Ah, I see what you mean. Relating 'energy' to fees. Though to me it seems almost negligible to the moderate user. I have sent several transactions with IOTA and it only takes but a minute to POW on my laptop in the background. I hardly notice it going on. Sure my CPU kicks up a bit, but that's about it. I see what you mean though, for someone making large amounts of transactions it would take a bit more computing power (i.e. electricity and fees) to conduct them.