If your only problem with a quantum computer is the energy required to run it, then you have a very good problem. edit: it might make sense to be worried about

If your only problem with a quantum computer is the energy required to run it, then you have a very good problem. edit: it might make sense to be worried about the feasibility of cooling it, since I think the infrastructure required for keeping the quantum-y parts of the computer cold is extensive, but the actual energy itself is probably irrelevant.