sears.
Sears says his company is talking with the U.S. Air Force as well as IT companies to replace some of their generators with wind turbines, coupled with compressed air motors to replace diesel units.
Proponents of wind energy argue that the technology is still effective despite the lack of a steady supply. When wind power isn’t available, they maintain, electricity can be produced using conventional means such as hydropower. Conversely, these conventional forms of power can be cut back as wind power increases.
“The more wind farms you build in an area, the more you can reduce the fluctuations,” says Brian KillKelley, a senior energy analyst at Green Mountain Energy Company. “It may stop blowing at your one location, but 200 or 500 miles downstate it’s still blowing.”
Large-scale expansion of wind technology will depend in large part on federal largess. Subsidies and tax credits “can change the economics dramatically,” says Steve Fetter, professor at University of Maryland’s School of Public Affairs and board member of the Washington, D.C.-based Sustainable Energy Institute. “Several countries in Europe are experiencing booms in wind power, largely because of price supports for wind electricity,” says Fetter. “A significant carbon tax would greatly benefit wind.”