Tuesday, December 20, 2011
Lawrence Livermore National Lab released the 2010 version of the US energy use flow chart recently. I find it useful for introducing students to the big picture of our energy use.
It shows that nine major types of energy sources (petroleum, natural gas, coal, nuclear, etc.) with a total energy content of 98.0 quadrillion BTUs (quads) supplied US energy demand in 2010. Of the 98 quads, 41.88 were ultimately consumed as energy services in the residential, commercial, industrial and transportation sectors, while 56.13 were lost (“rejected,” or wasted energy), generally in the form of waste heat and transmission line losses. In other words, our energy system has an overall efficiency of 42.8% (41.88/98.0).
Comparing with previous years (2008, 2009 and 2010 available here), we can observe that we used 3.4 more quads (almost 4%) than in 2009, but 1.2 fewer quads than in 2008. How are renewables faring? Wind energy has almost doubled from .5 quads in 2008 to .92 in 2010. Solar has grown less substantially over the same time period, from .08 to .11 quads.
- Lesley McAllister