Energy consumption per dollar of output in 2011 was 2% less than 2010 (7.47 thousands BTUs), and half of the energy required in 1979 (14.79 thousand BTUs).The graph is BTUs per real dollar of GDP.
Again, to repeat: The energy used in 2011 was half of the energy required in 1979 (14.79 thousand BTUs) per dollar GDP.
On top of this natural gas has never been cheaper (at least in my investing lifetime).
Most interesting aspect of the graph? Energy use vs productivity not even noticeable during the remarkable recessions. The graphic pretty much leveled off between 1985 and 1995, experiencing significantly declines prior to 1985 and after 1995. The largest drop was from 1975 to 1985.