Posted by: aronchang | December 21, 2008

Energy Flows and Conversion Losses

At our November HCC meeting at which Tom Vautin and Nathan Gauthier spoke, we had a brief discussion about the flow of energy and how the production and use of electricity results in massive losses of energy as coal/natural gas/nuclear/renewables are converted into electricity in its usable form as that which we access through our plugs.  I wanted to make sure to follow up on that discussion.  The electricity we consume at the end of the line only accounts for about 1/3 of the total energy that existed at the beginning of the line.  These conversion losses are massive, and must be kept in mind when people ask whether or not it really matters for someone to switch off a light bulb or to take other measures to save energy; the true amount of energy saved (and thus resources conserved and pollution avoided) is far greater than the electricity that would have been used had that light switched not been turned off.   And this is why cutting energy demand and use is, by far, one of the most important means for achieving dramatic improvements in the reduction of greenhouse gas production and other indicators of environmental health.  Please visit the Dept. of Energy website to see an energy flow diagram for the United States.

Or check out this Sankey diagram: 

US Energy Flow, Sankey Diagram

US Energy Flow, Sankey Diagram

The same website where I got this diagram has other versions, some for different countries, some of which are beautiful, and all of which illustrate this essential point:


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