Google buys high-flying Makani

US high-altitude wind-energy developer Makani Power has been bought by Google, cementing earlier investments in the start-up by the internet giant.

Makani is fine-turning a 600kW turbine-outfitted "tethered wing" concept that generates power while flying between 250 and 600 metres above the ground.

The developer says the Google acquisition "formalises a long and productive relationship between our two companies,and will provide Makani with the resources to accelerate our work to make wind energy cost-competitive with fossil fuels".

The California company says the "timing couldn’t be better", given the recent completion of maiden autonomous all-modes flight with its Wing 7 prototype.

"We look forward to working with our new colleagues at Google[x] to make airborne wind a cost-effective reality."

A report last year by consultancy GL Garrad Hassan identified 22 companies that are developing high-altitude wind turbine prototypes, including kites, kytoons (a kite-balloon hybrid), aerostats, and gliders or sailplanes with turbines or airfoils attached.

These turbines are based around a flying tethered object that uses a mechanical system to harness kinetic energy from the wind anywhere from 200 metres to 20km above the Earth.