I was going to blog about something else today but then I read an article by Chris Huhne suggesting endless growth maybe possible. I just had to respond. We looked at the question of whether endless growth possible in our book in much more detail than I have space for here. However, to pick up on some of the general points we made that seem relevant. We wrote….
“Thermodynamics limits substitution. This criticism focuses in on the fact that there are physical limits on the efficiency of energy conversion, and these reduce our options for substituting one technology with another. The classic example of this is the idea
of the hydrogen economy.”
The first criticism I would make is based on this excerpt above, the Huhne piece took no account of the energy return on energy invested (EROEI). To give an example, you have to invest energy in building a solar panel before you get a return on the energy invested, the ratio of the two is known as the EROEI. The figure for renewables varies greatly with a lack of agreement even between studies, so for example solar PV it returns energy in the order of 2-8 over its lifetime over the energy used to make it. This is OK but is very close to stated minimum limits of a ratio 3-5 . I love solar PV and have it fitted to my house but I would therefore not suggest trying to run an industrial society solely from this technology. Luckily other renewables have much higher EROEI figures. The much maligned wind turbine has a very good energy return. Nevertheless it seems to me we will have both less energy to “play with” and how much energy each good and service takes will have to be accounted for and justified. A final point is that as we have extracted all the easy fossil fuels the EROEI ratio for coal, oil and gas has plummeted.
The second query I have over whether endless growth is possible is over the by-products of fossil fuels. The main thing that comes to mind is plastics. We wrote..
“Limits of the market and technology. How much technological substitution is really possible? If some natural resources are depleting they may not be replaceable.”
Again we have covered this in much more detail in our book and I skirted around this issue in my doctorate a bit. Using natural materials to replace all our plastic is probably not possible since we would have to use natural materials to supply bacteria to make bioplastic (this currently is most likely scenario). The land area required is enormous and there is competition even for agricultural waste products for other things.
The third downer on endless growth is that of other materials, again not mentioned by Chris Huhne. By these we mean metals. Again this is something we had a quick look at in our book. Like fossil fuels we have used all the easy to extract mineral resources up. We wrote…
“There is an estimate that 40 per cent of global energy might be required to extract metals by 2050“. 
This also assumes we are not running out of mineral resources.
The final objection to endless growth is as we wrote;
“the ‘Jevon’s paradox’ or the “‘Khazzoom-Brookes postulate’ after the economists who produced this theory. Essentially it means an increase in energy efficiency does not necessarily lead to a decrease in energy use”.
So in other words you buy an LED and use the money saved to do something else. Since everything we do takes energy…
To stand even the vaguest chance of endless growth at the very least we need to do a lot of recycling of plastic and metals, almost 100%. There was another question the article failed to deal with. Is endless growth even desirable. Something again from a Christian perspective we have had a go at looking at in our book, but that is another blog post…
1. Hall, C.A.S.; Balogh, S.; Murphy, D.J. What is the Minimum EROI That a SustainableSociety Must Have? Energies 2009, 2, 25–47.
2. Reinventing the Wheel: A Circular Economy for Resource Security, Green
alliance, 2011. This report summarises very neatly the findings and the potential
problems using a number of sources.