In 2002, the American Wind Energy Association (AWEA) plotted a course for small-wind turbines—units with a generating capacity up to 100 kilowatts (kW), but most commonly those in the 3-15 kw range—to supply up to 8% of residential electricity demand by 2020.
A little more than a decade down that road, the wind industry has made impressive strides in affecting public policy to encourage and finance small turbine installations and help offset CO2 emission from traditional coal-fired electricity production.
AWEA’s small wind turbine report for 2010, the latest one issued, counts about 144,000 individual unit installations across the country, a more than tenfold increase since 2001. By the association’s estimates, small wind installations currently displace 161,000 metric tons of carbon dioxide, equal to the emissions from 28,000 cars.
The trade group also achieved its goal of gaining state and federal tax credits and other financial incentives for small-scale installations, namely the 30% tax credit afforded in the Federal Residential Renewable Energy Tax Credit through 2016.
But despite that growth, the energy-producing capacity of small-wind turbines is only about 3.5% of the AWEA’s 50,000 megawatt goal by 2020, despite improvements in energy conversion efficiency and more than double the number of equipment manufacturers and suppliers, albeit just 7 in the U.S. and 13 worldwide.
The biggest hitch to the group’s 2020 goals is cost. Despite more competition and a market hungry for renewables, the installed cost for a 5-15 kW turbine has jumped from $3,500 per kW in 2002 to $5,430 per kW in 2010, without applying tax credits or rebates; AWEA’s goal a decade ago was to get that cost down to about $1,800 per kW or less by 2020. The payback on a current system is about 20 years while the design life of a typical small-wind unit is pegged at only 10 to 12 years.
Another hurdle is compatibility. Optimum conditions for a small wind turbine call for 500 feet of clear space around the unit, average annual wind speeds over 12 mph, local electricity rates over 10 cents/kWh, a local utility that will net-meter the production, and a tower as tall as local zoning rules will allow. Imagine suburban and rural lots of more than a half acre.
In its 2020 roadmap, AWEA calculated that 15 million homes could realistically meet that criteria, enabling the industry to achieve its capacity goals. A decade in, they are less than 10% of the way there.
If you’re curious if you build in areas that might be optimum for small-scale wind energy, check out a resource map from the Department of Energy that shows a swath of optimum conditions from the Dakotas to North Texas. Meanwhile, a table produced by the National Climate Data Center shows average annual wind speeds for hundreds of cities.