Not really. Since bitcoins specifically ties mining activity to confirming transactions it's fair to link them. Now could it cost a lot less energy to confirm a transaction? Easily, but the design of bitcoin ensures that people will 'waste' as much energy as economically feasible to mine them and thus ensures the energy cost will remain high.
This is epically true since bitcoins whole purpose is to conduct transactions so it would be fair to consider all the computers, network equipment, man hours, etc in the entire system as a direct cost of conducting those transactions.
This wouldn't be any different then looking at all of Visas equipment and energy costs and dividing by the number of transactions it conducts per day to arrive at a 'cost' of swiping your credit card.