
Make your own electricity! A great idea, especially when you look at your latest bill. Perhaps you can even feed it back to the grid, making them pay for electricity you produce. The People strikes back. It is also eco-friendly. Well, is it?
Micro generators fitted to a roof or wall mounted on private houses have found some buyers over the last few years, partially due to subsidies through the UK government’s Low Carbon Building Programme, and then some more in 2006 when DIY-chain B&Q launched a campaign, selling the Windsave 1000 (a 1kw mini wind turbine) for £1500. It was a package and included installation, feeding the electricity straight into the building’s standard ring mains supply for 230 Volt. Plug-and-play, the way we like it today. Since no batteries were involved it was a matter of use it or lose it, the electricity generated. These types of units are referred to as SWTGS (Small Wind Turbine Generator system). The idea of having your own SWTGS with a SSEG (Small Scale Embedded Generator) does sound sweet.
The trouble with this model -and many of its competitors- is that there is so much, well for want of a better word, trouble. It especially when they are put up in an urban setting. They are, first of all, not reaching the amounts of electricity that they claimed to produce. One example comes from Donnachadh McCarthy, famous for having the greenest home in England. He calculated that in its first 3 months, his turbine had powered one energy-saving bulb for around three hours a day and had created a total of 1.6 kWh. This equals more or less 20p worth of electricity. In three months. At that rate, for the Windsave 1000 to cover its 2006 sales price, it would take one thousand eight hundred years. Which means that there are only 1797 to go? The internet, on blogs and forums, is littered with similar stories. On the one hand the manufacturers claiming that it will cut your electricity bill by 30% which almost certainly it will not unless you live on a hill or in the middle of a large field with consistent, strong winds for it to produce 1000kWh per annum.
The Windsave 1000 nominally generates 1kW at 12 metres per second wind (27mph), and starts generating power as soon as the wind is over 4 metres per second. Turbulent wind and lower wind speeds result in far lower power outputs.
For it to produce enough energy to become carbon neutral, or whichever criteria fits best, it is probably not thousands of years but far of the map all the same. Small horizontally orientated wind powered generators in urban areas forced to use erratic winds simply does not work. Under these circumstances it will spend most of the time chasing the wind, not harnessing it.
We will be presenting different models in our new Eco Build directory. In the right conditions, the right wind turbine does a good job.
Posted under Eco Build, Gas & Electricity, Product Innovations, Renewable Energy
This post was written by Leif Ahnland on January 21, 2009
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