Wind energy has been used since ages to power wind mills or for pumping water from the flooded fields of Netherlands. Today wind energy delivers more than half of the energy produced by renewables worldwide and it is still one of the cheapest ways to produce energy “out of thin air”.
A modern large scale turbine (rated power around 3MW) can go up to 150m height and can have blades that are over 75m in length. These turbines could produce enough energy for an entire village and they cost millions of Euros.
But if you live in an area where the wind is always messing up your hair, maybe it would be good to install a small wind turbine. They are used mainly for small installations and can have a rated power between 300 W and 50 kV. The majority of small turbines are horizontal axis turbines but vertical axis turbines are a growing type in the market. The rotor diameter of a small machine can range from 2 m to 8 m. In terms of cost, a new turbine will range between 5000 and 20000 Euros, while a second hand one can go below 2000 Euros. When purchasing a second hand turbine make sure you ask for at least 1 year warranty and check all the mechanical and electrical systems before you make the purchase. Look for damage on the blades, tower and wires especially and take care about the claims made in the manufacturer’s brochures as the annual production is usually overstated.
Turbines are usually mounted on towers in order to raise them above any obstacles. It is recommended that the turbine is raised with at least 9 m above the highest obstacle on a 200 m radius. So if you have a 10 m high house you should consider mounting your wind generator at 20 m above the ground. The effect of nearby obstacles needs to be taken into consideration not only for performance reasons but also for safety reasons because turbulence and vibration caused by the nearest obstacles can cause system failure.
Installation on rooftops can be taken into consideration but a strength analysis of the roof structure and the building structure needs to be made in order to ensure safe operation. Rooftop systems in cities rarely produce enough electricity.
In order to produce electricity even in high winds a dynamic braking system that regulates the speed by dumping excess energy is used. The dynamic braking resistor may be installed inside the building to provide heat (during high winds when more heat is lost by the building).
When choosing a location for a small wind turbine, additional to the wind data which tells you how much energy this turbine will produce on your site, you also need to align with the safety distances from roads and other building specified in the country or local regulations.
And keep in mind that wind turbines can be noisy so do not place them near your home or your neighbours home.
A small wind turbine can make you some extra money if you connect it to the grid or it could cover your home energy needs when connected to batteries.
Please let me know your thoughts about the topic. Your comments are always welcomed.
With best regards,