With only a very tenous grasp on the basics of fluid mechanics and thermodynamics, I'd suspect it is simply a lot more cost effective to drive a significantly l

With only a very tenous grasp on the basics of fluid mechanics and thermodynamics, I'd suspect it is simply a lot more cost effective to drive a significantly larger volume of water through a significantly shallower (hence, lower temperature - but cheaper to drill, maintain and force water through) well to reap the same amount of energy. Assuming reasonable heat exchange efficiencies, you'd do as well with 1000m^3/hour at a 20 degree differential as you would with 100m^3/hour at a 200 degree differential. Or am I missing something?