Back to nature: hydropower goes helicoid

Engineers have long known that some of the best designs are to be found in nature, although they may not always be obvious. It took a chance meeting between a hydropower engineer and a medical scientist five years ago to discover that the energy output of hydroelectric stations could be boosted by up to 10% by adopting the spiral-shaped plumbing of blood vessels. The swirling effect created by helicoid penstocks and draft tubes appears to reduce head losses significantly and also prevent siltation and allow more compact plants. As this paper points out, the breakthrough certainly strengthens the case for future hydropower schemes. But it also serves as a reminder of the potentially great advances that can be made from a closer study of natural forms and systems.