1. The efficiency of any thermal source is low, because we have a lot of wasted power by heat. If you are talking about output power parameter should not be any difference. I think you should be more specific. for example ¿is 96MW the nominal power of the turbines?
its basic differance in the the hydro power plant is that it is having low sppeed reaction type blade turbine & in thermal plant it have a high speed impulse/reaction type blade turbine that is the measure differanc. Also as per size hydro turbine is 10 times approximately big as compare to thermal turbine at the same size