Biofuel for domestic flights: far from perfect but reduced emissions, increased recycling of agricultural waste

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Image: How Sustainable Aviation Fuel might reduce emissions. from Business Traveller

Farm waste could fuel most domestic flights by 2025

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Airline emissions hydrogen CSIRO plane aircraft - test

More than 600,000 flights between Sydney and Melbourne could be powered by fuel made from agricultural waste in 2025 if Australian industry and governments make changes to support sustainable aviation fuel, a report has found.

With greater investments, the biofuel could also power 90 per cent of all domestic flights by 2050 and significantly cut aviation emissions.

The Sustainable Aviation Fuel Roadmap report, released by CSIRO and Boeing on Thursday, also found a biofuel industry could create jobs and export opportunities in Australia, though it warned the industry would need more investment and research to reach its potential.

The study comes one week before the Jet Zero Council is due to meet for the first time and after Qantas and Virgin announced plans to use more biofuel to meet environmental targets.

CSIRO senior manager and report author Max Temminghoff said Australia was uniquely placed to meet growing demand for sustainable aviation fuel (SAF) because of its strong agricultural industry.

Aviation biofuel can be created using waste from farming, such as sugarcane, sawmill residue, sorghum, used cooking oil, canola and cottonseed.

Mr Temminghoff said Australia had enough feedstock that, if refined locally, could create 60 per cent of jet fuel needed for domestic flights in 2025 and 90 per cent of the fuel needed in 2050.

“The road map estimates that Australia is currently sitting on enough resources to produce almost five billion litres of SAF by 2025,” he said.

“That’s enough fuel to power 640,000 Melbourne to Sydney return flights on a Boeing 737.”

The agricultural waste could be turned into biofuels using alcohol-to-jet technology, the report found, or the Fischer-Tropsch process being tested in Perth.

Boeing APAC regional sustainability lead Heidi Hauf said producing SAF locally would create regional jobs and export opportunities, and reduce Australia’s reliance on foreign providers.

Alternative technologies, she said, including “battery and fuel cell-powered planes” were still too limited in their range.

“SAF offers the largest potential for reduction of aviation emissions in the near-term,” she said.

But the report identified challenges to creating a biofuel industry, including a lack of local refining facilities, competition from markets including Japan and Singapore, and limited public awareness.

The report called for new policies to support SAF creation and distribution, targets for its use, further research, and better feedstock collection and processing.

Mr Temminghoff said demand for jet fuel was expected to rise by 75 per cent in 2050, underlining the need for urgent action.

“The industry realises it’s on a bit of a burning platform,” he said.

“It needs to shift and this is going to allow us to be flying a big greener by 2050.”

Worldwide, the aviation industry has pledged to achieve net-zero emissions by 2050.

Qantas has committed to using 10 per cent biofuel to cut carbon emissions by 25 per cent in 2030 and Virgin Australia recently tested a flight using a 30 per cent sustainable fuel blend

The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018

Dedication: This paper is dedicated to the memory of Professor Ivar S. A. Isaksen of the University of Oslo, whose scientific excellence, friendship, and mentorship is sorely missed.

Highlights

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    Global aviation warms Earth’s surface through both CO2 and net non-CO2 contributions.

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    Global aviation contributes a few percent to anthropogenic radiative forcing.

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    Non-CO2 impacts comprise about 2/3 of the net radiative forcing.

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    Comprehensive and quantitative calculations of aviation effects are presented.

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    Data are made available to analyze past, present and future aviation climate forcing.

Abstract

Global aviation operations contribute to anthropogenic climate change via a complex set of processes that lead to a net surface warming. Of importance are aviation emissions of carbon dioxide (CO2), nitrogen oxides (NOx), water vapor, soot and sulfate aerosols, and increased cloudiness due to contrail formation. Aviation grew strongly over the past decades (1960–2018) in terms of activity, with revenue passenger kilometers increasing from 109 to 8269 billion km yr−1, and in terms of climate change impacts, with CO2 emissions increasing by a factor of 6.8 to 1034 Tg CO2 yr−1. Over the period 2013–2018, the growth rates in both terms show a marked increase. Here, we present a new comprehensive and quantitative approach for evaluating aviation climate forcing terms. Both radiative forcing (RF) and effective radiative forcing (ERF) terms and their sums are calculated for the years 2000–2018. Contrail cirrus, consisting of linear contrails and the cirrus cloudiness arising from them, yields the largest positive net (warming) ERF term followed by CO2 and NOx emissions. The formation and emission of sulfate aerosol yields a negative (cooling) term. The mean contrail cirrus ERF/RF ratio of 0.42 indicates that contrail cirrus is less effective in surface warming than other terms. For 2018 the net aviation ERF is +100.9 milliwatts (mW) m−2 (5–95% likelihood range of (55, 145)) with major contributions from contrail cirrus (57.4 mW m−2), CO2(34.3 mW m−2), and NOx (17.5 mW m−2). Non-CO2 terms sum to yield a net positive (warming) ERF that accounts for more than half (66%) of the aviation net ERF in 2018. Using normalization to aviation fuel use, the contribution of global aviation in 2011 was calculated to be 3.5 (4.0, 3.4) % of the net anthropogenic ERF of 2290 (1130, 3330) mW m−2. Uncertainty distributions (5%, 95%) show that non-CO2 forcing terms contribute about 8 times more than CO2 to the uncertainty in the aviation net ERF in 2018. The best estimates of the ERFs from aviation aerosol-cloud interactions for soot and sulfate remain undetermined. CO2-warming-equivalent emissions based on global warming potentials(GWP* method) indicate that aviation emissions are currently warming the climate at approximately three times the rate of that associated with aviation CO2 emissions alone. CO2 and NOx aviation emissions and cloud effects remain a continued focus of anthropogenic climate change research and policy discussions.

References

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