Fuel conserving (and using) production functions

This article compares eight production/cost functions used or potentially useful for exploring how energy efficiency gains affect energy consumption. We show the practitioner's choice of function can inadvertently pre-determine results, and make recommendations as to which functions are flexible enough to prevent this. We also show pre-selected factor substitution elasticities can similarly pre-determine results. To aid the comparison we decompose the energy consumption “rebound” effect into intensity and output/income effects, which also delivers insight into the mechanisms of rebound. We conclude by recommending practitioners restrict themselves to either the Gallant (Fourier) or the Generalized Leontief/Symmetric Generalized Barnett cost functions as being sufficiently “rebound flexible.” The Translog cost function may be suitable given certain conditions and a particular form of the CES (Solow) function is a possible, but problematic, candidate. Along the way, the article provides a general methodology for similarly examining any arbitrarily-defined constant returns to scale production or cost function.