By addressubg the interface between the general economy and the energy activities that form a specific own right, Professor Maillet’s paper touches a crucial issue that is relevant throughout this conference, and, in fact, far beyond. And comparison of alternative energy forms or comparison, whether costs, availability, pollution potential, etc. A particular choise reflects a particilar viewpoint within the general economy. In most cases thes viewpoints are implicit, unreflected and introduced via ad hoc preferences for certain criteria.