Industrial Metabolism: Theory and Policy

The word metabolism, as used in its original biological context, connotes the intemal processes of a living organism. The organism ingests energy-rich, lowentropy materials (food), to provide for its own maintenance and tunctions, as well as a surplus to permit growth or reproduction. The process also necessanly involves excretion or exhalation of waste outputs, consisting of degraded, highentropy materials. There is a compelling analogy between biological organisms and industrial activities-indeed, the whole economc system-not only because both are materials-processing systems driven by a flow of free energy (Georgescu-Roegen, 197 I), but because both are examples of self-organizing “dissipative systems” in a stable state, far from thermodynamic equilibriuni ( Ayres, 1988). At the most abstract level of description, then, the metabolism of industry is the whole integrated collection of physical processes that convert raw niatenals and energy, plus labor, into finished products and wastes in a (more or less) steadystate condition (Figure I ) . The production (supply) side, by itself, is not selfregulating. The stabilizing controls of the system are provided by its human component. This human role has two aspects: (1 ) direct, as labor input, and (2) indirect, as consumer of output (i.e., determinant of final demand). The Fystem I $ stabilized, at least in its decentralized competitive market form, by balancing sup-