I’ve been asked a few times now to provide an account of the energy transition modelling featured on Beyond this Brief Anomaly over the past year or so, that goes beyond the very brief article for The Conversation in May, but that is more accessible than the detailed documentation provided in earlier posts here, here and here. The article presented here is intended to fill that gap. It’s based on the presentation I gave in July at a University of Melbourne Carlton Connect Initiative event on energy transitions, discussed in the introduction to this earlier post. The presentation abstract will serve for orientation:
Energy transition discourse in both the public and academic spheres can be characterised by strong and often fixed views about the prospects for particular pathways. Given the unprecedented scale and complexity of the transition task facing humanity, greater circumspection may help ensure collective efforts are effective. While significant attention has been given to the question of how to satisfy future energy demand with renewable sources, dynamic effects during the transition period have received far less attention. Net energy considerations have particular relevance here. Exploratory modelling indicates that such considerations are relevant for more comprehensive feasibility assessment of renewable energy transition pathways. Moreover, this suggests there may be value in asking broader questions about how to ensure energy transition learning and praxis is sufficiently ‘fit for purpose’.Continue reading →
In the most recent posts last year, I looked in some detail at what the energy costs of energy supply imply for global-scale transition from fossil fuels to (mostly) renewable energy (RE) sources. The modelling presented there highlighted the importance of taking a dynamic view of transition – rather than just looking at the start and end states. If we’re serious about identifying feasible transition pathways, this type of approach has an important role to play. It’s reassuring to see that more significant effort is starting to be made in this area.
One reason this has been slow to gain traction is the idea that renewable energy sources are so abundant as to be without practical limits. It’s a popular and compelling story, but unfortunately, also one that obscures as much as it reveals. Here, I’ll explain why, and set out the detailed case for why we are much better served by thinking in terms of the practically realisable potential for renewable energy, rather than the raw physical flows. At the heart of this is a basic insight, expressed in a simple aphorism: ‘each joule of energy is not equal’. Continue reading →
In this post I’ll discuss further developments relating to the energy transition modelling exercise covered in detail in the previous two posts (here and here). Consistent with Beyond this Brief Anomaly‘s inquiry ethos, I view the exercise as effectively open-ended. The findings at any point in time can be considered provisional and subject to refinement or revision as learning unfolds, as new ways for making sense of the modeled situation come to light, and as the ways in which the situation itself is understood change. This particular modelling effort should not be treated as the “last word” on the subject. Indeed, the best outcome from the work would be an increased public concern for the dynamics of energy transition — leading to new initiatives that explore the implications independently, going beyond what is possible with this relatively modest foray.
Nonetheless, the findings to date from this work demand close consideration from anyone seriously committed to renewable energy transition. The essential insight is this: in the rapid build-out required for a major transition in primary energy sources, effective aggregate energy return on investment (EROI) for a replacement source’s total stock of generators is lower than for an individual generator considered in isolation. The overall EROI ramps up from zero at the commencement of the transition, only reaching the nominal value for an individual generator over its full life-cycle when the transition is effectively complete i.e. when the generator stock reaches a steady state. All of the other key findings flow from this fundamental feature of any rapid transition in primary energy source. If a replacement energy source has lower nominal EROI than incumbent sources, then this becomes a critically important feasibility consideration.
The specific model developments introduced here are summarised as follows (I’ll discuss each in more detail below):
The conversion of power outputs to energy service outputs in the form of heat and work for each supply source has been thoroughly overhauled, resulting in a far more refined implementation of this feature of the model.
Conversion of self-power demand to emplacement and operating & maintenance (O&M) energy service demand in the form of heat and work has also been modified for each supply source.
The maximum autonomy period that determines the amount of energy storage for wind and PV electricity can now be increased gradually as the intermittent supply penetration increases as a proportion of total electricity supply.
For the default parameter set (now called the “reference scenario”, previously “standard run”), the maximum autonomy periods for wind and PV supply are arbitrarily reduced to 48 and 72 hours respectively, simply for the sake of heading off any knee-jerk response along the lines that “the amount of storage assumed to be necessary is unrealistic, therefore the entire model is suspect”.
Detailed calculation is now included for levelised capital cost and O&M cost for wind and PV supply plant, and levelised capital cost for batteries (making the discussion of this in the previous post now redundant).
The updated version of the model to which this post relates is available here.
The full parameter set for the updated model’s “reference scenario” (equivalent to the “standard run” in previous posts) is available as a PDF here.Continue reading →
In this post I take a detailed look at the simulation results for the energy transition model introduced in the previous post, when it is run with the default parameter values—what I referred to last time as the “standard run”.
Before getting started though, this is a good place to reiterate the motivation for undertaking this work. I’m prompted here by a post on John Quiggin’s blog that he provided a link to as a comment on the previous post. The post is a 300 word dismissal of the relevance of energy return on investment in assessing PV electricity supply performance. It was—I assume inadvertently—a timely demonstration of the central point I was making: to have a productive conversation about these issues, we need to take a comprehensive, integrated view. But looking beyond the technical superficiality of John’s argument, he also made the misleading inference that a concern with the energetics of energy transition is the exclusive preserve of “renewable energy critics”.
With this in mind, I’ll state my position as clearly as I can here: an interest in critically assessing the capacity for renewable energy systems to directly substitute for incumbent energy systems should not be conflated with “being opposed to renewable energy”. I myself am a long-time proponent for and supporter of a transition to renewably-powered societies. Having taken the time to be fairly broadly and deeply informed in this area, it is apparent that there are significant uncertainties relating to the forms that such societies might take, especially given the tight coupling between current globally-dominant societal forms, and the characteristics of their primary energy sources. It’s apparent to me that humanity stands a better chance of developing future societies supportive of high life quality if these uncertainties are taken seriously, rather than being discounted or ignored. The question that most interests me here is:
What forms might future renewably-powered societies take, if they are to enable humans and other life forms to live well together?
And following from this, how might we best pursue the process of transition towards such future societies?
Developing a more integrated view of the relationship between societal forms and their enabling energy systems would seem to be of benefit here. I do work in this area primarily because a widespread interest in this is not apparent amongst the communities that currently dominate renewable energy transition discourse and practice. Furthermore, my own inquiry suggests that failing to take a more integrated approach as early as possible could have increasingly adverse consequences as such a transition proceeds.
And with that, it’s back to the primary task of considering what our energy transition model might have to tell us about such matters.
In the concluding section of the report made available here last month, I hinted at a view on the role of batteries in global energy supply that, in the wake of the announcement from Tesla CEO Elon Musk on 30 April this year, may seem rather at odds with prevailing popular sentiment. I suggested there that, while significant numbers of electricity consumers will likely be motivated to go “off grid” as battery costs reduce, this will entail feedback effects with implications that can reasonably be expected to make for a change trajectory far less linear and predictable than many commentators envisage. Such a view is, of course, entirely consistent with the systemic approach to thinking about energy transitions for which Beyond this Brief Anomaly advocates.
In this post, I introduce the energy transition model I’ve been developing over the past few months, to help make better sense of the physical economic implications of a global energy shift in which wind and PV generation with battery buffering dominate electricity supply. Continue reading →
In the previous post in this sequence, I developed the concept of power return on investment as a complementary indicator to energy return on investment (EROI) for assessing the viability of wind and solar PV as alternatives to thermal electricity generation. I used as my departure point for this an article in which Ioannis Kessides and David Wade introduce a dynamic approach to EROI analysis. Specifically, I drew on an illustrative example that they present, based on IEA data for coal-fired thermal and wind electricity generation in Japan, showing how the time required for coal and wind installations to provide sufficient energy to emplace additional generating capacity equal to their own can differ by an order of magnitude even where the EROI for coal and wind is identical. Given that the data on which this example was based was from prior to 2002, both the doubling time in Kessides & Wade’s example and the power return on investment in the extended analysis would likely be improved if up-to-date figures for emplacement energy and capacity factor were substituted for those from the IEA study. Unfortunately, this goes only a limited way to mitigating the central issue in terms of “real world” considerations. Continue reading →
Update, 24 July 2015: while doing some background work for a forthcoming post that draws on data presented here, I reconsidered the best basis to use for the PV comparison. The post has now been revised to reflect my updated thinking, specifically using a higher EROI for PV of 4.17:1, rather than the original of 2.45:1, by considering only a subset of Prieto and Hall’s energy costs. In the course of making this change, I also discovered an error in the original calculation, in the ratio of emplacement energy to operating & maintenance energy for PV (relatively minor impact only, from 0.59 to 0.55). This is also corrected here.
An important principle to bear in mind for inquiring into the ways that energy-related considerations influence human societies is that, by and large, economies are dependent for their present functioning not on the total stocks of energy sources they might have at their disposal, but on the current rate at which energy sources are supplied and utilised. This is a key distinction in understanding the phenomenon of peak oil. “Peak oil” for a given field or territory is taken to have occurred at the point in time for which the production rate for petroleum—appropriately defined, i.e. by grade or composition—reaches a maximum, and thereafter declines. But at such a time, as much as half of the ultimate resource may still be available. Peak oil doesn’t imply that we’re on the brink of “running out of oil”. What it means is that the production rate is at the highest level that will ever be achieved. It is the change in rate that is central for understanding the implications of the phenomenon for future social prospects, as a declining aggregate oil production rate (i.e. where a shortfall from one region cannot be compensated by increased production from others) implies greatly foreshortened prospects for further growth in the non-energy related economic activity enabled by that production, and in fact very likely implies commensurate economic contraction. The same principle applies to any resource that is ultimately stock-limited, but for which it is the supply rate upon which the present nature of the economic activity enabled by that resource depends. Continue reading →