Graham P Von Maltitz

Abstract: Biofuels have been promoted as an environmentally-sustainable solution to the global energy crisis, and a way to counterbalance global increases in CO2. The reality is more complex; under some circumstances biofuels can be a major environmental and socio-economic threat. The question then is: under what circumstances can biofuels be socially and environmentally beneficial? Southern Africa, and especially the southern African countries other than South Africa, have characteristics that make them potentially suited to biofuel production, including the availability of land and labour. The different sustainability aspects pertaining to a biofuels industry in the region is investigated. The paper recommends that interplay of research, policy and controls is needed to ensure that a viable biofuels industry can be established in the southern African countries, with net positive socio-economic and environmental impacts. 1. General introduction to biofuels Biofuels are proposed as partial replacements to petroleum-based liquid fuels, but unlike petroleum fuels, are derived primarily from vegetation products, i.e. biomass through a sixstage value chain consisting of: • Feedstock production the cultivation of biomass for feedstock. •Feedstock processing the harvesting, storing, transporting and initial preparation of the feedstock for conversion to fuels. • Bioenergy conversion the process of converting the feedstock bioenergy into biofuels, either by mechanical, chemical or biological means. • Biofuels transformation the transformation of the primary biofuels into the final liquid fuel products. • Fuel distribution the distribution of the produced fuels to the market. • Fuel market the end user of the fuels. Currently there are two main types of biofuels: bioethanol, which can be blended with petrol or used in modified petrol engines; and biodiesel, which can be used as a direct diesel replacement or as a blend with petroleum diesel. Bioethanol is derived from sugar through fermentation and distillation in a process functionally identical to the production of alcohol for the liqueur market (Bridgwater, 2006). Starchbased crops such as maize or sugar molasses require an additional processing step that converts the starch to a sugar. This simple and well established process is referred to as firstgeneration bioethanol production and has a long history of successful operation in Brazil, Malawi and many other countries. South Africa has used bioethanol in fuel in the past (1920s to about 1960), but presently only produces bioethanol for non-fuel purposes. So called second generation technologies are being developed that will allow lignin and cellulose to be used as a feedstock and hence enable non-food components of vegetation to be converted into fuel (van der Laak et al., 2007). Ethanol as a fuel is distinctly different from petrol in a number of aspects. Firstly, it is corrosive and requires modifications to the engine to prevent damage. It has only about 70% of the energy content of petroleum petrol on an equal volume basis and so about 30% more fuel is needed to travel the same distance, and performance is reduced. Bioethanol used as a blend of up to 10% with petrol requires no major modifications to car engines, though from the blending perspective there are technical considerations relating to octane values. Blending beyond 10% ethanol requires specially designed duel-fuel cars. Cars optimised to run on 100% bioethanol can also be built as is the case in Brazil where garages have two sets of fuel pumps, one for petrol and one for ethanol. Most car manufacturer warranties will cover ethanol blends to 10% (Intelligent Energy Europe, 2008). Biodiesel is derived from fats and oils through a process termed transesterification (Bridgwater, 2006). This process requires about 20% methanol, a potassium (or sodium) based 1 Email: gvmalt@csir.co.za catalyst and heat. Almost any oil or fat can be used though the properties of the resulting biodiesel will differ. The production process is technically simple and can operate at almost any scale, making it feasible for farmers to produce their own biodiesel. It is, however, only large scale plants that can guarantee consistent quality. In addition, large plants are needed if the more efficient chemical extraction of oils is used instead of simple, but less efficient, oil presses, thus raising the oil recovery from about 70% to about 98% (Jongschaap et al., 2007). Almost any oil seed can be used for biodiesel though palm oil is clearly the most productive on a per ha basis. The use of soybean results in an animal fodder in the form of a protein rich seedcake by-product, which, currently, is more valuable than the biodiesel itself; the overall production costs are therefore greatly reduced. A number of tree species including Jatropha curcus are being established as feedstocks, but in the case of Jatropha the seedcake is toxic and can only be used as a less valuable fertiliser or combusted as a fuel (Jongschaap et al., 2007). The properties of biodiesel are very similar to petroleum diesel though it only has about 91% to 94% of the energy on a per volume basis. It has a higher flash point making its handling safer, but tends to solidify at low temperatures. Biodiesel is a solvent for rubber compounds and any rubber based seals will be destroyed – a potential, but cheap to remedy, problem of older engines. Biodiesel has excellent lubrication properties and no sulphur, which are both seen as benefits. Biodiesel should work as a 100% replacement in older engines. In modern high-tech turbo-diesel engines, most manufacturers will not give warranties beyond a 5% blend, though some tractor manufactures are giving warranties up to 100% biodiesel (Intelligent Energy Europe, 2008).

TL;DR: For the effective uptake of ethanol, it will be necessary to address the factors that tend to discourage its use, particularly its high initial and operational cost, poor fuel quality, unreliable fuel supply, and poor stove design.

TL;DR: In this article, the authors synthesize the current knowledge about the impact of biofuel on ecosystem services and propose conceptually coherent indicators to reflect these mechanisms and offer a critical discussion of key issues at the interface of bio fuels and ecosystem services.