Only a tiny fraction of the power goes into performing transactions; the total power consumed is independent from transaction rate. Bitcoin in 2009 used vastly less power than today yet had the same transaction capacity. The power consumption scales with the price of Bitcoin[1], which is determined by demand and most of the demand right now is driven by future price speculation.
Interestingly, the new cash-settled CME Bitcoin futures contracts, due to start trading in December, will allow speculation on the future price to take place without requiring possession of actual Bitcoin. These futures may both increase Bitcoin adoption and reduce the upward pressure of speculation on the price.
[1] More accurately, the value of power consumed for mining Bitcoin approaches the value of the block reward plus transaction fees.
You could say only a tiny amount of the power is used for transactions. But given that the transactions are the entire point of the network, all power used by the network ought to be counted towards the transactions, just like we’d count the power used by the lights in a bank towards their transactions even though the lights don’t directly do transactions.
The fact that the power used by Bitcoin is essentially independent of the number of transactions is interesting, but it’s not a plus for Bitcoin, since the network is at capacity already.
Interestingly, the new cash-settled CME Bitcoin futures contracts, due to start trading in December, will allow speculation on the future price to take place without requiring possession of actual Bitcoin. These futures may both increase Bitcoin adoption and reduce the upward pressure of speculation on the price.
[1] More accurately, the value of power consumed for mining Bitcoin approaches the value of the block reward plus transaction fees.