Biofuels.

Proposed solutions to the global warming/CO₂ problem fall into three categories, which might be called Abstinence, Low-Tech and High Tech. Abstinence-based solutions require major changes in the Western way of life in order to cut carbon emissions to a minimum. At the other end of the scale, High Tech solutions require carbon-based technology to be replaced by some completely new, centrally planned (and very expensive) infrastructure, such as nuclear power or hydrogen fuel, so as to preserve the same way of life almost unaltered. The use of biofuels to cut CO₂ emissions lies somewhere in between, but nearer to the High Tech end of the spectrum.

The concept behind biofuels is that the carbon which is released as CO₂ when a plant is burned was taken out of the atmosphere by the plant during its life, so it is just being recycled. Fossil fuels (coal and oil), which lived in the distant past, do not of course play this role. If you can find the fastest-growing plant possible, the more quickly you can store carbon in the plant and then burn it.

To be helpful, the plant is transformed into a product which can be put to burn in our cars and power stations. This is usually done by fermenting plant sugars to yield everybody's favourite reduced straight-chain alcohol. The common sugar-yielding plants – canes, grains and beets – are inefficient sources for various reasons. However most plants contain other forms of sugar in their cellusose. If we could access this, it would make biofuels more attractive than the current cane and grain dominated programmes.

A major problem has recently arisen with the biofuel concept. The past year has seen steep rises in food prices world-wide, at the same time that global food reserves are near record lows (and falling at a record rate). There is widespread agreement that land being taken out of food production for conversion to biofuels, under the influence of government subsidies, is contributing to the problem.

The deleterious effects of biofuels arise largely in the way the two biggest programmes work, those of Brazil and the U.S.A. It is worth noting that neither of these programmes is mainly intended to reduce carbon emissions. The Brazilian programme goes back about 30 years and was begun purely in the interests of economic development, exploiting Brazil's long-established sugar cane harvest and bringing jobs to the impoverished North-East. The American program uses a very unsuitable plant (maize), because its main aims are to reduce dependence on imported oil and to subsidize Mid-Western farm voters.

Problems with ethanol from sugar cane

The problems with the sugar-cane approach occur basically in one country, Brazil, though other Latin American states are potential producers. It is important to note that Brazil regards itself as a developing country with diminished reponsibility for climate change, nor do they accept any international responsibilities for the important Amazon ecosystem. During 30 years of experience, they have gone a long way towards solving, not just the technical problems of obtaining ethanol, but of building an infrastructure – an ethanol economy – to exploit it. For example the waste from ethanol production, or “bagasse”, is consumed in combined heat/power plants (CHP) in situ.

The Brazilian sugar cane crop for biofuel use occupies about 7% of the country's agricultural land, and about the same again is used for sugar for food. Both areas are expanding rapidly. Sugar for food has not seen the large price increases which cereal food crops have undergone in the past year, and it does not appear that the biofuels programme is directly replacing the food crop. However, Brazilian government plans to double the total sugar crop within 8 years might lead to food-fuel land use conflicts¹.

It remains possible that the Brazilian government subsidies for biofuels are discouraging food production indirectly, by encouraging growers to switch to sugar cane. This seems unlikely to be happening with wheat and rice, the production of which in Brazil is not falling, and which only grow in the far south of the country for climatic reasons. Subsidies might also be encouraging a “double displacement”, whereby land in the North is converted to sugar cane, displacing other crops which can grow in the Amazon basin, unlike sugar. The activities most likely to be displaced to the Amazon zone are soybean cultivation and grazing of cattle, both of which have been implicated in deforestation.

It should be noted that this double-displacement process will happen whatever Brazil chooses to do in the North-East (ethanol or otherwise). It is in fact a result of the world food crisis, not a cause of it, insofar as it is driven by high prices for the displaced products (rather than, say, population pressure in Brazil).

Problems with ethanol from corn (maize)

If Brazil's use of sugar cane for ethanol production appears relatively benign, this is far from true of the other big programme, America's rapidly increasing use of corn. In fact, it would be difficult to think of a worse-conceived biofuel program. In terms of area efficiency, energy efficiency and carbon savings, corn comes out far worse than sugar cane.

The U.S. program of subsidies for corn ethanol has definitely been one of the major factors in the increase in food prices. The impact of corn ethanol on prices is not denied, but lauded, by its advocates:

Ethanol production makes huge amounts of the nation's corn disappear...affects overall corn supply and helps shore up corn prices nationwide...[It] adds 30¢ to the value of a bushel of corn”²

It is generally agreed that the conversion of food cereals to corn, and of corn for animal feed to ethanol, is reponsible for at least 30% of the increase in food prices [IFPRI]. The rest is due to commodity speculation³, new sources of demand in Asia, and perhaps to the oil shock [FAO]. The fact that the U.S. ethanol programme has been implemented extremely rapidly cannot have helped matters.

Instead of food prices, I will concentrate here on the ecological side of America's corn ethanol programme – can it deliver a clean energy solution without too much environmental cost? Corn- growing in the U.S. has developed in a very labour- and resource-intensive way, and many of its characteristics are environmentally undesirable:

• Chemical fertilizers are used more intensively than any other crop, which cost energy to produce

• The U.S. style of farming is operationally very wasteful of energy, being heavily mechanized and requiring energy inputs for fuel, machinery, infrastructure etc.

• Irrigation is used on about 15% of the crop, costing energy for pumps

• The growing season is only 120 days/year and there is only one crop per year

• The seeds are produced by a very labour- and energy-intensive breeding process

• The leftover plant parts (“stover”) must be ploughed back into the soil to replace lost nutrients, and cannot be used for CHP.

Among the energy inputs, about 40% comes from fertilizer and insecticides, another 40% from operations, and 20% from the seed hybridization process. When these inputs are taken into account, the energy efficiency of the corn ethanol programme is found to be very marginal – different authorities come up with different numbers, but they are all close to 100%, and the most recent calculations come up with numbers closer to 90%⁴.

100% here means that you only get out as much energy as you put in. In other words the corn ethanol programme appears to consume more energy than it produces. By contrast, the Brazilian sugar cane ethanol programme has an energy efficiency of 500 to 600%.

Second generation biofuels

Second generation biofuels are not obtained from the energy-storing (starch and sugar) part of the plant, but from the cellulose, which also contains sugar, but in a form which is much more difficult to ferment to ethanol. Most plants produce cellulose, so if one had a way of extracting ethanol, one could choose a much more suitable crop to plant than maize. Grasses (switchgrass, miscanthus) are favoured in the U.S. because they are especially rich in cellulose, but Japan has already gone ahead with production of ethanol from wood waste.

In principle this would ease the food-fuel conflict, being less demanding of arable land. However, cellulose is rigid and requires to be broken down before processing, which requires a great deal of energy. As with maize, the energy equation may turn out to be unfavourable. It is not yet clear which feedstock will turn out to be most efficient, or which of the various processing methods will be favoured. The method is at the experimental stage, and requires heavy government subsidy.

Conclusion

I regard the U.S. programs – corn/ethanol and second-generation – as being what I called earlier High-Tech, mainly because that is the nature of all agriculture in the United States. The Brazilian sugar cane programme is closer to “Low Tech” - small scale, gradual, integrated into a new style of economy (the “ethanol economy”), rather than trying to preserve the existing (unsustainable) economy. The costs of the U.S. programme are now openly visible in high food costs, but it always had hidden energy costs which made it a poor model to follow, and I would suggest that this is true of High Tech approaches to all environmental problems.

 

1 Sugar cane total production is projected to go up 80% (270 to 495 Mt/yr, 2008-2016), as it has done in the earlier 9-year period (170 to 270 Mt/yr, 2000-2008). Ethanol rose proportionately in 2000-2008 (13 to 23 Gl/yr) but will rise slightly more in 2008-2016 (23 to 44 Gl/yr, 90%). The balance between food vs. fuel is unlikely to change much – if all goes according to plan [OECD].

2 National Corn Growers Association, “Ethanol and Coproducts”, http://www.ncga.com/ethanol/main/economics.htm, 2005. Note that at that time the basic price of corn was $3/bushel.

3 Including speculation in maize itself, which may have caused at least a further 30% rise [World Bank].

4Critical Reviews in Plant Sciences, Vol. 23, No. 6, p. 519, 2004, and Thermo-dynamics of the Corn Ethanol Biofuel Cycle, http://petroleum.berkeley.edu/papers/patzek/CRPS416-Patzek-Web.pdf, 2006.

 

“Prince Charles's 38-year old Aston Martin now runs on 100% bioethanol made from surplus English wine” - Yahoo news 20080630.