Most people assume that renewable energy resources can be substituted for fossil fuels, enabling society to continue the pursuit of high levels of consumption, travel, trade, "living standards" and economic growth. Lovins and the tech fix people reassure us that all we need to do is crank up technical advance and we can have uninterrupted affluence and growth while cutting ecological and resource costs to manageable proportions. No radical change is needed, let alone scrapping consumer-capitalist society.
It takes only a glance at some basic figures re the production of liquid fuels from biomass inputs to show that this vision is totally mistaken. (The detailed derivation is available at www.arts.unsw.edu.au/tsw/D74.RENEWABLE-ENERGY.html)
The best option is to produce methanol from woody biomass. The yield is likely to be methanol equivalent to about 150 litres of petrol from each tonne of input material, after the energy costs of production are subtracted.
For very large biomass production a yield of 7 dry tonnes per ha is unlikely, but will be assumed here. Some plantations average c 14 t/ha/y, and short rotation crops, such as willows, in favourable conditions can be around this yield. However world forest growth is only c 3 t/ha/y. Large scale biomass production would have to use hundreds of millions of ha, most of which would be well below the typical willow etc. yield.
If we assume the equivalent of 150 litres of petrol produced per tonne and 7 tonnes per ha, methanol can be produced at the equivalent of 1050 litres of petrol per ha per year, or 34.7 GJ/ha.
Australian per capita oil plus gas consumption is 128 GJ/y, which would require 3.7 ha., so total Australian consumption would require 74 million ha to be cropped at 7 t/ha/y, continually. Australian crop land totals only c 22 million ha, and reasonable forest only c 40 million ha. How likely is it that we can find another 74 million ha capable of 7 t/ha/y yield?
Australia has far more useable land than any other rich country. Total crop, pasture and forest area is 4.9 ha/person. For the US the figure is 2.8, for Europe 1.6, Asia .5, and for the world as a whole it is 1.4 ha/person. World population will probably rise to more than 8 billion. Productive land per person then will be c .8 ha/person, to meet all needs, include food, water, settlement, pollution absorption and energy.
If we used all the present 1.4 ha of crop, pasture and forest land per person just for biomass energy production, it would yield 48.5 GJ per person, which is only 38% of the present Australian oil plus gas consumption, (and only 20% of our total energy consumption.)
Let's take the most optimistic assumptions I have come across. Johansson assumed (In Renewable Energy, 1993) that we might find 890 million ha in the world for biomass production. (As he said, most of this would be degraded land, so 7 t/ha is most unlikely.) By 2070 that will be about .15 ha per person, and from above it would yield 5.2 GJ per yearŠthat is, 4% of the amount of oil plus gas energy now consumed each year by each Australian.
Let's put it another way; if 8 billion were to have Australian oil plus gas use via methanol 30 billion ha would have to be in plantations constantly yielding 7 t/ha. But there are only 13 billion ha of land on the planet!
By the way, energy use in Australian is growing at around 2.5% p.a, so it will be twice as great in about 30 years.
So make whatever optimistic assumptions you choose re technical fixes, energy conservation, "factor four" reductions and Lovinsian hypercars and you have no chance whatsoever of showing how liquid fuels from biomass can supply all people with anything remotely like the present rich world rates of transport etc.
If you think it can all be done by switching to hydrogen, see the detailed paper.
Light green people heroically refuse to attend to this kind of analysis, preferring to reinforce the message everyone in consumer society wants to believe, ie., that with a bit more effort to recycle and more technical advance, and more use of the magic words "sustainable development", the environment and other problems can be solved without us having to think about reducing our over-consumption, or scrapping the growth economy.
This is why I do not believe consumer-capitalist society can save itself. Not even its "intellectual" classes or green leadership give any sign that this society has the wit or the will to even think about the basic situation we are in. As the above figures make clear, the situation cannot be solved without huge reduction in the volume of production and consumption going on. This means radical and far reaching change in the direction of simpler ways, frugality, self-sufficiency, non-material pursuits and satisfactions, cooperative systems, locally self-sufficient and self-governing communities, and zero growth economies. (For the detail, see www.arts.unsw.edu.au/tsw/12b-The-Alt-Sust-Soc-Lng.html)