This week’s edition of Scientific American has a couple of great infographics put together by Mason Inman on Energy Return on Investment (EROI). Strangely, these graphics are behind a paywall on Scientific American’s web site but are available open access on the site of Nature, the sister publication, here (click for larger image).
The infographics show that we are needing to use an ever-larger amount of energy in order to harvest energy from liquid fossil fuels. From a world in which we used to invest one unit of energy in conventional land-based oil production and get perhaps 50 units out, we are moving to a world where we now invest one unit of energy in unconventional fossil fuels but only get five or six units out.
For those interested in the source of the numbers that sit behind this graphic, then Inman has done us a service by listing them all here. As would be expected in any piece on energy extraction efficiency, he also references Professor Charles Hall, the father of EROI and, indeed, conducts a Q&A with Hall here. If you want to understand the implications of a low EROI, Hall explains it this way: Continue reading