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Research Report

Technologies to produce liquid biofuels for transportation: An overview

Hannes Schwaiger
Naomi Pena
Aline Mayer
David Neil Bird
Copyright Date: Jan. 1, 2011
Pages: 32
OPEN ACCESS
https://www.jstor.org/stable/resrep02307
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Table of Contents

  1. (pp. 1-1)

    Mandates and incentives to drive greater use of biofuels for transportation are being adopted in both developed and developing nations. Greater production and use of biofuels is being promoted to improve rural living conditions, reduce reliance on imported petroleum and mitigate climate change. For developing countries, increased income from exports and accompanying opportunities to improve social and employment opportunities are also important goals.

    These mandates and incentives are needed to drive biofuel production because, with the exception of Brazilian sugarcane-based ethanol, all biofuel production pathways currently result in fuels whose costs are higher than those of petroleum-based fuels (at prevailing...

  2. (pp. 2-4)

    This overview, focuses primarily on first generation means to produce biofuels: ethanol through fermentation of plant sugars and sugars derived from starches, and biodiesel through transesterification of oils from seeds. While no classification scheme is universally accepted, in general, second generation avenues are characterised by higher costs, greater risks, and technological hurdles. Thus, with a few exceptions, second generation avenues are less likely to be suitable for developing country investment.

    Ethanol is the leading biofuel used today. In the United States it is primarily produced by fermenting sugars in corn starch and in Brazil primarily from sugarcane. In 2009, the...

  3. (pp. 5-8)

    Countries around the world are producing feedstocks for biofuels. Preferred feedstocks depend on country circumstances, including climate and soils, trading opportunities, traditional and current crops, and land uses. The following subsections provide an indication of the feedstocks being produced in various countries and the variation in yields, both per hectare and per litre of fuel.

    As shown in Table 3 and Table 4, the primary feedstocks for ethanol are corn and sugarcane; and for biodiesel are soya, rapeseed and oil palm. With the exception of China, developing countries are using sugarcane as a feedstock for ethanol. Oil palm is the...

  4. (pp. 9-11)

    Brief descriptions of key crop materials used, or foreseen, as biofuel feedstocks are provided below. The descriptions start with first generation plant materials, divided into those used for ethanol (sugars and starches) and those used for biodiesel (oils). Plants that are second generation but convertible with first generation technologies are covered next, followed by materials that require second generation technologies.

    All first generation feedstocks have both the advantage and disadvantage of being used for food and biofuel. The primary disadvantage is that use of these crops for biofuels competes with food demand. The advantage is that farmers gain some protection...

  5. (pp. 12-15)

    Conventional ethanol processes convert sugars to ethanol (C2H5OH), through yeast-based fermentation. Fermentation with yeast has been used for centuries if not millennia all around the world. In the case of starches, enzymes are used to break the starches down to simple sugars in a process called hydrolysis to enable the fermentation process. Once the ethanol is produced it must be distilled.

    Both fermentation and distillation require heat. In the case of sugarcane-based ethanol, cane residues (bagasse) supply the heat. Since bagasse is a biomass energy source sugarcane- based ethanol has very low GHG emissions. In the case of corn-based ethanol,...

  6. (pp. 16-17)

    Figure 11 illustrates the costs of ethanol and biodiesel from current pathways. While other sources provide cost estimates differing from those shown, sources generally agree that the lowest cost biofuel option is sugarcane-based ethanol from Brazil. Ethanol costs in India are similar to those shown for China (i.e. around €0.4/litre) (Feller 2007). Production costs for biodiesel generally fall in the range of the higher cost sources of ethanol, except where waste vegetables oils are used as the feedstock. Johnston and Holloway (2007) estimate biodiesel costs of €0.4/litre for Malaysia and Indonesia and €0.5/litre in India and South Africa.

    When considering...

  7. (pp. 18-19)

    For developing countries interested in producing feedstocks or biofuels for export, the magnitude of fuels imported, as well as primary importing countries, will be important. As Figure 13 shows, trade in biofuels is, and is expected to remain, a small fraction of production.

    Table 5 shows that Brazil, a major ethanol exporter, has been exporting more ethanol to India than to the United States, with exports to South Korea, Sweden and the Netherlands also significant....

  8. (pp. 20-20)

    Since GHG reductions are important to both Europe and the United States, biofuels with low GHG profiles will be important to the extent that these are desired markets. Evaluations of the GHG savings of biofuels vary widely due to differences in assumptions regarding the multiple factors that contribute to GHG profiles. Assumptions include fertiliser use, productivity per hectare, machinery used in cultivation and harvesting, land use change, and conversion process fuel and efficiency. An important factor in a biofuel’s GHG profile is whether GHGs are split between a biofuel and its co-products, if any. If so, attributing part of a...

  9. (pp. 21-21)

    The production of liquid biofuels is seen as one option to mitigate global climate change by substituting a renewable resource for fossil fuel based transportation fuels and thereby reducing GHG emissions. Partly for this reason, and partly due to interests in energy security and support for rural areas, mandates and incentives to drive greater use of biofuels for transportation are being adopted in both developed and developing nations. For developing countries, increased income from trade and exports are also important goals. However, particularly due to carbon dioxide emissions caused by land use change driven by new biofuel production, the effectiveness...