Wind can be an unpredictable and unstable source of power, and high in the sky where it is more stable, it's difficult to exploit. Airborne wind turbines could provide a solution to this problem, but although the idea has been around since the 19th century, it's never been exploited on a larger scale. California's Makani Power aims to change that with its innovative flying wing turbine design. Wing 7 is essentially a cross between a UAV and a wind turbine that's tethered to a ground station from which it ascends to a height of around 1,300 feet (400m) and flies autonomously, generating up to 20-kilowatt of power in a 20mph (35km/h) wind.
Read the full article: Flying wing prototype takes wind-power to new heights