Mon 12 Jun 2017 – North America has a higher potential for the production of sustainable alternative jet fuels than other regions of the world because of its available resources but it is unlikely that switching to low-carbon fuels alone can make the necessary reductions in carbon emissions projected by ICAO to ensure the carbon-neutral growth goal after 2020, concludes a US study. Due to the high expense of alternative fuels relative to the projected low costs of offsets under the ICAO CORSIA scheme that starts in 2021 and the delayed transition from collective to individual offset responsibility, the incentive to switch is greatly reduced for an airline, particularly in the early years. The study by the International Council on Clean Transportation (ICCT) says robust policy support will therefore be needed to spur alternative fuel deployment at the scale needed to make a substantial contribution to CORSIA commitments.
International aviation greenhouse gas emissions from US and Canadian airlines increased from 36.2 to 60.2 million tonnes per year from 1990 through to 2015, and are projected to keep growing by an average 2.6% per year until 2035 – when CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation) is due to end – although lower than the predicted 4.3% global average. Under the scheme, the US and Canadian carriers will need to reduce their international aviation emissions to around 69 million metric tonnes by 2030.
North American carriers could be well positioned to develop low-carbon alternative jet fuels (AJF) from domestic feedstock supply, though their impact on emissions reductions depends strongly on the mix of feedstocks used. Fuels made from wastes, agricultural residues or energy crops will make the largest GHG reductions, whereas the impact of fuels made from food crops is more limited because of indirect land-use change emissions that undermine their GHG benefits relative to traditional petroleum-based jet fuels.
Therefore, to make meaningful GHG reductions through fuel switching, says the ICCT briefing, care must be taken to support fuels with the lowest environmental impacts. Those that offer low life-cycle carbon intensity in conjunction with high feedstock availability have the greatest potential.
Currently, the cheaper and more abundant feedstocks generally require more advanced technology and are more expensive to convert into fuel, whereas more expensive feedstocks, such as vegetable oils, require relatively little processing. For each feedstock category, a variety of conversion processes may be used to produce an AJF and some may be blended in higher concentrations than others. Overall, life-cycle analysis results suggest the steepest reductions come from utilising either wastes or cellulosic feedstocks.
There could be a substantial amount of low-carbon AJF feedstock, says ICCT, citing the US Department of Energy’s ‘2016 Billion-Ton Report’ that assessed the potential bioenergy supply in the United States towards 2040 across a variety of different economic scenarios and different feedstock price levels. The middle-price scenario projects that by 2030 there would be around 350 million tonnes of agricultural resources available, comprised of 50% energy crops, 40% agricultural residues and 10% woody crops. However, these feedstocks are highly sensitive to price, with many competing demands for biomass, notably from the road transport sector. Jet fuel only comprises 11% of US transportation fuel consumption. The supply of low-carbon feedstocks depends strongly on the price they can command in the market, while the aviation industry is highly sensitive to the fuel price.
The supply of used cooking oil and other types of waste fats that are currently being used to produce AJF by ventures such as AltAir in California is likely to be constrained in the future and only marginally increase in the period through to 2040. Nearly the entirety of the existing supply is being taken by the road transport, livestock and industrial sectors, notes a study cited by ICCT.
The annual jet fuel demand for international aviation in Canada and the US is projected to increase to around 10 billion gallons by 2035. Based on existing supply agreements between airlines and biofuel producers, only 112 million gallons of low-carbon AJF are expected to be readily available by 2025, less than 1% of jet fuel demand.
If, hypothesises ICCT, the aviation sector had access to 3% of agricultural biomass from residues and energy crops in 2035, this would translate to an additional 640 million gallons of ultralow-carbon AJF, the equivalent of displacing around 8% of North American jet fuel consumption by 2035. Assuming a carbon-intensity reduction of 80%, international aviation emissions could be abated by around 6.4 million tonnes annually by 2035, about 20% of the amount needed to meet the carbon-neutral growth target for the region.
Although in theory AJFs could deliver the remaining reductions, “extremely strong” policy support would be necessary and sustainable feedstocks diverted from other sectors, suggests ICCT, which says a valuable opportunity for policymakers exists to guide deployment towards the lowest carbon fuels at the outset before significant investments are made in higher carbon alternatives.
With the high expense of AJFs relative to the low projected cost of offsets in the near future making it unlikely CORSIA alone will drive high levels of fuel switching, the ICCT briefing makes a number of recommendations for supplementary policies that specifically incentivise AJF production in Canada and the United States, along with full life-cycle emissions accounting to ensure GHG targets are met.
Canada’s proposed Clean Fuels Program, for example, provides a solid foundation for incentivising the most effective AJFs because it uses a Low Carbon Fuel Standard (LCFS) structure that rewards fuels in proportion to their carbon intensity. An opt-in clause for jet fuels could benefit AJF producers with LCFS credits without implementing a carbon-intensity target for the aviation sector, so providing the industry with some of the benefits of the Program.
This alone would likely not level the playing field because the road sector’s demand and willingness to pay would still outcompete aviation, says ICCT, so it might be necessary to introduce a supplementary policy that sets aside some support solely for the aviation sector. A blending mandate or other aviation sector-specific target would help to create a market for AJFs in the absence of a strong value signal from CORSIA, it also suggests.
However, it concludes, when considering all the challenges, it is likely the bulk of aviation emissions reductions will be achieved through carbon offsets and efficiency improvements.
Projected impact of ultralow-carbon AJF deployment on international aviation emissions in Canada and the United States (source: ICCT):
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