As more homeowners are searching for ways to reduce their carbon footprints, increasingly people are looking to home energy generation. While the most popular energy saving system to date is passive thermal heating of hot water, solar photovoltaic systems are also growing in popularity. Wind turbines are another, often overlooked, but extremely effective system of home energy production, however they do require a little more research and a lot more attention to the right design for your home.
Home wind turbines are state-of-the-art, aerodynamically designed small electrical generators powered by air-flow. The wind turbine rated power output start at around 500 watts but more effective for home use are the wind turbines rated anywhere from 1, 2, 3, 5 to 10 or more kilowatts. Dependent upon your power needs, where your home is located and perhaps most importantly – how windy it is where you live - there is likely to be a home wind turbine that will meet your energy generation needs.
Location, location, location
The best spot to locate a wind turbine is on a hill near the ocean, barren mountaintops or a few kilometers out at sea. Since none of these may be available to the average homeowner then an open pasture, roughly an acre in size, or a sparsely populated semi-rural area, would be a good second choice.
Based on current technology, homes in urban centers aren’t optimum for most wind turbines because of the turbulent wind flow around surrounding buildings. Ideally, the wind turbine needs to receive reasonably strong, non-turbulent airflow to get up to speed and maintain a healthy rotational velocity. The urban areas that could best use wind turbines effectively are the roofs of high-rise commercial and residential apartment buildings.
You could mount a small wind turbine on the roof of your home, but it is unlikely to generate much energy. A better alternative is to mount it on a tower that the turbine seller can also provide. These towers should be 10metres (or more) high. Prior to purchase or installation, check local bylaws to see if there are any height restrictions or specific anti-wind turbine regulations.
Drawbacks
Many people think wind turbines generate a lot of noise, are a blight on the landscape and that they kill birds and bats. Some of these concerns are true for the large 2.5mega-watt wind turbine but the homegrown variety are much more benign. However, some individuals do have sensitivity to the ‘vibration’ generated by the wind turbine and it is important to visit a few sites with smaller wind turbines before making a decision to purchase one.
Cost
Wind turbines are not cheap. However, many countries are offering grants as incentives to switch to alternative energy. A 1 to 10kilowatts wind turbine will range in price from $2,000 to $18,000. You will also need to purchase batteries to store the electrical energy for use when the wind is not blowing, or if your home is completely off-grid. Another option is to sell your excess electricity directly to the your local utility company rather than store it in batteries at your home.
Inverters and rectifiers, plus other controllers, will also be needed to handle the electrical energy from the wind turbine. Towers, batteries and other electronic items can easily double the cost of wind turbine power though government grants are increasing. The US government recently announced they would provide a $4000 tax incentive for the installation of small wind turbines. The UK has similar programs for renewable energy generation.
Output
They may be pricey but when a wind turbine is placed in the right location and has a reasonable average yearly wind velocity (generally above 3.5ms-1 or 12.6kph/7.9mph), they can really generate a lot of electrical energy. There are many wind turbine suppliers around the world. The Dutch, British, American and Chinese are all making smaller wind turbines for the home. Most wind turbines come with a long warranty and with the correct maintenance can last up to 20 years. The batteries and electronics will need replacing in roughly half that time.
Installing a home wind turbine may initially be expensive for the power they generate, but achieving energy independence may well be worth the price.
Resources
Canadian Wind Energy Association: www.canwea.ca
American Wind Energy Association: www.awea.org
European Wind Energy Association: www.ewea.org
Trevor Williams is a University of Victoria Mechanical Engineering PhD candidate specialising in renewable energy, power grid modelling and plug-in hybrid electric vehicles. He has a bachelors in Aeronautical Engineering, a Masters in Management Science and over 23 years international experience in the space industry, having worked on Earth observation and telecommunications satellites.
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