Most commercial turbines being assembled onshore in Sweden today (2012) have blades that are about 50 meters long. Offshore turbines have blades up to 70 meters. An 83 meter blade was sent to a testing facility in October of 2012.
Yes The Steam Engine/Tractor is still being use to this day.
Where it will have the most wind hit it obviously...usually where flat ground is apparent.
To help reduce their visual impact as much as possible. The skies across North America and Europe are most often grey or off-white, so the turbines are painted the same colour. Painting them green or blue would actually make them stand out a lot more!
An odd number is always preferred. This decreases off axis torque on the shaft as the lower most blade aligns with the tower. Three is typical for industrial turbines, I believe it's a weight / combined blade length ratio. Smaller home turbines may have many blades and an annulus (to limit tip losses) for higher power densities.
Denmark
No, Denmark is not an island, but it is a European country.
denmark
Denmark
Denmark, or most likely it's Denmark
Most regions. Concentrations are in Northern Europe (Denmark gets 40% of their electricity from wind turbines).
In 2006, 2007 and 2009 the most advanced country was Denmark.
Denmark
Denmark
Denmark
Denmark
Denmark