The prospect of covering Buttermere or Loch Lomond with giant “evaporation engines” made out of artificial muscles might be enough to rouse William Blake from his grave. Yet these dark satanic water-mills could harvest renewable energy more efficiently than wind turbines or solar panels while also conserving lakes and reservoirs, scientists say. Two years ago Ozgur Sahin and his colleagues at Columbia University in New York built a machine powered by an elastic band that could drive a tiny car by soaking up the water evaporating off a small puddle at room temperature. The researchers have now calculated that their technology could provide up to three times as much power as a wind farm with the same area. They estimate that natural evaporation can yield between 2W and 10W per square metre. If they are right, cladding Lake Windermere in the machines would produce at least 29.5MW, enough to meet the electricity demands of 65,000 households. The miniature prototypes, which cost £3 each to build, rely on stretchy plastic strips that can be grown in a vat of bacteria. These expand to as much as four times their original length as they absorb water from the humid air just above the surface. When the material is full, shutters open overhead so that it dries up and shrinks.
Times 27th Sept 2017 read more »
Independent 26th Sept 2017 read more »