Planning for wind

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.

Wind turbine: the start

Beginnings: We've started the lengthy business of investigating the possibility of installing a wind turbine. I'd already homed in on Proven as being the best of the bunch of small wind turbines. The 6kW machine looks like the one we'd opt for, the aim being to provide much of our power and to export the surplus to the grid. The video is of one of the four 6kW Proven turbines which form the backbone of the island of Eigg's grid during a visit in June. Most of the noise is the rumble of the strong wind in the camera's microphone.

Site visit: There are a number of hurdles to leap before any final decision can be made. I requested a visit from Tony Carver of Natural Energy, an approved installer of Proven turbines, who kindly agreed to make a site visit without charge. I showed him the site I thought most likely, within reasonable distance of the house for connection purposes but quite open to the prevailing southwesterly winds, the prevailing wind direction here. He accepted that this was indeed the best option and then erected a 10-metre telescopic 'flag pole' (pictures) with a balloon attached for visibility, just to give an impression of the height of the tower. This wasn't too successful as the day was, ironically, very windy and the thin pole bent like a long fishing rod! Tony and I had both checked the BERR windspeed database for the area. It provides averaged speeds for each kilometre square of the country and so gives a rough idea of what to expect. It suggests a speed of 5 metres per second would be the average at 10 metres above ground level. This is just about enough to make the economics worthwhile. But to be more certain, there's another hurdle to jump before considering the trickiest hurdle of all: planning consent. (I anticipate problems here but hope I might be proven wrong.)

Anemometers away! You can purchase an anemometer kit for just over £100. Tony Carver suggested I should do this and stick the device on a scaffold pole tower for a few months. I have followed up his suggestion and purchased a LaCrosse WS3502 wind station (pictured, in fancy box). This comes with a wireless transmitter and base station. It claims a range of 100 metres so I should be able to pick up the transmissions from the house. It also comes with software to enable all the readings of windspeed and direction to be uploaded to my computer and for averages to be calculated; in short, all I need to find out accurately what the wind speed average at the proposed turbine site actually is. The next stage is to find some way of getting it on a sturdy pole at least 10m high and to that end, I have applied to join the Green Building Forum so I can solicit ideas about how best to do this.
And the economics? Will the outlay be justified? We're looking at a capital cost in excess of £20,ooo. To put it in other terms, that's a lot less than a luxury SUV which is guaranteed to guzzle energy and money. In contrast, this machine -- with a design life of 25 years -- will generate money every time the wind blows above its cut-in speed of around 2.5m/sec. Unlike some turbines, this one doesn't shut down in severe gales. It just carries on generating at its maximum output of 6kW.
When I started thinking about turbines, I did so from the point of view of being green. I no longer see it like that. I'm now interested primarily because the machine can reliably generate money. Which is better? I wondered. Have the money in the bank with inflation going up, stock markets going down and recession looming? Or have the capital asset of a sturdy turbine which could be generating me a thousand or two each year? Add on the rapidly increasing costs of electricity supply, the increasing ROCs (explained here) and the near certainty that even the laggardly 'green' British government will soon have to instigate a feed-in tariff scheme, the cash generation potential of my turbine can only increase. That's what I'd call a good and secure investment... green too!
But it could all come tumbling down at the next two hurdles: wind speed average and planning consent. You'll be hearing from me again...