The wind turbines generate power by rotating a permanent magnet generator inside of them which generates single or three phase AC at the frequency of the turbine's rotation.Grid Connection
The AC power from the generator is not only the wrong voltage to be connected to the national grid, but also, as the wind speed changes so does the rotational speed of the turbine, and therefore the frequency of the power generated. The power from the generator therefore needs to be converted to DC and then fed into a special electronic device called an inverter, to ensure that it is always at 240VAC and 50hz, as required by the UK’s grid system.
Any power you generate will be first used by your own property, thereby saving you the maximum amount possible on your electricity bill. Any excess energy your wind turbine generates, e.g. on windy days or at night, is "spilled" to the National Grid and your electricity supplier pays you for it.
In order to charge your electricity supplier for any energy that you export to the grid, you need to have a new bi-directional electricity meter installed which will work both when you buy (import) and sell (export) electricity. To claim your sale of Renewable Obligation Certificates (ROCs) you will also need a ROC meter, which keeps track of all the energy your turbine generates, irrespective of it being used by you, or exported to the grid. You can find more information on our Selling Your Power information page.
Shown below is a simplified block diagram of how all the system components are connected.
The inverter also provides essential safety features to control the power output from the turbine, and to automatically switch off the current if the grid connection should fail. This means that should the grid connection fail, the inverters will switch off their output and there is therefore no danger to any maintenance engineers fixing the fault. This does however mean that the wind turbine will produce no power to the property if the mains connection fails.Further Information
Segen however shortly hopes to offer an off-grid package which when combined with a battery pack, and optionally solar PV panels and/or a diesel generator will enable the generation of “mains” power where there is no grid connection.
Grid Connection Application
For all single phase grid connected turbines, which have a rated power of more than 3.6kW, Segen needs to apply to the local electricity supply company for permission to connect your turbine to the grid. This also applies to multi-phase installations where the maximum power per phase exceeds 3.6kW.
Segen will make the application on your behalf and will deal with any initial enquiries that are raised by the electricity supply company.
If order to do this Segen will need your Meter Point Administration Number (MPAN) from a recent electricity bill. Please read our short MPAN Guide on how to find this.
Customers in the area covered by Norweb (United Utilities), who wish to make a single phase connection, unfortunately have to pay a £200 + V.A.T. (£235) "administration fee" to United Utilities for this service, and subject to what their investigations find they may insist upon a higher cost grid connection.
Other companies do not make a charge to process the application, but if any changes are required to your grid connection, they will make also make a charge for that.
There is a very detailed 97 page Technical Guide to Connection of Generation to the Distribution Network, produced by the DTI and published by the Energy Networks Association. You should only open this however if you really want to get into the details, as Segen and the electricity supply company will deal with all this on your behalf.