Agreed. Indeed, if you follow the concept of Matrioshka shells or brains (http://en.wikipedia.org/wiki/Matrioshka_brain http://en.wikipedia.org/wiki/Matrioshka_

Agreed. Indeed, if you follow the concept of Matrioshka shells or brains (http://en.wikipedia.org/wiki/Matrioshka_brain http://en.wikipedia.org/wiki/Matrioshka_brain), when energy is released as heat after computation another layer sitting outside the previous one takes advantage of the heat to power further computation. By placing enough shells going outward, you effectively release very little energy. Possibly less than or equal to the CMB.