Google has acquired a US start-up that generates power using turbines flying on robotic tethered kites.
Makani Power will become part of Google X - the secretive research and development arm of the search giant.
The deal comes as Makani carries out the first fully autonomous flights of robot kites bearing its power-generating propellers.
"Success is not measured by what you accomplish but by the opposition you have encountered, and the courage with which you have maintained the struggle against overwhelming odds." -- Orison Swett Marden