WHEN it comes to wind turbines, every bit of extra power counts. Replacing the machines entirely can be a costly business, however.

So Siemens has unveiled three designs for enhancing the aerodynamics of turbine blades. The first, DinoTails, resembles the back plates of a stegosaur and increases the area of a blade, adding lift and so power. It also makes them quieter. When air flows from above and below the trailing edge of a turbine blade meet, they create turbulence, which can increase drag and make it noisy. The DinoTails’ serrated edge breaks up that flow, reducing the turbulence.

A snow-shovel-shaped device called DinoShells extends the blade shape down to where it joins the main shaft, making the turbine more efficient. The third attachment is called a vortex generator, featuring small fins that force the air to stay in contact with the top of the blade for longer, increasing lift. Siemens says combining the three could increase the energy output of an older turbine by up to 1.5 per cent. That may not sound like a lot, but the Altamont Pass Wind Farm in California – one of the world’s biggest – produces 125 megawatts on average. A 1.5 per cent increase there would meet the energy needs of an extra 2500 households.

The Altamont Pass Wind Farm could meet the energy needs of an extra 2500 households

Paul Veers, chief engineer at the US National Wind Technology Center says that such a small increase in power is often enough for energy firms. “If you can add one to two per cent to a big number, then it makes a difference,” he says. Siemens is installing the attachments to give a 3.15 megawatt boost to the Bison 2 and 3 Wind Energy Centers in North Dakota. Construction is due to be finished by the end of the year.