Coal power plants have about 45% energy efficency. Liginte about 30-35%, Nuclear plants also about 30-35%. All the other energy ends up using water to cool it away.
So a 1 GW nuclear plant is putting about 2 GW of heat into the water. A lignite plant the same. A 1 GW coal power plant is only putting about 1.25 GW of heat into water.
But again the problem is the false comparison being made here. The alternative to nuclear isnt coal. the alternative is renewables in conjunction with storage technologies and smarter grid management with demand sheduling.
Edit: wow nuclear shills now downvoting basic physics.