For consumers wanting to generate their own green power, installing a small wind turbine may be an option. Small wind turbines are electric generators that use the energy of the wind to produce clean, emissions-free power for individual homes, farms, and small businesses. With this simple and increasingly popular technology, individuals can generate their own power and cut their energy bills while helping to protect the environment. Unlike utility-scale turbines, small turbines can be suitable for use on properties as small as one acre of land in most areas of the country.
Installing a Wind Turbine
The basic steps for installing a small wind turbine on your property are:
Determine whether the wind resource in your area makes a small wind system economical.
Determine your household electricity needs by checking your monthly or yearly electricity usage.
Find out whether local zoning ordinances allow wind turbine installations.
Purchase and install a wind turbine sized to the needs of your household. The Small Wind Certification Council maintains a list of certified small wind turbines.
Questions to Ask Equipment Manufacturers
What is the energy output (measured in kilowatt-hours or kWh - not in kilowatts or kW) of the turbine, over one year, in average wind speeds of 8 to 14 mph? Is this calculated using real-life ("field") data (preferred), or laboratory / wind tunnel testing?
Can you refer me to other customers who have owned [Model X] for a period of time? (The longer, the better.)
What is the warranty length and coverage? (The industry standard is five years.)
Has the turbine/tower ever gone through a reliability test? By whom? For how long? What were the results?
How long has the company been producing turbines?
How long has [Model X] turbine been available for sale to customers (not in the prototype or beta testing phase)?
For how long was the prototype tested? By whom? In the field or in a laboratory?
How many turbines of [Model X] have been sold, and for how many years? How many of these are still running?
How frequently has [Model X] been re-designed? What were those changes and how recent were they?
What problems have other customers encountered and how have you dealt with them?
Answers to Common Questions
What size turbine is needed to power an entire home?
On average, a typical American home would require a small turbine with a 5-kW generating capacity to meet all its electricity needs. A turbine of this size has a diameter of approximately 18 feet. The exact size needed to power a home, however, can range from 2 kW to 10 kW (12- to 25-foot diameter) based on a home’s energy use, average wind speeds, and the turbine’s height above ground (which affects its productivity).
How tall are they?
The average height of a small wind turbine (of any capacity) is about 80 feet, about twice the height of a neighborhood telephone pole, with a range of 30 to 140 feet. Generator size and tower height are not generally related; a 5-kW turbine could be on a tower anywhere from 30 to 140 feet high.
What is the average payback period?
The length of the payback period depends on the turbine, the quality of wind at the installation site, prevailing electricity rates, and available financing and incentives. Depending on these and other factors, the time it takes to fully recover the cost of a small wind turbine can take anywhere from 6 to 30 years.
How much do they cost?
The purchase and installation of a system large enough to power an entire home costs, on average, $30,000, but the price can range from $10,000 to $70,000 depending on system size, height, and installation expenses. The purchase and installation of very small (<1-kW) off-grid turbines generally cost $4,000 to $9,000, and a 100-kW turbine can cost $350,000. The federal government and many states have rebate and tax credit programs to encourage investment in small wind. In addition, United Wind now offers a wind turbine leasing program.
What happens when the wind doesn’t blow?
For grid-connected systems, the user will not notice a difference when the wind doesn't blow. The utility provides electricity when the wind does not blow, and any extra electricity the turbine generates is sent back to the utility system to be used by a neighbor. Off-grid turbines store power in batteries for on-demand use and are often complemented by solar electric panels to provide more consistent generation.
Do I need to take wind measurements?
Taking detailed measurements to gauge your wind resource is often unnecessary. Experienced installers/dealers or manufacturers can determine whether your property is suitable for a system by inspecting the surrounding area.
How much land and wind are required?
Installers recommend sites with average wind speeds of at least 12 mph, but specific land requirements vary. Zoning codes sometimes impose a minimum requirement on lot size or on the distance a turbine may be placed from a property line and may vary depending on the height of the proposed turbine. Also, it is essential to have a site with unobstructed access to winds, which most often requires higher towers, larger land lots, and non-urban locations. Currently, less than 1% of all small wind turbines are used in urban applications, partly due to zoning restrictions but mostly because wind quality is much poorer in densely built environments. Contact your turbine factory dealer for help navigating the permitting process.
How does the rated capacity of a small wind system compare to its actual performance?
Rated capacity indicates the electric power (kilowatts) at a given wind speed, so the answer depends on wind speed and the turbine. A more accurate indicator of energy production, however, is swept area. A 5-kW turbine (average residential size, 18-foot rotor diameter) produces around 8,000 kWh per year in 12-mph average winds, which is about 100% of what an average U.S. home requires. At the larger end of the spectrum, a 100-kW turbine (60-foot diameter) in these conditions will generate around 200,000 kWh per year.
Are batteries or other storage needed?
There are two types of systems: those connected to the electricity grid (“on-grid”) and those used off-grid (for battery charging) or backup power. Many systems sold today are off-grid, but demand is rising for on-grid systems that essentially use the grid as a battery: When the wind blows, the owner uses electricity from the turbine; when winds are low and consumption is high, the owner uses electricity from the grid. The smallest wind turbines are used in conjunction with solar photovoltaic technology.
How are small wind systems maintained?
Routine inspections should be performed once a year of a turbine’s 20+-year lifespan. A professional installer or trained technician (usually the manufacturer or dealer that sold the turbine) maintains the turbine and tower through physical inspections, though some turbines can be monitored remotely from a home computer.
Source: American Wind Energy Association
Grants and Incentives for Small Wind Energy Systems
As of March 2009, the federal government offers a Residential Renewable Energy Tax Credit for the purchase and installation of qualifying small wind electric systems, worth 30% of the value of the system.
Established by the Energy Policy Act of 2005, the federal tax credit for residential energy property initially applied to solar-electric systems, solar water heating systems, and fuel cells. The Energy Improvement and Extension Act of 2008 (H.R. 1424) extended the tax credit to small wind energy systems and geothermal heat pumps, effective January 1, 2008. Other key revisions included an eight-year extension of the credit to December 31, 2016; the ability to take the credit against the alternative minimum tax; and the removal of the $2,000 credit limit for solar-electric systems beginning in 2009. The credit was further enhanced in February 2009 by The American Recovery and Reinvestment Act of 2009 (H.R. 1: Div. B, Sec. 1122, p. 46), which removed the maximum credit amount for all eligible technologies (except fuel cells) placed in service after 2008.
A taxpayer may claim a credit of 30% of qualified expenditures for a system that serves a dwelling unit located in the United States and used as a residence by the taxpayer. Expenditures with respect to the equipment are treated as made when the installation is completed. If the installation is at a new home, the "placed in service" date is the date of occupancy by the homeowner. Expenditures include labor costs for on-site preparation, assembly or original system installation, and for piping or wiring to interconnect a system to the home. If the federal tax credit exceeds tax liability, the excess amount may be carried forward to the succeeding taxable year. The excess credit may be carried forward until 2016, but it is unclear whether the unused tax credit can be carried forward after then. The maximum allowable credit, equipment requirements and other details vary by technology, as outlined below.
See the Renewable Energy Tax Credit page in the Database of State Incentives for Renewables and Efficiency website for more details.
Home Power. Wind Power
Montana State University Extension. Small Wind Overview
RENEW Wisconsin. Small Wind Toolbox
U.S. Department of Energy. Small Wind Guidebook
Windustry. Home and Farm-Scale Wind