Germany's population is a quarter that of the US, and less than 4% the size of the US. Completely incomparable.
Secondly, there is not a single wind farm anywhere in the world that will pay itself off, economically or ecologically.
Furthermore, there is not enough ample wind resources in America to provide the general population, especially in urban environments, with adequate energy. Where it does occur tends to be large open, unpopulated expanses; technology to store and transfer energy from there, to where it could be used is extremely poor.
Alternative energy is only suitable when decentralized and used in highly localized (even micro) environments.