It is definitely possible depending on the size of a farm and what water requirement is required for type of crop you are farming. He should have stated volume of water required instead he is allowing each individual decide how much water that is required. I think, you are going to get a vast difference If you were to ask average American how much water is required for a farm. I think, it's a innovative idea and it can be very successful in generating a clean energy but to generate vast amount of any energy you need vast amount of resources. This is just a simple fact that there is no free lunch!