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This morning's news that the Houses of Parliament is looking to install turbines next to its building and a recent blog post by Mel on the technology kicked me into writing a post which I've been putting off for a couple of week. This is also off the back of articles in Building Design and Building on two experiments to assess the performance of wind turbines, one in a city centre site and one in a more rural setting.
There certainly appears to be plenty of scrutiny attached to the potential of wind. More so than other renewable technologies, perhaps because the kit itself is that much more visible than other systems. The issue comes down, as ever, to practicalities. Do these things really work or not in enough different locations and in different sizes?
You certainly get some interesting feedback to these questions from the team behind the Hockerton Housing projects, who released figures on the performance of two systems it has on its site last week. Speaking to one of the members of the team there he seems to be of the firm opinion that roof-mounted turbines simply don't cut the mustard to present. "It's about wind speed and you just do not get that in urban developments," he said.
The Hockerton team are seeking improvements from the two manufacturers, Proven and Iskra, who have installed 6kW units on the site. They run through the practical problems of installation, from the obvious one of planning to the positioning - despite the systems being on open ground there has still been some affect from a belt of trees to the South West of the site. "It's affecting the wind speed," my man says. Yet that is not putting them off - the team is hoping to install a much bigger 225 kW unit, which will clearly offer a better payback. It's interesting despite this that the Hockerton team offer a useful ratio for those planning sustainable schemes - spend 90% of your effort on the building design and 10% on renewables.
Over in Southwark south London a team is aiming to prove the Hockerton opinion wrong, that urban wind can work. A team that includes Photon Energy and Brian Dunlop Associates has two systems, Proven again and Quiet Revolution, to see what results can come from 6kW units in tops of an 11-storey council block in Elephant & Castle. "We need to find out whether urban wind power is a worthwhile renewable energy source," says Photon director Michael Holmes in the BD piece. And the article ends by Holmes admitting that if the experiment fails to show the expected results we will collectively need to consider different renewable technologies.
It looks to me as though the case for small, sub-2kW roof-mounted turbines is now dead: every installation that has published results shows them to be useless.
The 6kW turbines are more promising but again the actual power output is frequently well below what the manufacturers suggest is possible. There is a 6kW Proven at the SmartLife Centre in Cambridge that has been in place for over a year (clearly visible from the A14 Northern By-Pass) and the output to date - which is displayed on an screen inside the building - has been bordering on the embarrassing.
Posted by: mark Brinkley | 13 November 2007 at 06:45 AM