Making Wind Work
Wind energy has been used to improve quality of life for thousands of years. Wind turbines were first used to generate electricity in Denmark as far back as 1890, and multi-bladed mills became a symbol of rural America in the early 1900s. Last year, enough wind was harnessed to power almost 10 million American homes (roughly 35,000 MW).
With help of tax credits and federal funding, wind power costs have dropped from 80 cents per kilowatt-hour (kWh) in 1980 to 8 cents per kWh in 2009. (In comparison, the cost for electricity from coal-fired power plants averages 3.6 cents per kWh; nuclear power roughly 2.1 cents per kWh; and natural gas, 7 cents per kWh.) As the generation becomes more affordable, wind power plants in some parts of the country—often called wind farms—are now as common as weather-beaten windmills of the past.
How to Harness Wind
Wind power follows a basic premise: if you can turn a generator, you can produce electricity. Turbines convert the natural energy of wind into mechanical energy by attaching giant, wind-catching blades to a generator. When wind blows through the blades, they spin and generate power.
The most common are horizontal-axis varieties, which look like a large pinwheel or fan. A typical model sports three blades, facing into the wind. Some small turbines that can be erected in a backyard to produce less than 100 kW, while their larger cousins tower hundreds of feet over the horizon, capable of generating more than 3.5 MW of power.
The U.S. Department of Energy (DOE)’s Office of Energy Efficiency and Renewable Energy provides a step-by-step look at how wind turbines tap potential energy at www.eere.energy.gov/windandhydro/wind_how.html.
Challenges
Wind doesn’t blow everywhere, and rarely does so around the clock. Even in areas with strong wind resources, an active wind turbine typically only generates 20–30% of its “capacity factor”—the total electricity it could generate operating around the clock.
Because it’s temperamental, wind can’t be relied on as a steady source of energy. Instead, think of wind as a “fuel displacer,” allowing baseload power plants that rely on fossil fuels like coal and natural gas to burn less when wind blows.
Moving energy from a wind farm to homes also raises challenges. Transmission infrastructure may not be available in areas where the wind blows best, and building new transmission lines takes time, money, and a lengthy governmental approval process. Before turbines go up, studies must be done to judge the wind’s variability in a given area. And although the sight of a tall, white wind tower may not be as intrusive as other types of power plants, environmental and economic impacts must be assessed.
Although great strides have been made in recent years and more wind turbines are built daily, making wind work as a reliable, affordable energy source will take time. To learn more about wind power’s potential, visit the American Wind Energy Association at www.awea.org or NREL’s wind section, www.nrel.gov/wind.
Sources: U.S. Department of Energy, American Wind Energy Association, National Renewable Energy Laboratory