EcoHearth: Come Home to the Earth

Like most renewable energy measures, home wind power is an attractive option for reducing both your energy bills and your carbon footprint. There are many good reasons to install a home wind generator (also called a wind turbine or windmill), but it may not be cost-effective or feasible in every situation. A few considerations can help you determine if it is right for you.

What
Wind power is an indirect form of solar energy. The sun heats land, water and air at different rates, causing wind to blow. Since at least the 10th century, people have harnessed wind energy with rotors. Initially, they used windmill rotation directly to drive water pumps and grain grinders. Modern wind generators convert the rotational energy into electricity via electric alternators; this electricity then powers appliances that do the work.

In a simple home system, rotating blades spin magnets to create voltage. The system converts the voltage into steady alternating-current electricity that feeds into the home wiring and also may be stored in optional batteries. It is then used just like other electricity in the home.

Why
US electric utilities still run mainly on coal, so even small measures to decrease electric-grid output limit fossil-fuel consumption, diminish pollution and reduce global warming. Like solar panels, wind turbines do not generate power 24 hours a day. Without blowing wind, they cannot generate electricity. Fortunately, batteries can store the excess energy from windy times for use later.

Alone or in combination, solar-photovoltaic panels and wind turbines can power a small off-grid house. Most wind-power systems are tied to the electric grid. When a strong wind is blowing, the turbines power the house and feed any surplus energy into the electric grid (which should show up as credits on a home power bill). Conversely, when wind is not blowing, and there is nothing more stored in batteries, power can be consumed from the grid.

Where
Wind is a fickle friend. It can blow at hurricane strength for days, then not muster a breeze for weeks. Either extreme might make a wind generator a poor investment. Some areas may be too calm for a wind generator to produce sufficient electricity, and extremely fast winds can break rotor blades or burn out the alternator. Consistent, moderate wind is the ideal for a home wind-power system.

The National Climatic Data Center lists average year-round wind speeds in cities throughout the United States. (Interestingly, Chicago—the Windy City—falls below Dodge City, KS; Amarillo, TX; and Rochester, MN on the national list for strong, consistent wind.) Wind turbines aren’t very effective in cities with average wind speeds below 10 mph. Above the minimum, doubling wind strength increases wind-power generation by a factor of eight.

Other home-specific considerations include siting, acreage and legal restrictions. Even in Rochester, turbines blocked by large trees in a wind-protected valley will not generate much wind power. Wind-power turbines need unobstructed air at the height of the rotors and in the direction of prevailing winds.

How
Home wind power typically makes the most sense in rural areas with plenty of unblocked wind, higher electric-transmission costs and no nearby neighbors to complain about a big (and to some, unsightly) windmill on the property.

Most experts recommend placing turbines in the yard, rather than on the roof. Roofs make wind weaker and more turbulent, and turbine vibrations can be felt in the house. Cities also typically require a zoning permit before a home wind turbine can be installed, and may impose height restrictions. Some homeowner-association rules forbid home wind turbines entirely. Installers usually can answer homeowners’ other questions on the placement and feasibility of home wind-power systems.

How Much
According to the American Wind Energy Association, an installed wind-power system large enough for an average home costs $40,000 before rebates and incentives. The US Department of Energy has an up-to-date database of renewable energy-incentive programs. The AWEA, an industry trade group, lists certified and recommended turbine manufacturers.

If wind power is not feasible, a homeowner or renter can still indirectly harness wind energy by purchasing wind-power credits. At least 750 utilities offer green-pricing programs, allowing users to pay a premium on their power bills to offset the costs of building new wind farms or expanding other renewable energy systems. The US Department of Energy lists green-pricing programs around the country.

If you live in an area with optimum wind speeds and frequency, installing a wind turbine may be right for you. Just be sure to comply with any local restrictions and you’ll be well on your way to saving money while lessening your impact on the Earth.

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