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 this post I give a quick overview of recent goings on in the world of Beyond this Brief Anomaly, and then take a far more detailed look at the basis for the input values relating to PV EROI in the Insight Maker net energy return model: Prieto & Hall’s field study of utility-scale photovoltaic electricity generation for Spain over the period 2009-2011. Having spent quite a bit of time examining this source previously and in the run up to writing this post, I anticipated that the post would simply be a fairly dry technical document. For most folks, this is indeed an apt description. But for that small community aware of the controversies surrounding Prieto & Hall’s book, there’s a surprise in store. If you’re such a reader (and especially if you followed Ugo Bardi’s blog posts related to this a little while back here and here), then there’s a dramatic twist ahead. Yesterday in writing this post, closer scrutiny of Prieto & Hall’s study alongside the meta-study of PV EROI by Bhandari et al. (that I first learned about from those posts at Cassandra’s Legacy–thank you Ugo) brought to light something quite unexpected. But no spoilers — you’ll need to read on for the details.
And if anyone thinks I’m off the mark with this ‘discovery’, please weigh in to let me and other readers know. I’m really scratching my head over why this hasn’t come to light previously–it seems rather obvious in hindsight. 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 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 →
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 →