A wind turbine is an Alternative Energy Device (AED) that converts kinetic energy from the wind into mechanical energy, which is then converted into electricity.
Wind turbines for residential use have been available for decades. Residential wind is considered a mature technology and with the many improvements over the years, has become more reliable.
ODOE requirements for Residential Wind Systems
- The wind Alternative Energy Device (AED) must have a minimum tower height of 70 feet.
- The wind Alternative Energy Device (AED) must meet or exceed the AWEA 9.1 standards.
- The wind AED site must have a minimum annual average wind speed of at least 10 mph at hub height. 1
- All portions of the wind AED’s rotor disc must be at least 30 feet over any object within a 400 radius of the tower’s base. 1 2
- The wind AED must produce at least 100 kWh per month or 1,200 kWh over the course of a year to be eligible for a residential energy tax credit. 1
- The incentive has switched to an “actual production” based incentive, instead of an estimate of production. 3 4
Other requirements may exist, please see Oregon's Administrative Rules
(A taller tower may be needed to achieve this requirement). 2
(Tree growth over the next 20 – 30 years should be considered when siting the wind AED). 3
(To ensure that you are able to take full advantage of the tax credit, make sure that you have the proper wind resource at your location and that the wind AED is properly sited). 4
(You will be required to submit at least six months of “actual production” data from the wind AED in your application. Make sure to track the monthly production totals from the production meter).
Choosing the right size residential turbine
Wind turbines for residential applications typically range from 2,500 watts (2.5kw) to 10,000 watts (10kw). There are, however, larger residential wind turbines available. Typically, a rotor for a residential wind turbine will range from 12 to 42 feet in diameter.
For example, a wind turbine with a 5 kilowatt generator that is installed at a site with a 12 mile/hour annual average wind speed at hub height will generate about 9,400 kilowatt hours annually or an average of 780 kWh a month. However if the average annual wind speed at hub height is only 10 mile/hour it may only produce about 6,600 kWh annually or 550 kWh monthly.
If the home’s annual electricity needs are less than the annual output of the wind turbine, a homeowner can consider reducing the tower height to the minimum acceptable tower height of 70 feet (providing the entire rotor disc will be at least 30 feet above all obstacles within 400 feet of the wind turbines base). Or, purchase a smaller wind turbine. If the annual energy needs are higher, then a homeowner could consider using a taller tower or even consider purchasing a larger turbine to meet their annual electricity needs.
Hope does not turn the blades
Not all residential wind turbine projects are successful. When homeowners do not understand the technology, they are inclined to use an undersized wind turbine and place it on a short tower, in an area with little or no wind resource. As a result, the homeowner ends up with an inadequate energy resource.
Wind turbines need constant and steady wind to produce electricity. When determining a location for a turbine, the area will need to have a minimum of a 10 mile/hour annual average wind speed at hub height for wind power to be a viable residential solution. The 10 mile/hour wind speed is the bare minimum wind resource that should be considered for wind alternative energy devices. The higher the wind speed is at hub height, the more electricity can be produced.
Selecting the proper tower height for a wind turbine
A wind turbine’s tower can range from 70 to 180 feet in height. Wind turbines are placed high above the ground so that all portions of the rotor disc are at least
30 feet above any obstructions within a 400 feet radius of the wind turbine’s base. Obstructions around a wind turbine such as buildings and trees are known to reduce wind speeds and cause turbulence. Properly sited wind turbines should experience reduced turbulent airflow. Turbulent airflow can reduce a wind turbine’s overall performance and lifespan. Wind speeds usually increase with height. Therefore, using a taller tower can increase the wind speed at hub height and increase production of the wind turbine.
Wind Assessment Reources
Energy Trust of Oregon wind assessment map
AWS truepower wind assessment
3Tier First Look
Please click on the airport nearest your location. Once the site loads you will need to click on “wind rose” to be able to see monthly wind rose and wind speed data for that location.
Ready to begin?
The Energy Trust of Oregon maintains a list of small wind contractors
. They can assist you in qualifying for incentives through the Energy Trust of Oregon if you are a customer of Pacific Power or Portland General Electric. They can also assist you with meeting the qualifications listed above for the tax credit.