The engineering view of systemic efficiency: available energy

So far in looking at the broad topic of efficiency, we’ve focused on what I described in the introductory post as the analytic perspective. In this post I’ll start to consider the systemic view of efficiency in more detail, by taking a closer look at the concept of available energy: the maximum work output achievable when a system is brought into equilibrium with its environment (or, as the corollary of this, the minimum work input required to bring about a given change in a system’s state). Continue reading

Introducing efficiency: the energy costs of energy supply and use

In an earlier series of posts (Fueling an industrial world and Energy and the biophysical view of economic activity: from joules to fuels) I pointed out how aggregating energy sources on the basis of their nominal heating values—as is common practice for our most prominent and influential energy information agencies at national and international scale—tends to obscure the dependencies between concrete economic infrastructure and the specific forms that energy sources take in practice. The aggregation process involves taking a highly abstract view of energy sources—a view that highlights only one narrow parameter, at the expense of most of what is important for appreciating how our physical economy functions. One of the most critical areas of omission relates to the energy costs of energy supply and use. Continue reading