What do you think is the best alternative energy source and why?

This last few days I been learning a lot about other types of energy and the contributions and problems that could cause to the environment. One of the energy sources that I think is the best and can substitute fossil fuels is wind power. This type of energy is renewable, does not contaminate the environment, and it is not as expensive as other types of energy. The United States gets 4.1 percent of its electricity from wind power. Iowa and South Dakota get more than 25 percent of their electricity from wind. Some of the side effects from wind power could be loss in birds and batts, but it can be prevented by analysing the place where the wind plant is gonna be built so is not near places where different types of birds could be affected. Wind energy helps avoid a variety of environmental impacts since is clean energy.  :)