Monday, September 15, 2008
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...