Maximum power and biology

Abstract

Neither the first nor the second laws of thermodynamics address the rate at which energy transformations or processes occur. But the rate of energy use is critically important, as is obvious in a foot race. In a competitive world, it is important to not only “out energy” one’s competition but to do it fairly rapidly, that is before the resource is captured by another individual or species. Power measures the rate at which energy is used. The concept of maximum power incorporates time into measures of energy transformations. It provides information about the rate at which one kind of energy is transformed into another as well as the efficiency of that transformation. As such it is critical to understanding the role of energy in evolution. For many years I struggled with, or ignored, the relation between EROI and maximum power, both large ideas about energy and biological or social evolution. They were both fascinating to me, just too different. Recently I think I have come up with a resolution: I now think of maximum power as a subset of EROI, it is a means of optimizing EROI by paying attention to time. Both maximum power and its relation to EROI will be developed more fully below.