ABSTRACT
The energy cost of a product is a deceptively simple concept: it can vary widely according to how it is calculated. This chapter explains the origin of the variations in results obtained by different workers and examines the aims of various investigations. There is no ‘correct’ way of apportioning energy costs or of choosing the boundary that defines the subsystem being studied, but the methods adopted must be consistent with the overall aims of the analysis. Three types of method currently in use are reviewed by the author: statistical analysis, input-output table analysis, and process analysis. Examples are given of their application to copper smelting, electricity supply, oil refining and aluminium production. A bibliography of some of the important literature is given.
