IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group III: Mitigation of Climate Change

4.4.4.3 Transport biofuels

Assessments for the uptake of biofuels range between 20 and 25% of global transport road fuels by 2050 and beyond (Chapter 5). The 2006 WEO (IEA, 2006b) Reference scenario predicted biofuels will supply 4% of road fuels by 2030 with greater potential up to 7% under the Alternative Policy scenario. To achieve double this penetration, as envisaged under the Beyond Alternative Policy scenario, would avoid around 0.5GtCO2/ yr, but is likely to require large-scale introduction of second-generation biofuels from ligno-cellulosic conversions. Based on ETP assumptions (IEA, 2006a), the mitigation potential of biofuels by 2030 is likely to be less than from vehicle efficiency improvements (Chapter 5; Figure 4.30).

4.30

Figure 4.30: Potential increased emissions from the greater uptake of unconventional oils by 2030 could offset potential reductions from both biofuels and vehicle-efficiency improvements, but will be subject to the future availability and price of conventional oil.

´╗┐Source: Based on IEA, 2006b. ´╗┐

Transport emissions of 6.7 GtCO2 in 2002 will increase under business as usual to 11.6 GtCO2 by 2030, but could be reduced by efficiency improvements together with the increased uptake of biofuels to emit between 7.1 and 9.4 GtCO2 (IEA, 2006a). This mitigation potential of between 2.2 and 4.5 GtCO2, however, could be partially offset by the increased uptake of unconventional liquid fuels (Section 4.3.1.4). Their potential is uncertain as, being more costly per litre to produce, they will be dependent partly on the future oil price and level of reserves. Overall then, the emissions from transport fuels up to 2030 will probably continue to rise (Chapter 5).