in progress… stay tuned…
EROI is Energy returned on Energy invested. In other words, EROI is the energy yield we get – our net return. Call it the ROI of energy. It is a distinct measure from energy efficiency as it does not measure the primary energy inputs to the system, only usable energy.
Here’s a simple hierarchy of EROI in our current infrastructure system. See any ‘issues’?
Figure:. “Pyramid of Energetic Needs” representing the minimum EROI required for conventional oil, at the well-head, to be able to perform various tasks required for civilization. The blue values are published values, the yellow values increasingly speculative. If the EROI of a fuel (say oil) is 1.1:1 then all you can do is pump it out of the ground and look at it. Each increment in EROI allows more and more work to be done. EROI chart from “EROI of Global Energy Resources Preliminary Status and Trends” Jessica Lambert, Charles Hall, Steve Balogh, Alex Poisson, and Ajay Gupta State University of New York, College of Environmental Science and Forestry ————————————————————————— EROI is one of the most important, unknown energy measurements.