In the present work we conceptualize energy as a productive input observing
its relationship with capital and labor. A translog cost function is used
to study the factor demand in the economies of Portugal and Spain, without
a priori fixing any given technological structure. We evaluate the underlyi
ng technology in each country. We relate the principal energy variables wit
h the technology, verifying econometrically the basic characteristics of th
e energy markets. The translog function is also tested for separability of
inputs. The results include consistent estimates for the Alien and price el
asticities by obtaining confidence intervals for elasticity estimators. We
find that there is a diversity of complement-substitute relationships betwe
en energy and the other factors. (C) 2000 Elsevier Science Ltd. All rights
reserved.