A New Approach to Calculating the "Corporate" EROI

The EROI is one of the most important indices to evaluate the net energy output of a source of primary energy (there is a lively debate on the usability of this kind of parameter, but here we will use it under the hypothesis that it is a good way to establish if an oil company has a level of efficiency close to other energetic sources). It is generally defined as the ratio between the energy extracted by a given resource and the energy costs sustained to extract that energy. We tried to set up an alternative method for the calculation of the EROI, taking (1) as a proxy of the energy costs the available data about the CO2 emissions of the oil companies, as reported in the sustainability reports (SRs), recommended by the international organisms such as IPCC and WBCSD, although not mandatory, and (2) as a proxy of the energy extracted the CO2 emissions estimate obtained by a stoichiometric conversion of the oil/gas production declared by the oil companies. Both proxies have been also corrected to take into account the different CO2 emission rate per unit energy of oil and gas. The resulting estimates of EROI are rather homogeneous and not too different from the values reported in the literature. The method could be suitable for year-by-year comparison of the time evolution of this important energy quality parameter for the individual energy producing and energy-delivering companies.