EROI and the limits of conventional feasibility assessment—Part 1: The technical potential for renewables

A fundamental requirement that any energy supply system must satisfy for economic viability is a sufficiently high energy return on energy investment (EROI) for manufacturing, installing, operating and maintaining the system over its operating life. The question of what constitutes a sufficient return depends on the nature of the economy and society that the energy supply system is intended to support—while an EROI <1 implies a net energy sink, an EROI >1 does not automatically entail viability. Consider the limiting case in which net energy supply is zero, i.e. EROI =1. This would entail an economy consisting entirely of an energy supply sector that supported itself, but allowed for no economic activity beyond this. It’s certainly possible to imagine a functional economy along such lines, but it implies that every person living in such a society must dedicate their life to and focus all of their attention and effort on providing for the subsistence energy needs of their economic system. Such an economic system would serve no purpose beyond its own perpetuation; citizens of such a society might very well consider their lives to constitute a form of slavery to their economy. Continue reading

The economic view of systemic efficiency: rebound and backfire—Jevons’ legacy

As I stoke the boilers here at Beyond this Brief Anomaly after another (much) longer-than-anticipated intermission, it’s worth checking in on what this project has been all about to date. In a nutshell: I’ve attempted to make some modest in-roads into improving how we make sense of energy-related concepts, given the central role that I see for these in coordinating social action as we seek ways of living well together in the face of the increasingly urgent socio-ecological dilemmas confronting humanity. And in doing this, I’m drawing on principles from the field of inquiry known as systems thinking, or simply systems. If I were to try capturing what this means in essence, it would be along the lines of “considering the situations in which we’re interested as comprehensively as we’re able, by paying attention to their encompassing contexts.” The approach I’m taking extends this question of context to include considerations around cognition, language and meaning. Put simply, this implies treating the energy-related concepts that the inquiry deals with as sense-making “tools” and “artefacts” constructed by us. As such, they constitute important and influential parts of our shared culture. With them and through them, we bring our circumstances into being. What this implies is that the quality and coherence of our conceptual spaces “in here” affects the nature of our physical, social, economic, political etc. conditions “out there”. Attending to this “interior dimension” can have profound implications for the quality of the worlds that we bring about through the actions we engage in together. Continue reading

The economic view of systemic efficiency: energy return on energy investment

The last post looked at what I’ve called the engineering view of systemic efficiency, specifically the concept of available energy, or exergy. I refer to this as systemic because it considers energy conversion processes in relation to their specific operating contexts, in order to understand the useful work that a system can provide. While energy conversion processes serve an infinite array of human purposes, in the proximate or most immediate sense, we carry out energy conversions in order to do work—to effect transformations in our material worlds—and to provide heating (and while technically it’s not necessary to further differentiate it here, to provide illumination also). The systemic view provided by exergy analysis deals directly with the question of how much utility we can derive from an energy conversion process, and so it allows us to think about energy resources and infrastructure in a more concrete way than when we conduct analysis in terms of the nominal heating value of primary sources or fuels, in isolation from the particular situations in which they are used. Differences in energy use situations—different conversion technologies, implemented in different ways, operating in different physical environments—lead to differences in the utility that can be derived from an energy source. In establishing the efficiency of an energy conversion process—the useful energy output from the process divided by the nominal energy input—a focus on conversion systems and their parts (including the particular energy sources involved) only gets us so far. For a comprehensive view of efficiency we need to consider energy conversion processes in terms of all three levels of the basic systems hierarchy of system, sub-systems and supra-system. Exergy analysis provides the means for achieving this.

My reason for identifying this approach to thinking about efficiency as the engineering view relates in part to the scale at which exergy analysis’s systemic approach is most fruitfully applied—namely the plant or equipment scale. In other words, this is most immediately useful at the micro-economic or enterprise level, where we deal with technology components that make up economic units. In macro-economic terms, exergy analysis does have particular value for understanding performance of an economy’s energy sector, and also provides especially valuable insights in relation to transport and manufacturing activities.  Coming to terms, though, with industrial societies—or, as we’ll see, any forms of social organisation for that matter—in physical- or energy-economic terms requires that we look beyond the enterprise and even sectorial levels. That is, we need a basis for thinking holistically about societies and their economic forms that relates energy supply and use at the overall macro-scale. It’s for this purpose that the concept of energy return on investment (EROI) (or energy return on energy investment—EROEI), has started, only relatively recently, to be better appreciated as so important. EROI tells us about the energy available for economic activity other than the supply of energy itself, and it is in this sense that I referred to it in the introductory post on efficiency as, roughly speaking, the economic equivalent of thermodynamic availability. Continue reading

Post Carbon Institute’s ‘This is Our Energy Reality’: visualising this Brief Anomaly

I’m a little slow on the uptake with this one. The promotional slide show ‘This is Our Energy Reality’ was released on publication of the Post Carbon Institute’s book Energy: Overdevelopment and the Delusion of Endless Growth in October last year. I’d seen the book (and the accompanying Energy Reader), but only just discovered the slide show when I went hunting for a reference for the next post in the energy efficiency series, that will take a closer look at energy return on investment.

It’s a powerful addition to the occasional visualisation series that I started last year—and certainly no less relevant now than eight months back:

 

From the website accompanying the books, energy-reality.org:

Energy is at the heart of the human predicament in the twenty-first century, and we now face a transformational moment in our energy story. As we leave the age of seemingly cheap and plentiful fossil fuels and enter an era of extreme energy, the ever-rising financial, social, and environmental costs of fossil fuels can no longer be ignored.

How we embrace this moment may well dictate the very future of our species — and millions of others.  

Please join Post Carbon Institute in a national campaign to increase energy literacy, with the ultimate goal of remaking the energy economy as if nature, people, and the future mattered.

Fostering increased energy literacy lies at the heart of Beyond this Brief Anomaly, and the course ‘Energy for the Future’ from which it evolved. Seems like a very worthwhile connection to make here.

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

A comprehensive view of system performance

The perennial human interest in keeping a check on the costs of doing what we do is hardly surprising. In fact, the significance of this as an organising principle extends well beyond our own species: it plays an important role in the processes of biological evolution, where the viability of any organism depends on maintaining a sufficient degree of what we might call “energetic leeway” to weather the range of environmental variation encountered. In the human realm, it manifests in a perhaps more mundane way in the disinclination that people tend to have for working harder than necessary to do what they want to do—if there’s an easier way of satisfying our needs and desires, we tend on the whole to be good at finding it. Continue reading

Analytic perspectives on efficiency

In the last post I set out a rough framework for organising various aspects of energy efficiency that impact on the energy costs of the energy that we use. Accessing any energy source requires the use of energy; and only a portion of the overall energy that we use goes directly to the specific service that we desire, such as moving goods or people from one place to another. In some situations—for example, many heating applications—almost all of the supplied energy is converted to directly useful forms, but all energy conversions entail energy costs of some magnitude Continue reading