A deeper dive on PV ‘EROI’

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.[2] 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

What is the potential for renewable energy?

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