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

IEA has projected the potential worldwide increased use of biofuels in the transport sector assuming successful technology development and policy measures reducing barriers to biomass deployment and providing economic incentives.

IEA’s World Energy Outlook 2006 (IEA, 2006b) develops an Alternative policy scenario that adds 55 Mtoe biofuels above baseline levels of 92 Mtoe by 2030, which increases the biofuels share of total transport fuel demand from 3 to 5%. In this scenario, all of the biofuels are produced by conventional technology, that is ethanol from starch and sugar crops and biodiesel from oil crops. Assuming an average CO2 reduction from gasoline use of 25%,[39] this would reduce transport CO2 emissions by 36 Mt.

Furthermore, according to the Beyond the Alternative policy scenario (BAPS), which assumed more energy savings and emission reductions through a set of technological breakthroughs, biofuels use in road transport would double compared to the Alternative policy scenario.

A second IEA report, Energy Technology Perspectives 2006 (IEA, 2006a), evaluates a series of more ambitious scenarios that yield biomass displacement of 13–25% of transport energy demand by 2050, compared to Baseline levels of 3% displacement. Two scenarios, called Accelerated Technology (ACT) Map and TECH Plus, assume economic incentives equivalent to 25 US$/tCO2, increased support for research and development, demonstration, and deployment programmes, and policy instruments to overcome commercialization barriers. Both scenarios have optimistic assumptions about the success of efforts to reduce fuel production costs, increase crop yields, and so forth. In the ACT Map scenario, transport biofuels production reaches 480 Mtoe in 2050, accounting for 13% of total transport demand; in TECH Plus, biofuels represents 25% of transport energy demand by 2050. These displacements yield CO2 reductions (below the Baseline levels) of 1800 MtCO2 in Map and 2300 MtCO2 in TECH Plus, with the major contributors being biodiesel from Fischer Tropsch conversion and ethanol from both sugar crops and cellulosic feedstocks; biodiesel from vegetable oil and ethanol from grains represent somewhat lower shares.

Although the report does not provide quantitative estimates of CO2 reduction in 2030, it presents qualitative information (Table 3.5 of the IEA report) that implies that 2030-levels of biodiesel from vegetable oil and ethanol from grain and sugar crops are similar to 2050-levels, but biodiesel from Fischer Tropsch conversion, a major source in 2050, plays little role in 2030 and cellulosic ethanol is also significantly lower in 2030 than in 2050. The implied 2030 potential from the two scenarios appears to be about 600–1500 MtCO2.

  1. ^  IEA cites the following estimates for biofuels CO2 reduction when used as a replacement fuel: Corn in the U.S., –13%; ethanol in Europe, –30%; ethanol in Brazil, –90%; sugar beets to ethanol in Europe, –40 to –60%; rapeseed-derived biodiesel in Europe, –40 to –60%.