Monday, July 25, 2005

A turn for the better

A turn for the better
Wind turbines are ugly and no one wants to live near one. Right? Wrong. Steve Rose on the new architects of spin

Steve Rose
Monday July 18, 2005


Think of wind power and the first image to spring to mind is most likely a giant, three-bladed propeller spinning atop a slim tower, probably in a rural area. Chances are that's actually the only image that springs to mind - and that's a problem. To renewable-energy supporters, the wind turbine symbolises the hope of a green, clean future, but to opponents, they might as well be Martian tripods from War of the Worlds, advancing inexorably across our precious countryside.
With Britain's plans for new wind farms proceeding apace in an effort to meet the target of 10% renewable-sourced energy by 2010, the debate has reached critical levels. Anti-wind farm groups have been springing up wherever wind farms are proposed; some opponents say they would rather have a nuclear power station in their backyard than see Britain's rural landscape covered in propellers on sticks. And as long as propellers on sticks are the only option, pro- and anti-wind farm camps are unlikely to ever agree.

The debate is clearly as much about the aesthetics of wind power as the politics and practicalities but, at present, wind turbines barely rank above electricity pylons in terms of aesthetic consideration. Members of the design community are beginning to rise to the challenge, however, either by finding better places to put wind turbines or by making them better looking.

One of the most striking new projects rethinks the idea of the turbine entirely. It is called an Aerogenerator and it looks nothing like a propeller on a stick; more like a cross between a glider and a giant harp, or perhaps a James Bond villain's mid-ocean hideout. Designed by Grimshaw Architects in association with Windpower Ltd, the Aerogenerator is arguably the first wind-turbine design to capture the spirit of pioneering optimism that these structures ought to express. It could also be a very practical option, especially since it would be situated offshore, far away from anyone's backyard.

While conventional turbines rotate on a horizontal axis, the V-shaped Aerogenerator, which would be as tall as the London Eye, spins on a vertical axis, like a record. At three revolutions per minute, one machine could generate up to nine megawatts of electricity, compared with an average of 2Mw from conventional turbines.

The Aerogenerator is descended from what's known as a Darrieus rotor, which resembles an egg whisk in shape, and works something like a sideways water wheel. It was invented by a Frenchman in the 1930s, and developed extensively in the US and Canada in the 1970s. Unlike horizontal-axis designs, vertical-axis turbines can harness wind energy from any direction, and because the moving parts and the generator are at ground level, they are easier to maintain. But building them on a giant scale presented major engineering difficulties, particularly in terms of stability. What the Aerogenerator does in effect is reproduce the effect of a Darrieus rotor, but with much greater stability. Which means that you can build a much bigger turbine without the danger of it tipping over.

"Our engineer thought about the problem and basically took it to pieces and put it back together," says Theo Bird, founder of Windpower Ltd, who is funding the project through a combination of a government grant and the money he was saving to buy a new house. "By being much larger, you can afford to build offshore, where there's more wind. Twelve wind farms of 100 units would meet the UK government's 10% target for renewable sources. And in the future, you could possibly double the power from each turbine by harnessing tidal power beneath the surface."

"Also, from an architectural point of view," adds Grimshaw's Eoin Billings, "we saw it as an iconic element that could go in the entrance of a harbour or an industrial area. It doesn't have to be invisible."

The Aerogenerator was originally included in Grimshaw's proposal for the redevelopment of Las Palmas in Tenerife, but the project now has a life of its own. A prototype is about to be tested, and if all goes well, the turbine should be relatively straightforward to produce, in three to five years' time. "We're trying to think bicycle technology," says Bird. "It's got to be something strong and simple to work at sea. The only thing that's new is the aerodynamic theory; everything else is proven."

Beyond making better-looking wind farms, there is also potential for integrating turbines directly into buildings. After all, if nobody wants wind turbines in the countryside, why not put them in the cities? Cities already have high-rise structures in which to incorporate turbines, and they would be far more in tune with a man-made environment than a natural one. Added to which there would be less need to transport the electricity large distances to its users.

A few buildings have attempted to incorporate wind turbines, but so far none have achieved it with any conviction. Richard Rogers proposed an integral turbine for his Tomigaya tower in Tokyo in 1993, but in more recent efforts, such as Terry Farrell's Green Building in Manchester, or Kohn Pedersen Fox's New York Sports and Convention Centre, wind turbines seem to function more as a conspicuous signifier of environmental credentials than a significant solution to energy requirements.

Other architects are striving to factor in wind-power generation from the start. Marks Barfield Architects, designers of the London Eye, put a spiral turbine in the core of their Skyhouse residential tower design that would generate enough electricity to light and power the building's common areas, regardless of wind direction. Their Liverpool Edge building also features spiral turbines on top of each lift shaft, which should supply 10% of the building's energy needs. Similarly, Make Architects' Spiracle Tower features a concealed vertical-axis wind generator at the top, and Bill Dunster's Zed designs have used wind power along with other sustainable methods.

Going the whole hog, though, a European Commission-sponsored organisation named Project Web (Wind Energy for the Built Environment) has investigated in detail a purpose-built wind-powered skyscraper. The aerodynamic form of the twin 50-storey towers funnels the wind into the three giant turbines, which would generate more power than stand-alone turbines. Under the right circumstances, the building could generate nearly all of its own energy needs, according to Sinisa Stankovic of BDSP Partnership, Project Web's environmental engineers.

"So far, none of the attempts to integrate wind turbines into buildings have been truly optimised," he says. "Wind energy is intrinsically a low-density source, so you cannot produce a huge output from a small machine. Overall, we think you have to aim for a significant contribution to the building's energy demand, otherwise it will be seen as a gimmick. To be serious you would need to go for 20% minimum."

Despite the proven efficacy of Project Web's designs (which also include a four-tower design that can harness wind from any direction), the realities of the construction industry have so far kept them on the drawing board. Stankovic believes it is only a matter of time, though, before the rise in oil prices makes wind-powered buildings commercially viable.

A little closer to becoming reality was the incarnation-before-last of the controversial Freedom Tower in New York, the replacement building for the World Trade Centre. At the top of this enormous tower, architects SOM intended to create a 150m-high open cage structure housing some 30 turbines. The skyscraper beneath it was shaped to channel the wind up into it, and it could have generated a quarter of the building's needs - a bona fide urban wind farm.

Perhaps predictably, other factors - not just commercial but also security-related - came to take precedence over environmental considerations. So instead of a powerful beacon advertising wind power's potential to the world, the Freedom Tower has become a bland, and slightly paranoid, office block. "It was probably the biggest disappointment of my life," says Guy Battle, of Battle McCarthy. Battle was consulting engineer for the project, and is something of a guru when it comes to environmental and sustainable architecture. Freedom Tower aside, he is convinced that the urban wind farm will soon be a reality.

"I know there's an economic case for it," he says. "The technology is well understood, it's robust and safe, and given the right location, wind energy has very good payback periods. If you go up in height, wind power output increases exponentially, so if you double the wind speed, you'll get eight times the power. There are massive gains to be had."

As energy from fossil fuels becomes more scarce and expensive, the energy performance of buildings can only increase in importance. Battle and others like him are thinking beyond mere environmental responsibility to an era where buildings, and ultimately cities themselves, are net energy producers. "Traditional buildings have been a drain on infrastructure - water, electricity, waste disposal, etc," says Battle. "Really we should be working towards something like an occupied infrastructure, just like windmills were once occupied. It's a paradigm shift in how we see buildings, and it means that architects are going to have to rethink their aesthetic. It's no longer about just responding to cultural and social urban factors. It's a whole different layer of architecture coming through that will begin to change the face of our cities."

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