Sunday, December 03, 2006

The winds of change

I visited our local B&Q recently to get a new light switch after one of ours went a bit flaky. When there, I noticed that they are now selling domestic turbines which can be fully fitted for £1,495 including VAT. I took home a leaflet and thought about the economics of doing such a thing. It generates 1kW worth of power whilst the wind is blowing and from this article it can produce up to 2,000 kW/hours of electricity a year. As there are 8,760 hours a year then this suggests a usable wind about 25% of the time. (The rest oof the time, there is insufficient wind or too much and the unit goes into bypass).

As a Kilowatt/hour costs me approximately 10p then I can save a potential £200 a year with a wind turbine and the payback is under 8 years. The safe design life of the device is 10 years, so superficially, it seems viable. However, I strongly suspect that there will be an annual safety inspecion required after year three (at least £40?) and unless electric prices spiral upwards out of control then economics can't justify a purchase. Of course, it doesn't generate any carbon dioxide but what was the environmental cost of manufacture I wonder? The planning application costs certainly tip it over the edge.

There is also the issue of fitting a 1.7m wind turbine onto a modern quasi-semi in a fairly densely packed housing estate. Is the thing going to wail like a banshee and transfer groans and rattles through the brickwork?

It seems that there are 30% grants available that might make it notionally cost-effective, but spending someone else's money doesn't make sense with market forces, the viability still remains suspect.

I await the first turbine application to Morley Town Council Planning Committee with interest!


Serf said...

You failed to include the time value of money. If you borrowed that £1,495 at a rate of 5%, then you would need to pay around £200 per year to repay it. So it just about breaks even.

It is still at the level of a gimmick, and prices need to come down significantly to make it a real option.

Ian Grey said...

I was going to do an NPV (Net Present Value) calculation where it is assumed that you have the money already but don't spend it and use it to get interest, a figure that also dints the business case.

However, we are simple Yorkshire folk here in my regular audience!

As an aside, the Windsave WS1000 Plug 'n Save (tm) is actually £1,498 so there is another three quid to find...