mrniceguy wrote:
My aim isn't to become completely dependant on the wind turbine for all our electricty
Even when the wind does not blow?
I have the wind data from Manchester and London. As they are quite similar, I guess it would be fair to assume Nottingham would be in between. Roughly 50% of the time, the windspeed is <5 m/s and only 3-5% of the time is it >10 m/s, at 50 m over ground level in open terrain. In between, the time percentage drops rapidly from 5 (14%) to 10 (2%) m/s.
This would pose some practical problems. Commercial turbines give full output at ~16-20 m/s, shutting down at >22-25 m/s. At 10 m/s, the o/p is typically 30 - 40% and at 5 m/s 5 - 15%.
As you are in a region of relatively low wind average wind velocity, you have a choice: the blades are designed to work efficiently at either, say, 5 m/s or 20 m/s. In the former case, it will blow itself to bits come the first gale, even if you feather the blades or, in the latter case, you will have to be content with an average of <20% efficiency, in which case you will need to make it 5-10 times bigger than you think.
Even in Manchester, the wind velocity is at 0 for 5% of the time, usually during the long anticyclone period averaging between mid-November and mid-December, lasting 5 to 10 days, although there are other typical (occurring for over 40% of the years) anticyclones, notably mid-May to mid-June and in September.
Please remember that you will require planning permission, including calculations of safety factors, and permission from your local electricity supplier if you aim to provide surplus to the grid. The latter will have to include details of phase correction and harmonic distortion before they will grant you the go-ahead. It may be that they will have a list of approved inverters; if so, you will have little choice.
I mention this so that you don't go into it unprepared, only to hit a brick wall. If I were you, I'd firstly rig a recording anemometer at the place you propose installing it, so that you can see what the local wind pattern (speed and direction) is (there may be atypical katabatic winds, for example, or some other orographic vertical velocities due to nearby topography or buildings). From those data, you could better dimension the turbine to your needs. It may help to get the records from the nearest meteo office, but remember that microclimates can play an important role, so, even if the office is fairly close, it will not give you an accurate picture (for the anecdote, I have two distinct microclimates in my 1100 m² garden).
Please excuse me for pointing these potential problems out, but I have the feeling from your posts that you may not have thought these things through. If this is not the case, I apologise. Whatever, good luck; you will probably need it!