The innovators: US scientists harness the power of evaporating water

A team at Columbia University hope to use the energy produced by bacteria when they expand and contract

A small Lego device on the shelf of professor Ozgur Sahin's office at Columbia University could open up the possibility of another form of renewable energy, and one that is much cheaper than solar and wind.

Sahin has used the simple gadget to prove that evaporating water can be used to generate power, which could eventually lead to energy being generated from still reservoirs. At the centre of the research by Sahin and his team in New York are spores of common soil bacteria that expand, much like a muscle, when there is moisture in the atmosphere, and contract in drier conditions.