Jouni Valkonen <jounivalko...@gmail.com> wrote:
> Second argument is that with advanced blades materials, such as carbon > fibers and futuristic graphene, it is possible to make rotors up to 250 > meters in diameter. This can boost individual wind turbine output up to 20 > MW. > When the maximum length of the blade increases, estimates of total potential wind energy increase as well. These estimates are based on studies of wind, but they are predicated on the maximum size of a wind turbine at the time of the study. That is conservative, and reasonable. To put it another way, the studies assume the blades will sweep a certain cross-section of the sky. When the blades reach much higher, that increases the total wind they intercept. As people have pointed out here before, if you could loft the turbines into the jet stream with gigantic kites, that would change the equations completely. That would unlock unthinkable amounts of energy. That is assuming Keith's "wind shadow" hypothesis is not a major problem. Wind shadows are a problem of course. Turbines have to be sited carefully to avoid them. Wind shadows have been a problem for 4,000 years, since people began using sails. Captains sailing ships in battles, fishing fleets and modern regattas have made use of wind shadows for thousands of years. This is called "stealing the wind." - Jed
