Researchers in Italy have developed a new a form of wind turbine called KiteGen. The vertical axis turbine uses power kites. The kites are computer controlled by winches that are able to adjust the altitude (up to 2000m) and orientation continually to give optimum performance. Also with the assistance of radar the kites can avoid aircraft and even birds. The researchers believe a 100 metre diameter KiteGencould provide up to 500 MW at about £1 per GWh, the current average cost for electricity generation in Europe is about £30 per GWh. They also envision a KiteGen 2000 metres in diameter that could generate 5GW.
Here is an artist's impression: -
The official site (mostly in italian) is here, an interview with the disigner is here and an article about it on Wired News is here.