Micro-wind turbines for House Hold Use

Photo: Micro power to the people! This small, mast-mounted Rutland Wind charger is designed to trickle-charge 12V and 24V batteries, such as those used in small boats, far from the grid. At a wind speed of 40–55 km/h (20–30 knots), it will produce a handsome 140–240 watts of power. At 20 km/h (10 knots), it produces a rather more modest 27 watts.

If Small is beautiful, micro-wind turbines—tiny power generators of about 50–150 W capacity, can be install on a Roof or mast—should be the most attractive form of renewable energy by far. They're certainly very widely used for all kinds of portable power, typically for recharging batteries in things like yachts and canal boats, and for powering temporary traffic lights and road signs and road lights.

Some manufacturers have pushed micro-wind technology aggressively, hinting that people could make big savings on electricity bills, and benefit the environment, by putting a little turbine on their roof to feed energy into the national power grid. The reality is a bit different: micro-turbines linked to the grid do indeed bring economic and environmental benefits if they're sited in reliably windy areas, but they're less helpful in towns and cities where buildings make "energy harvesting" more of a challenge and there's much more turbulence from obstructions. So are micro-wind turbines really worth the investment? How do they compare with their big brothers?

How micro-wind turbines compare

These figures are simply designed to give a rough comparison of the differences between large-scale and micro-wind turbines. Bear in mind that there's a huge variety of micro-turbines.

	Large	Micro
Mounting	Tower roughly 80–100m (260–344ft) high.	Roof, or mast typically ~10m (30ft) high.
Rotor diameter	Up to 90m (300ft).	1–4m (3–12ft).
Energy production	1–8 megawatts (1000–8000 kilowatts).	50–40,000 watts (0.05–40 kilowatts).
Operates in wind speeds	10–55mph (16–90 km/h).	10–40mph (16–64 km/h).
Cost	$1–2 million per MW.	$500–100,000.
Provides power to	500–5500 homes.	1 home (or single site).

How to set up your own micro-wind turbine

If you want to build your own micro-wind turbine, what do you need? The first thing to bear in mind is that small wind turbines spin at dangerously high speeds, so technical skill and safety are paramount: ideally, get your turbine installed by a professional. Apart from the turbine itself, you also typically need a piece of electrical equipment called an inverter (which converts the direct-current electricity produced by the turbine's generator into alternating current you can use in your home) and appropriate electrical cabling. Your turbine will also need either a connection into the grid supply or batteries to store the energy it produces.

Photo: Although micro-wind turbines on homes have proved controversial, they definitely have their place. Here's the Rutland Wind charger from our top photo helping to charge the batteries in a go-anywhere, portable highway construction sign. It's getting help from the large flat solar panel mounted on top. This is a great example of how micro-wind turbines can be useful if you put them in the right place, at the right time.

Some Important Points Keep  in mind:-

• Before Installation of the windmill first you have to analyze the weather and wind forecast at least 2/3 months to choose a good location.
• The best place to start is with a professional assessment of your site's wind potential, which involves a series of measurements with an anemometer. Remember that wind turbines generally work far better in open, rural areas than mounted on rooftops in cities.
• Don't assume it will automatically be windy enough to make the investment in a microturbine worthwhile: a recent UK study of microturbines by Encraft found a mixed picture, with good performance from the best-located turbines and the very worst performing model (embarrassingly) not even producing enough electricity to power its own electronics—in other words, using more electricity overall than it produced. Some contribution to the environment!
• Depending on where you live, you will almost certainly need planning consent for a wind turbine, so check that out carefully with your local authority first.
• Sound out your neighbors before you start spending any money: instead of turning your "local friends" into bitter enemies with your rooftop propeller, maybe you could persuade them to join you in a community green-energy venture?
• Remember that roof-mounted wind turbines could prove noisy and cause problems with vibration.
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Acknowledgments

For useful comments and suggestions on this article, I'm extremely grateful to all the viewer’s of  Renewable Energy Resources.