A History of Energy Forecasting in Economics and Some Reflections on Structural Change[Une histoire de la prospective énergie-économie face au défi du changement structurel]

The origins of energy forecasting in economics are usually traced back to the 1970s. This article focuses on earlier periods, analysing how some economists have examined the future of energy supply and demand since the 19th century. We show that most of the extrapolative and quantitative techniques used from the mid-19th century to the 1970s led to persistent difficulties in addressing structural change (technical progress, changes in energy sources, in consumption behaviours, etc.) and therefore in envisioning relevant energy futures. On the basis of Nicholas Georgescu-Roegen's 1970s proposals to improve forecasting exercises, we set out two principles for dealing with structural change in the design of energy futures: (i) to pay attention to the emergence of "novelty by combination" in the economy, and (ii) to condition the scenarios to the directions suggested by the principles of thermodynamics, in particular with regard to energy degradation (especially of fossil fuels).