Saturday, August 12, 2006

Building-integrated wind power?

Wind Turbines on the Edge: Small Wind Power Could be Moving in Next Door: Covers a new wind turbine designed by Aerovironment. The turbine is small enough to be mounted on buildings, along the top edge of the wall (the parapet) where the wind is strongest. The turbine is designed to spin slowly, which will help it be safe for wildlife, as well as the screen in front of the turbine.

The AVX400 is the name of the product. Aerovironments is said to have spent a fair bit of time studying how to make the turbine look nice, so that people are more accepting. Obviously if people are saying wind turbines are eyesores, they'll be resisting having them on buildings. But if they look like sculptures would they be more accepting? Clearly there is a lot of wind happening everywhere, wind that can be captured to satisfy power requirements in office buildings or factories.

One common criticism of wind turbines is they tend to kill birds. However that idea comes from the wind turbines installed in California, especially in the Altamont Pass. Those turbines have been studied heavily to learn lessons about the bird death issue. What was learned is the placement and design of the turbines contribute the most to bird death. For example if the turbine itself has ledges on it, the birds will tend to perch on the turbine, and then be hit more frequently by the blades. But if the turbine is designed to not have ledges, the birds don't have a place to perch, and don't spend time near the blades.

What's more important for the AVX400 is, if the turbine is placed in places birds fly then the birds spend time near the turbines and have a greater risk of being caught in the blades. Where birds tend to fly seem to be near cliffs and hilltops, because of the winds. In the Altamont Pass, the turbines are placed along the ridgelines and hence are right where the birds are flying. But this is similar to the parapet of a building so would birds tend to fly near building parapets? I don't know, but that is exactly where Aerovironment suggests installing the AVX400.

However they have done two things that are known to reduce the danger to birds. First the blades are said to spin slowly, giving the birds less danger and greater ease with avoiding the blades. Second they put a screen in front of the blades.

This isn't the first wind turbine that's designed for beauty. An interesting twist on wind energy is also designed as sculpture, and is designed to be integrated with buildings.

The home page on this product is: Energy Technology Center: Projects Architectural Wind

Another article is: Wind Turbines on the Parapet

This has me wondering about the general state of integrating wind turbines with buildings. You don't see this very often, so why is that?

A couple obvious issues are the bird kill situation discussed above. Note that birds die when they fly into buildings, which happens all the time anyway. Another obvious issue is noise, as wind turbines are known to make some noise. Though urban areas are hardly quiet so I doubt noise is a proper issue for an urban area.

Ecofys BV appears to be a Netherlands company specializing in wind turbines for urban areas. However the web site is "under construction" and has little information.

Rooftop Turbines: Rooftop Mounting and Building Integration of Wind Turbines is an article giving a very clear diatribe against integrating wind turbines with buildings. This has apparently been tried several times, with bad results. For example the vibration from the turbine damaging the building, destroying the turbine, and the turbine then fell through the roof of the building. Another issue is that any noise the turbine makes will transmit directly to the frame of the building.

It's clear the turbines discussed in that article are designs that don't specifically decrease vibrations and noise. It's unknown whether Aerovironment has done a good job addressing those issues.

Launch of rooftop wind turbine pilot is a project in Scotland from 2004 to build a wind turbine onto a school in Fife. The article discusses the Energy Savings Trust and says some nice things about Scottish ingenuity. However the project is not mentioned anywhere else which can be found so it isn't clear whether there was any results or whether they abandoned the project. Swift route to green energy at home also covers the project.

UK's 'first' building-integrated wind turbine and PV system to go up discusses a building in London that combines solar panels and wind turbines.

Mini-turbines spell hope for building-integrated wind power discusses several wind projects integrated with buildings. Especially mentioned is the Aerotecture turbine discussed above.

Micro-Wind for the Home looks at several building-integrated renewable energy alternatives including wind turbines.

Renewable Devices offers the Swift turbine, which was involved in the school project in Fife mentioned above. While their site doesn't describe results from that project, it does show pictures of their turbine installed on buildings, including a supermarket. (Tesco is a popular supermarket chain in Scotland)

United Kingdom: Go with the wind covers wind turbines for buildings, especially focusing on the Swift turbine. It includes quotes from users of the Swift turbine.

Small scale wind discusses how wind power can be used on small scales. But it doesn't discuss urban use.

Small Wind Technologies: Building-integrated and stand-alone systems is coverage by the British Wind Energy Association.