Cost of energy

30 May 2007

Which kills more birds - a wind turbine or a tall building? And why does it matter so much to clean technologists?

That's a question that came up at last week's Cleantech 2007 conference in Silicon Valley during a presentation from Sandia National Labs, the US government-owned operation charged with developing technologies for national security. While much of Sandia's work is in the field of nuclear weapons, non-proliferation and homeland security, one of its five areas of focus is energy and infrastructure assurance - reflecting the close link between global energy and global conflict.

The US Department of Energy got particularly interested in wind energy during the 1970s energy crisis, and during the 1980s California led the field before ceding ground to Europe. Today, according to Sandia's Dan Laird, four companies are responsible for 75 per cent of wind turbine supply, led by Vestas of Denmark and with one representative each from the US, Germany and Spain.

Like many alternative energies, wind power has its critics, not least because of the high number of birds killed by the turbines' giant blades. Altamont Pass in California, which houses one of the oldest wind farms in the US, has a particularly controversial record - sited on a migratory route, there have been numerous studies into the high number of raptors that are killed there each year.

So how bad is the problem? Research findings vary, but Laird argued that for every 10,000 birds killed by human activity, less than one death is from a wind turbine. By contrast, 5500 are from buildings and windows, 1000 from cats and 700 from vehicles.

Statistics, of course, mean different things to different people, and not everyone takes comfort from absolute numbers. For one thing, most people would see a difference between a sparrow hitting a window and a protected species like a golden eagle being taken out by a turbine blade. For another, there are a lot more buildings than wind turbines. And for a third, even with far better understanding across the industry of ways of mitigating the avian issue, as the number of turbines grows, so will the problem.

The flipside, as Laird points out, is that wind energy offers cost stability from an inexhaustible supply, and reduces energy risk - all of which is important to Sandia's mission. And unlike other forms of energy, it generates no waste and doesn't use up valuable water resources. So it's got a lot going for it compared to traditional dirty fuels.

The bottom line, of course, is that nothing comes for free, and every form of alternative energy brings some kind of compromise. Just ask the guys promoting nuclear power as a cleaner alternative to oil and coal...

By Keith Rodgers