Tuesday, October 20, 2009

Planning for wind

This is a 6kW Proven turbine on a 15m mast, courtesy of Proven. The little girl is not one of my grandchildren!

I have just written to our local planning officer to find out how the land lies for a full planning application for our intended Proven 6kW turbine.

Why a wind turbine? As you may have read in earlier posts, we propose to install a small wind turbine on our farm in Llangybi, north west Wales. We have two reasons for wanting to undertake this project: firstly we feel we have to do what we can to help combat climate change and are already doing what we can. We have grandchildren and are concerned about the world they will inherit. In this windy area, a turbine is easily the most practical way for us to more than neutralise our carbon footprints. As we approach the critical United Nations Climate Change Conference in Copenhagen, our own government exhorts us all to take action (Act On CO2). This we want to do. Secondly, the turbine should generate a useful income (particularly with Feed In Tariffs) and thus become an additional diversification for our main farm business of growing vegetables in a co-operative for our local box scheme. Details of this environmentally friendly scheme are available on the Llangybi Organics website.

The Site: This is to be in the centre of our land, as far from neighbours as possible whilst consistent with being appropriate for turbine location. You can also view the site on a Google map (a pin marks the spot and the high-resolution satellite imagery shows the hedgerows clearly ).

Windspeed data: A viable average windspeed for microgeneration is generally taken as 5m/sec. How do we best know what our average windspeed actually is?

  • NOABL (BIS) database gives 5.3 - 5.6m/sec for 10m above ground level (agl) (grid squares SH4341 and 4241 in which the turbine will actually be located) and 6.1 - 6.3m/sec at 25m agl. Turbine hub height of 15m agl should receive an average of 5.7 - 5.8m/sec.
  • Carbon Trust Wind Yield Estimation Tool gives 6.0m/sec at 15m hub height with anticipated 13,885 kWh/y generation potential with corresponding CO2 saving of 7.456 tonnes/y
  • Anemometry from October 2008-October 2009 on exactly the planned site with anemometer 11m agl has given average wind (in a year with long periods of blocking anticyclones) at 5.1m/sec based on 147,331 data points. For a description of this, see my previous post. [By the way, this complete set of equipment is now for sale so if you're interested, let me know by way of a comment with your email address. This includes the data logger base station, anemometer and everything needed to connect to a PC including software and cables, the 11.5m mast and supporting gear. I have even calibrated the anemometer. About 100 pounds for the lot!]

Distance from neighbours

Cae Du (upwind for the prevailing southwesterlies) c.160m
Llwyn Helyg (downwind) c.200m
Brongybi (to west) completely shielded by intervening woodland

Turbine details: Proven 6kW on 15m mast (high enough to avoid turbulence from hedgerows and a serious reduction in performance). The installation will be about 60m from our house where it will be connected to the grid via an inverter. Its slow rotation speed and direct drive (no gearbox) means that this turbine is both reliable and the quietest on the market in its class (e.g. 45dBA at 5m/sec). The result is that noise from the turbine is reduced to the swish of the blades turning in the wind, virtually unnoticeable compared with

background sound. See and hear examples from our intended installer's website. And yes, we have been and stood underneath these turbines and they really don't make much noise. The more the wind blows, the more noise there is from the wind in the trees and hedges which tends to drown out the increased whooshing of the turbine.

We await the planner's views before we pay something like 300 pounds just to ask for permission. In this day and age, you'd think every small farm like ours would be encouraged by government to put up turbines. It may come as permitted development rules change and the urgency for tackling climate change finally sinks in.