I was preparing to completely disagree with you, but then looked at the data[1] and it seems the energy consumption per capita in the US and the UK is sort of stable over the last 20 years. That said, world average is about a quarter what it is in the US, so it may be growing for a long time to come.
[1]: http://data.worldbank.org/indicator/EG.USE.ELEC.KH.PC