Carbon and Environmental Footprinting of World Biofuel Production Out to 2050

What is it about?

Environmental or ‘ecological’ footprints have been widely used in recent years as indicators of resource consumption and waste absorption presented in terms of biologically productive land area [in global hectares (gha)] required per capita with prevailing technology. In contrast, ‘carbon footprints’ are the amount of carbon (or carbon dioxide equivalent) emissions for such activities in units of mass or weight (like kilograms per functional unit), but can be translated into a component of the environmental footprint (on a gha basis). The carbon and environmental footprints associated with the world production of liquid biofuels have been computed for the period 2010–2050. Estimates of future global biofuel production were adopted from the 2011 International Energy Agency (IEA) ‘technology roadmap’ for transport biofuels. This suggests that, although first generation biofuels will dominate the market up to 2020, advanced or second generation biofuels might constitute some 75% of biofuel production by 2050. The overall environmental footprint was estimated to be 0.29 billion (bn) gha in 2010 and is likely to grow to around 2.57 bn gha by 2050. It was then disaggregated into various components: bioproductive land, built land, carbon emissions, embodied energy, materials and waste, transport, and water consumption. This component-based approach has enabled the examination of the Manufactured and Natural Capital elements of the ‘four capitals’ model of sustainability quite broadly, along with specific issues (such as the linkages associated with the so-called energy–land–water nexus). Bioproductive land use was found to exhibit the largest footprint component (a 48% share in 2050), followed by the carbon footprint (23%), embodied energy (16%), and then the water footprint (9%). Footprint components related to built land, transport and waste arisings were all found to account for an insignificant proportion to the overall environmental footprint, together amounting to only about 2%.

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Why is it important?

The European Union (EU) target of 20% renewables use by the year 2020 (with 10% of '‘green fuels’, principally biofuels, for transport) was seen by many analysts as being overly ambitious. Nevertheless, substantial progress has been made across much of Europe in terms of its ‘20-20-20’ policy framework. This reflects a binding target of a 20% reduction in ‘greenhouse’ gas (GHG) emissions by 2020 from 1990 levels (against a longer term target of an 80% fall by 2050), increasing the amount of energy produced from renewable resources to a binding level of 20% by 2020 and a nonbinding aim of a 20% improvement in the EU energy efficiency over the same timescale. The present results utilize the projections developed by the International Energy Agency (IEA) as part of their technology roadmap for transport biofuels). These extend out to 2050 and therefore account for the growing impact of SGB. In addition to assessing the carbon and environmental footprints associated with the IEA transport biofuel projections, the opportunity has been taken to critically reappraise the detailed way in which the individual footprint components have been evaluated. In particular, the water footprint of liquid biofuels has been determined using the recent work of Hoekstraand his co-workers (see, for example, Mekonnen & Hoekstra, 2011). That has enabled a cross-comparison of methods for calculating the environmental footprint components and thereby helping to better determine the relative shares of the different biofuel components out to 2050, including that associated with water consumption.

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