The aviation industry already accounts for 2% of all anthropogenic CO2 emissions and 12% of emissions from the transport sector, with flights generating 628,000,000 tonnes of CO2 every year. However, the world’s commercial aircraft fleet is expected to double in size over the next 20 years to accommodate a forecast annual increase in demand of 4-5%.1 As a result, the aviation industry is faced with the dual challenge of meeting the growing demand for air travel, while at the same time reducing the industry’s carbon footprint. As around 80% of aviation CO2 emissions are generated by flights of over 1,500 km, for which there is no practical alternative mode of transport,2 the only way to meet this challenge is to increase the efficiency of aircraft and the environmental performance of the fuels they use.
Alternative fuels, particularly sustainable biofuels, have been identified as excellent candidates to help achieve aviation industry sustainability targets. Biofuels derived from biomass such as algae, jatropha and camelina have been shown to reduce the carbon footprint of aviation fuel by up to 80%. If commercial aviation were to get 6% of its fuel supply from biofuel by 2020, this would reduce its overall carbon footprint by 5%. The Air Transport Action Group, a not-for-profit association representing all sectors of the air transport industry, has set itself the target of capping carbon emissions from aviation from 2020 through carbon neutral growth resulting from the implementation of these new fuel technologies and measures aimed at increased fuel efficiency. This should result in net carbon emissions from aviation falling 50% from their 2005 levels by 2050.3
With a view to achieving annual production of 2 million tonnes of fuel derived from renewable sources by 2020, the European Commission, in cooperation with leading European airlines and biofuel producers, launched the Biofuel Flightpath Initiative at the 49th International Paris Air Show, in Le Bourget in 2011. The initiative sets forth a range of activities for policymakers, bio-kerosene producers and the aviation industry to achieve this common goal. On a policy level, the initiative stresses the need for support policies, including stable sustainability criteria and a mix of financial support mechanisms for research, demonstration and commercial application for second generation biofuels.
The 2011 Flightpath Initiative was predated by several EU initiatives and projects with the overarching goal of improving the environmental performance of the aviation industry. The Clean Sky Joint Technology Initiative (JTI)4 was initiated in 2008 as a unique Public-Private Partnership between the European Commission and the industry. This ambitious research programme aimed to develop breakthrough technologies that would significantly increase the environmental performance of air transport, resulting in less noisy and more fuel efficient aircraft, thereby making a key contribution to achieving the environmental objectives of the Single European Sky initiative5. Another similar project, ALFA-BIRD6 (Alternative Fuels and Biofuels for Aircraft Development) was also already up and running before the launch of the Flightpath Initiative. This project aimed to identify and evaluate possible alternatives to petroleum kerosene, with a view to setting the path towards industrial use of the best alternative fuels. In December 2012, the EC launched the ITAKA project7 to look at removing barriers to the use of sustainable biofuels in aviation and contribute to the annual production target of 2 million tonnes of fuels derived from renewable sources by 2020. The project aims to produce sustainable renewable aviation fuel and to test its use in existing logistic systems and in normal flight operations in Europe.
Another FP7 project launched at the same time as the Biofuel Flightpath Initiative was SOLAR-JET8, which aimed to demonstrate an economically-viable, carbon-neutral path for producing aviation fuel, compatible with current infrastructure. SOLAR-JET aimed to demonstrate a process that combines concentrated sunlight with CO2 captured from air and water to produce kerosene. The project has resulted in the production of the world's first "solar" jet fuel from water and carbon dioxide, with the first successful demonstration of the entire production chain for renewable kerosene, using concentrated light as a high-temperature energy source. The project is still at the experimental stage, with a glassful of jet fuel produced in laboratory conditions, using simulated sunlight. However, the results are encouraging and give hope that in future liquid hydrocarbon fuels could be produced from sunlight, CO2 and water. The outcomes of SOLAR-JET have the potential to propel Europe to the forefront in efforts to produce renewable, aviation fuels with a first-ever demonstration of kerosene produced directly from concentrated solar energy.
Commenting on the SOLAR-JET results, European Commissioner for Research, Innovation and Science Máire Geoghegan-Quinn said: "This technology means we might one day produce cleaner and plentiful fuel for planes, cars and other forms of transport. This could greatly increase energy security and turn one of the main greenhouse gases responsible for global warming into a useful resource."9
Although producing syngas through concentrated solar radiation is still at an early stage of development, the processing of syngas to kerosene is already being deployed by companies on a global scale. Combining the two approaches has the potential to provide secure, sustainable and scalable supplies of aviation fuel as well as diesel and gasoline, or even plastics. In the next phase of the project, the partners plan to optimise the solar reactor and assess whether the technology will work on a larger scale and at competitive cost.
The search for new, sustainable sources of energy continues to be a priority under Horizon 2020. The Competitive Low-Carbon Energy call published on December 11 last year, which earmarked EUR 732 million in funding for this area over the next two years, includes a topic on the development of next-generation technologies for biofuels. This support, coupled with the promising results already being achieved by EU-funded projects and the need for improved environmental performance being placed on the industry by buoyant growth, guarantees an increasing role for aviation biofuels in the years to come.