renewable idea

i don't claim to be clever, but i have had an idea, and i want to see what you guys have to say.

here goes.... i have noticed that power stations are not very efficent ie. there is a lot of heat wasted when boiling the water turn turn the turbine. so, why not inslulate the fire with wood, from a renewable source, a forest that is grown specalliy for the purpose. the wood would turn into charchol, which would then be used to be burnt, and more wood would be placed into the insulating place on the outside of the fire (i dunno how to insert pics, but if someone would tell me, then i could insert a diagram) the forest growning nearby would take out the carbon emmisions and make the station not contruibute to global warming.