Here is some information about optimal wind turbine power generation. Wind Turbines are limited by what is called the Betz law. Simply put, if you capture 100% of the energy available in the wind, you stop the wind. The Betz limit says that essentially, if you capture 59.6% of the energy in the wind, that is the best compromise between stopping the air and forcing it to go around your machine.
More windpower basics
Wind power figures from around the world and more about wind power
There is a $24 billion proposal to create a 10 Gigawatt on offshore wind farms and a large power grid for bringing the electricity in and to allow for extra grid capacity to allow for efficient sharing of electricity in Europe