Forcing a dynamic model for oil production and EROI evolution: The Oil Game
Résumé
Since 1940, many attempts to model world oil production have been proposed. These approaches, using increasing complexity, consider the growing and decay of production independently of external, time-varying, causes. It is here proposed to extend the production equation by modelling a dynamic dependency between oil production and its Energy Return on Energy Invested (ERoEI), based on mass and energy conservation. The ERoEI equation is derived according to the second principle. It leads to a Lotka-Volterra set of equations, which can be applied to all liquid fossil fuels. The model obtained, after comparison with oil extraction and ERoEI evolution on the period 1960-2010, illustrates the production dynamic and the existence of an external, controlling parameter: the investment rate, which account for the re-investment in newly operating liquid fuel sources. The evolution of this parameter provides some possible explanations about the progress of the oil shocks and also some possible explanations about the peak prediction issues of the classical Hubbert model. Studying this evolution also suggests an attempt to control the liquid fuel production in order to obtain a linear time evolution on the period 1960-2010 through an apparently linearly growing investment rate: the oil game. Unfortunately, in order to keep a linearly growing production at long time scale, the investment rate has actually to evolve exponentially: the linear growth is in fact a short time scale approximation of the control required to play the oil game. The model also allows to highlight a major issue in liquid fuel production: even if the gross product can be controlled and keeps growing linearly, the net product, which account for the energy delivered by the oil industry to the world, is falling down faster and faster, due to the decrease of ERoEI. At some point, the net energy benefit will be equal to zero and liquid fuel production will stop, except if energy is given to the oil industry to keep extracting oil. In anyway, liquid fuels would become an energy sink instead of an energy source. Based on the model presented in this study, this will happen between 2027 an 2033. Production of liquid fuels could therefore keep growing linearly until this point, where a quick collapse is expected. Hence production will be strongly asymmetric regarding the peak, contrary to the prediction suggested by Hubbert’s model.
Origine | Fichiers produits par l'(les) auteur(s) |
---|
Loading...