Harnessing the Wind to Power Your Home

Home wind Turbines to save Electricity Wind energy on a large scale is now competitive with other sources of electricity on the national grid. However, small domestic-sized wind turbines have not yet reached this point. The wind is free, but small wind turbines are expensive in relation to what they produce, and cannot realistically compete with mains electricity. If it were easy to save money by using small wind turbines, then they would be a major feature of the landscape by now.

Wind Turbines need wind, and lost of it, to produce even a small amount of electricity. Most people think they live in a windy place, but in fact most residential locations are not suitable for windpower. Trees and buildings break the force of the wind, and create turbulent gusts which can be very destructive. Open hilltop sites or coastal situations with unobstructed views may be suitable for siting a wind turbine.

Wind turbines work with thin air, so they need to be large in relation to the power they produce. To power a modern home on a good site, the blades would need to span about 5 metres from tip to tip. This is known as the rotor diameter. With careful conservation of energy a smaller machine may suffice. A rotor diameter of 2 metres might yield about 500 kWh of electricity per year, compared with an average annual household consumption of roughly 4,500 kWh.

Most small wind turbines are used for charging batteries, to provide a reliable stand-alone power source where grid power is not available. The obvious choice of generator for self-build is the car alternator. However this has major drawbacks. In low windspeeds there is very little power available in the wind, and you need a highly efficient generator to capture it. Most, if not all of the power in light winds will be used up energising the magnetic field in the alternator, so the results are disappointing. Nearly all small commercial wind turbines use purpose-built permanent magnet generators for this reason.

Safety is an important issue even with the smallest wind turbines. Never underestimate the destructive power of a runaway windmill rotor in a high wind. Control systems are as important as any other part of the wind turbine. On top of this, wind turbines mounted on a chimney stack have also been known to weaken the chimney, causing it to disintegrate or even collapse catastrophically.

In conclusion, if you live in the Mournes, the Sperrins or on the Antrim Plateau you probably have a good chance with producing some power with wind turbines. The key to embarking on a turbine project is not to overestimate the electricity it will produce or the money you will save!

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