Modelling EROEI and net energy in the exploitation of non renewable resources

Recently, Bardi and Lavacchi (2009) showed that a simple system of coupled differential equations can be used for a quantitative description of the exploitation of non renewable resources in a free market economy. The present paper examines how the model describes the behavior of the system in terms of energy return for energy invested (EROEI) and net energy (energy returned minus energy expended). We show that the model generates a behavior of these factors comparable to the results obtained by other methods, for instance for the case of crude oil production in the US.

► The aim of this work is to examine how energy parameters such as EROEI (energy return for energy invested) and net energy (energy produced minus energy spent) are related to progressive exploitation of a non renewable resource such as crude oil.
► By using a simple dynamic model, we find that EROEI is proportional to the amount of remaining resource and that it may become smaller than one while production continues. We also find that the net energy of extraction has a maximum near the production peak of the resource.
► These results can be seen as a “mind sized” model that helps to understand the pattern of exploitation of non renewable, or slowly renewable, natural resources.