The publication of the paper "The Sower's way: Quantifying the Narrowing Net-Energy Pathways to a Global Energy Transition" by Sgouridis, Csala, and Bardi, has generated some debate on the "Cassandra's Legacy" blog. In the paper, we argue that the Sower's strategy consists in using the energy obtained from fossil fuels (the seed of the past harvest) in order to build the renewable energy infrastructure (the next harvest) that will replace the old, fossil infrastructure. In other words, we argue for and we quantify a strategy consisting in not eating one's seed corn.
Among the comments received, here are some extensive ones received by Max Kummerow, together with some answers by Sgouris Sgouridis
Max Kummerow wrote:
Important ideas, of course, in this paper. A powerful image: eating the seed corn. And a real problem for the transition. Comments and suggestions for extensions:
1. Kummerow: Does it skip past or make a rational assumption about ending growth? That issue deserves more explicit treatment. Growth in global demand (if I missed this in the paper, my apologies, but missing it would mean it needs clearer exposition or more emphasis) at present rates (see my Kaya Identity paper draft) must be something like: population 1.1%+incomes (gdp/capita) 1.7% less -1.4% efficiency (E/Y) gains. That nets to 1.4% or doubling time about 51 years, or say, two doublings in a century. Or, 1,2,4 times more energy in a century. 8,16 in two centuries. I think you need some scenarios with different growth rates.
Sgouridis: The paper assumes an end of growth (stabilization) in energy demand per capita. As is also expected/forecasted by the UN to level out, this creates a stabilization in total energy demand. We intentionally and explicitly do not bring into this a discussion on economic figures/GDP. They complicate and divert the issue. What we observe is that in OECD per capita energy demand has been stagnant for a decade or more. The growth in developing countries is slowing down. It is quite logical to assume that demand for energy to provide a decent life has to eventually converge to a point. It is clear that the world cannot support a US or UAE energy lifestyle for everyone on the planet. We assume that eventually there will be of some kind. The “easy" scenario of 2000W/capita by 2100 reflects a bare minimum (see the Marechal et al 2005 reference). My expectation is that a more reasonable estimate should be around 3000W.
2. And, for the scenario where growth ends, steady state economy, no growth in population or incomes (or energy consumption/capita, almost the same thing), how does demand stabilize?
Again, since we do not talk about incomes, for all we care income can increase nominally. It just not imply a growth in energy demand / capita. I agree this is unlikely and those who expect the great decoupling are in for a surprise but the point is demand in the OECD has already stabilized and there is a lot of slack for it to go down. Developing countries can go up by a bit. This convergence means that demand per capita cannot, should not, and need not be expected to grow eternally.
3. I’m sure you are enough of a philosopher and historian to share my worry that the rational paradigm can be overwhelmed by myths. My father, Fred, has been involved in a 60 year controversy about cholesterol and transfats, a place where myths die hard as well. And there are the big ones: religious beliefs. So there are no guarantees that just because science says humanity should do something, that it will get done. The limiting resource (Julian Simon’s insight) is actually human intelligence, or maybe ethics. It’s a very scarce resource right now. I think maybe papers on science should somehow mention the failures of science as a paradigm. The gap between discovery and application is wide in climate science.
These are extremely astute observations and I am personally in agreement. I would also say that it is about ethics rather than intelligence – the whole society has been captured by a cancerous host (financial capitalism) which manages to inject pieces of its DNA individualism, greed, market fetishism and others in essentially all of us turning us into consumable walking replicas to varying extent. This is true for education, science, and . Nevertheless, all these are very difficult to discuss especially in an academic paper. A suggestion of mine for limiting resources can be found here: http://journal.frontiersin.org/article/10.3389/fenrg.2014.00008/full
4. A "limits to growth" perspective would ask: What becomes limiting when we start building SET? Your paper is about energy limits to SET. What other limits appear?
Again, I am sure you know of the planetary boundaries paper by Rockström et al. (2009)."A safe operating space for humanity. Nature", 461(7263), 472–475. GHG the nearest physical constraint but others include our handling of phosphate and the phosphorus cycle in agriculture, pollution especially from hard to crack endocrine disruptors, and a lot more.
5. It is hard to get everything into models because of complexity. Another issue is capital constraints. How many dollars?
Definitely an important point. As I mentioned in #1 and #2, we only look at the energy investment not the $ figure of it. Overall energy investment ratios stay below 10% or so for a viable transition. On the capital investment, we can do some rough estimates. According to REN21 we invested 270Billion USD in renewable energy in 2015. This comes down to roughly 2.4$/W. Now since this includes projects that were contracted in the past and projects in regions with high finance costs (e.g. Africa) there is no reason for this cost not to be around 1.5 with today’s technology (the state of the art is 1.4). So with technology advances and scale economies this should go down to around 1$/W by 2035. Since by this time we will need to build a minimum of 6 TW/year, this means an investment of say 6 T$ just for the supply side. For the batteries and long term storage and conversion (Power to liquids) the investment along with the electrification would be at least equal. So overall, 12 USD trillion per year at the peak (it will go down after) should be expected. Now we probably spend already in excess of 7 trillion for energy as fuel bills (http://www.leonardo-energy.org/blog/world-energy-expenditures estimates for 2010 are 6.4 trillion) so the order of magnitude is certainly within the realm of what is already happening – it is simply a matter of saner investment. Why waste billions just for buying up land for fracking when you can build RE? This ties in well with my energy credits proposal in #3.
6. And, has anybody noticed that phasing out coal, if I read Jim Hanson correctly will increase net climate forcing by more than a watt/m2? The sulfur aerosols from coal are a major cooling factor, reflecting solar radiation. Hansen said (2009) that net forcing is about 2 watts/m2. But that is net of 1.5 watts cooling from aerosols. So do the cumulative carbon targets account for effects of increased warming as the coal is phased out. (Short term v long term tradeoff.)
This is an interesting question but we have taken the targets as is from the IPCC WGI 2013 report. In my view, they should include the eventual effect of the sulfur aerosols but we need to check this point.
7. The key factor is cumulative carbon. I’m not clear how the graphs in this paper relate to cumulative carbon.
As discussed in #6. Cumulative carbon in each of the carbon scenarios stays within the IPCC indicated limit (I.e. 550, 1000, 1500 by 2100). There are no further emissions from fossil fuels.
8. What about technological feasibility? Can steel be made with renewable energy? Can everything be done without fossil fuels? How about making nitrogen, for example?
Nitrogen is an easy one – it is abundant and we can get to it either by liquefaction (cryogenic distillation) which is electrically driven or membranes (at lower purities). Hydrogen from electrolysis can be used instead of methane in the Haber-Bosch process. For steel, electric arc furnaces are a direct replacement alternative to CH4 driven ones. There are things that are harder than steel; some large agriculture farming equipment, and ships will need to be supported by either (limited) or power to liquids processes (can be fully renewable). There is a discussion of this but obviously not extensive.
9. Just for curiosity, what is the EROI now and after SET? Lower?
You can see the collective EROEI in the graph in the appendix. It more or less stays flat (PV goes keeps going higher, but eventually it drops).
10. Finally, I think population deserves a lot more attention. Countries like Japan, Germany, Italy are headed for big population declines (absent immigration, a big qualification). So maybe the world could reduce population. That is very cheap and feasible, requiring behavior changes and a little investment. Divergent fertility is evolving the world by “cultural selection” (Kaufman, 2010) towards continued population growth. UN 2050 estimates for 2050 have risen by 800 million between 2002 and 2015 revisions. No end of population growth in sight.
Good points all but also note that UN 2050 estimates fell between the 2010 and 2015 revisions. I think there is a tendency to reach equilibrium but the issue of cultural selection is something that I am not able to discuss.
More to chew on. You could expand this paper into a book on LTG of energy.
