Micro Wind Turbines are similar in principal to the large white turbines that grace or blot our landscape depending on your point of view. The larger turbines used in Windfarms are directly connected to the grid at the Medium Voltage (MV) level normally 11kV or 33kV. In a large turbine the power is converted real time into grid compatible 50Hz. While this conversion is expensive both in terms of low efficiency and initial capital cost these turbines are typically sited and maintained for 10-20 years to recoup the outlay.
At the domestic end of the market there are two main types of system, direct and storage: storage is further divided into on and off-grid systems.
Off Grid
Off-grid systems normally entail micro or mini turbines in conjuction with other forms of renewables including solar panels and non-renewables like diesel generators. The many different energy sources are usually combined into a battery bank with a stand alone inverter. The inverter supplies the 230V mains electricity we normally associate with the mains.
The benefits of this system are that it is that it can be made fault tolerant ie if one component fails chances are you still have some power, and that it is comparatively easy to design and add to later. The drawbacks are largely cost and maintenance; both diesel generators and batteries require at least a bi-annual checkup.
Grid Connected
A simpler and more elegant technique would be to take the "wild" power generated by the wind and directly convert it into mains compatible with the 230V 50Hz present in your household wiring. Low cost modern electronics and highly developed inverter designs have now made this possible.
Many people unfamiliar with this approach worry about "leakage" back into the grid, or fail to understand the grids ability to accept power generation as well as use.
Effectively a grid connect wind turbine makes you a very small power station, if you had no loads turned on in your house the power would flow back into the grid and give power to your neighbours. What is far more likely is that your typical standing load of fridges and power electronics will use the power you generate and what you will see is a reduction of the electricity bill.
The main benefit of this system is its ease of connection, it could concievably be plugged in like any other appliance as Windsave are campaigning for.
