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On EROEI

Energy Return On Energy Invested and its variations is a metric frequently used to look at our efficiency in harvesting energy with respect to the energy input. As an aside, regarding fossil fuels in day to day use we talk about energy production when strictly speaking we don’t produce coal/oil/gas but extract it and sometimes convert it.   Strictly technically speaking fossil fuels as well as renewables are solar energy; one is previously accumulated stock and the other is flow. Think balance sheet versus income statement. EROEI is an attractive concept but has a number of issues which can reduce its utility significantly.   The main issue with EROEI is that it suffers from boundary issues along a number of vectors. 1.        The first boundary issue is that although it is relatively easy to measure the energy produced it is significantly more difficult to determine the energy consumed in producing the energy. Should only direct energy inputs be counted (for example the ene