China taps high-altitude winds for power generation by flying craft to 4,000m

China has successfully flown an airborne wind energy system to a record height of 4,000 meters, generating electricity from the sky in what state broadcaster CCTV called a world-first achievement. The prototype S4000 craft, roughly the length of a Boeing 747 and resembling an airship, completed a full work cycle at a test site in northwestern China, including ascent, station-keeping, power generation, and recovery.

Filled with helium, the craft carries lightweight turbines and harnesses stronger, steadier winds at high altitudes to produce electricity. It can also be quickly moved between sites, making it ideal for providing power in remote locations like deserts, highlands, islands, and disaster zones. Developed by Beijing start-up Sawes Energy Technology in collaboration with Tsinghua University and the Chinese Academy of Sciences, the S4000 is part of a series of models with increasing altitudes, starting from the S1500 at 1,500 meters.

The developers estimate that electricity generated at 3,000 meters could cost nearly as much as conventional ground-based wind power, while at 9,000 meters, the systems could operate for over 8,000 hours a year at a cost of less than half a US cent per kilowatt-hour. China's 15th five-year plan for renewable energy calls for exploration and research into high-altitude wind power and other new forms of wind-generated electricity.