Wednesday, October 11, 2006

Micro turbines: The jury is out

B&Q sent me an email the other day advertising their new Windsave rooftop turbine.

This is likely to considerably boost penetration of this kind of product. I am a big supporter of wind power, and I think it would be great if everybody had a 1 kW wind turbine on their house, providing most of their electricity needs and recharging their cars.

However, the question remains of whether rooftop locations are suitable for this kind of product. The Centre for Alternative Technology express concerns about turbulence and stresses on the building structure.

If a turbine needs a clean airflow and doesn't get it, it will not generate much power and will wear out quickly, perhaps having a zero or negative life cycle impact on carbon emissions, and obviously failing to deliver an acceptable return on investment.

If it damages the structure of the building, this would have to be repaired at great expense and not insignificant environmental cost.

CAT's advice is quite old - it has been there for a while. Perhaps the latest breed of turbines has overcome these problems. But perhaps it hasn't. These issues don't seem to be addressed in the marketing of new turbines. So this could be a big mis-selling scandal, exacerbated by well meaning promotion by supporters of renewable energy.

Newsnight's ethical man Justin Rowlatt is getting one. I will see how he gets on before considering one for myself.


Edis said...

George Monbiot has come out against micro-turbines, saying that "in almost all circumstances micro wind turbines are a waste of time and money" and that concentration on this approach could wreck our chances of stopping global warming. See New Scientist 30 Sept 2006 P24. Some interesting references that could form part of this debate....

Joe Otten said...

New Scientist hides most of that article as premium, but Monbiot republishes it here.

Monbiot seems to be the sort of person who sees any disagreement with him as resulting from a lack of virtue. Thus supporting micro turbines is not just mistaken, it is 'complacent'.

He paints a particular picture with his figures to support a polemic, and in many cases he will be right. But wind is all about the suitability of the actual location - some people will have good locations. And generating rather less than half your needs can still be valuable. These small 1kW turbines are rated at 12.5 m/s, at a more likely 4-5 m/s they would probably only generate 100W. But 100W is still useful.

So all I'm saying is don't rush into buying the B&Q turbine, and that we could do with some good impartial advice on the suitability of our actual rooftops.

ecofx said...

It would be great to have a few people blogging their logging of generation with micro turbines.

A lot of opinion is just personnal at the moment, with little real data to actually go on.

In terms of efficiency, I 'know' that investing in community turbines would bring more power per pound than micro-generation by a large margin no matter how you calculate it, but the psychological effect of power on the roof should not be underestimated.

I know of people who have halved their household's use of electricity (without nagging the rest of the family too much) since visiting (hugging) the electricity meter each day to see how much they were generating/saving. In my experience, a reduction in use is not as high when people simply switch to green electricity or invest in a scheme which they don't see on a daily basis.

There are also various dangers of 'overdimensioning' micro power. Vibration damage, annoying the neighbours, turbulence affecting generation etc. I would encourage starting out with a smaller device of only a few hundred watts peak power, and using some of the money then remaining to implement some of the energy-saving steps which then pop up psychologically 'out of nowhere'.