High-level energy

An international engineering team is building a prototype airborne wind turbine that could be moored at high altitude.

An international engineering team is building a prototype airborne wind turbine that could be moored at high altitude to provide a constant source of renewable energy without impacting on local landscapes.

Australian Bryan Roberts, a professor of engineering at the University of Technology in Sydney, said clusters of flying electricity generators (FEGs) could stay aloft for months powered by their own electricity while feeding power to the ground through a cable.

Researchers are increasingly interested in devices to generate energy at high altitudes, where winds are persistent and strong. A Dutch team at Delft Technical University recently unveiled a concept to generate electricity using a chain of controllable kites, with each ‘Laddermill’ capable of generating 100MW. But the researchers are four years away from building a working model.

Roberts has teamed up with San Diego company Sky WindPower to build a 200kW demonstrator craft with four rotors arranged in a square at altitude.

The helicopter-like system would hoist the turbine into the troposphere to an altitude of around 15,000ft. Recent advances in lightweight tether technology mean that very little electricity would be lost as it was fed back to the ground and into the national grid.

According to the researchers’ statistics, FEG power generation could be used at locations all over the world. Such a system would work particularly well in the UK as it would be able to harness Gulf Stream winds.

The group estimates an area of restricted airspace of around 15–30km would be required to accommodate approximately 500 FEGs, each producing 20MW or more. The installation could have a total output of 10,000MW, equivalent to that of a very large power station.

Roberts claims the company can produce electricity for just over 1p per kW/h. ‘Importantly there is no visual pollution similar to that attached to ground-based or offshore wind turbines. Also there is no noise from the units parked at altitude,’ said Roberts.

At certain locations the generators would have an efficiency of 90 per cent, three times higher than turbines at ground level.