CASE STUDY 1: NET ENERGY FROM FOSSIL FUEL EXTRACTION IN THE UNITED STATES
One technique for evaluating the productivity of energy systems is net energy analysis, which compares the quantity of energy delivered to society by an energy system to the energy used directly and indirectly in the delivery process. EROI is the ratio of energy delivered to energy costs. There is a long debate about the relative strengths and weaknesses of net energy analysis. One restriction on net energy analysis’ ability to deliver the insights it promises is its treatment of energy quality. In most net energy
analyses, inputs and outputs of different types of energy are aggregated by their thermal equivalents. This case study illustrates how accounting for energy quality affected calculations for the EROI of the U. S. petroleum sector from 1954 to 1992.