You mean that when I send .1 BTC from one wallet to another that costs $5 of electricity?
The electricity consumption of the Bitcoin network is much the same whether or not you send your .1 BTC payment, so there's no incremental cost. But if you divide the total electricity consumption by the current level of transactions, it comes out around $5 of electricity per transaction.
Therefore, if you had ten times as many transactions, each one would only be associated with approximately $0.50 worth of electricity.
In the longer term, the electricity consumption will vary according to the hashing power of the network, which will be driven by the exchange rate and also by mining fees. But in the short term, more transactions equals less electricity per transaction.
To see this, consider that the block reward of 50 BTC is worth over $200. So miners would be happy to spend up to $200 of electricity to mine a block. If the block contains 40 transactions, that comes out to $5 per transaction. Sure it's not quite that simple, for example because people pay different amounts for electricity, but that's the rough idea.