This depends on whether you mean most energy out of all countries, or most energy per person in that country. The highest energy use per capita (per person) is definately the United States. If everyone used the same amount of resources as the average North American we would need 5 planets 🙁
It’s interesting that we can try and measure ‘quality of life’ and look at how that is related to the energy we consume. The calculations show that you don’t need a huge amount of energy to have a decent quality of life. America uses more than it really needs, but the ‘quality of life’ is no better than it is in Europe. One reason for this is that America is a big place so they have to travel longer distances than we do … but they could definitely do more to cut down 🙂
I’ve cheated here and gone to Wikipedia (so it must be true…….) Surprisingly the countries that use the most energy per person are several of the Arab states (because they burn lots of oil to work their air conditioning) and Iceland (because they use lots of free geothermal energy. The highest consumption per person is Qatar and the lowest is Bangladesh. Somebody in Qatar uses about 150 times more energy in a year than somebody in Bangladesh. The United States uses about half as much per person as Qatar but there are a lot more Americans than people in Qatar so the United States is the biggest consumer by far. I’ve just come back from Florida so I can say that is true.