SUSTAINABLE ALTERNATIVE FUELS FOR AVIATION

BACKGROUND

Environmental benefits gained through technological progress and operational improvements remain instrumental to limiting the impact of aviation on the global environment. However, even under the most aggressive technological and operationa assumptions, the anticipated gains in efficiency will not offset the expected fuel consumption increases, based on air traffic growth forecasts for the next 40 years. In under a decade, sustainable alternative fuels have emerged as a promising solution that can close part of this gap. When produced from renewable sources or waste materials, alternative fuels have the potential to yield substantial greenhouse gas (GHG) emissions reductions, on a life-cycle basis. Indeed, CO2 emissions from biofuel combustion can be considered as neutral, since the emitted carbon comes from biomass and will return to that same material. As a result, only the emissions induced by feedstock production, transportation, and processing have to be accounted for in a field-to tank approach. Similarly, producing fuel from industrial waste, both solids and gases, generates emissions reductions through the cascading use of fossil carbon. A major step towards the development of sustainable alternative fuels for aviation was the 2009 approval of “drop-in” fuels. This was considered as a significant breakthrough since these fuels are fully compliant with the stringent requirements for aviation fuels, preserving safety, as well as compatibility with existing systems, meaning that they can be “dropped in” or substituted for conventional fuels.

Progress In Sustainable  Alternative Fuels for Aviation

Commercial use of Alternative fuels 

The door to the first commercial use of sustainable alternative fuels in aviation was opened following two landmark approvals by ASTM1 (formerly known as the American Society for Testing and Materials) for the use of up to 50% alternative fuel blended with conventional fuel: Fischer-Tropsch2 fuel in 2009 and Hydroprocessed Esters and Fatty Acids (HEFA)3 fuelin2011. The hydroprocessing of vegetable oils and animal fats to produce HEFA fuel is a mature process which allowed the production of the first batches of biofuel for commercial flights, the use of which has multiplied since September 2011, demonstrating the viability of these fuels for aviation. As of June 2012 more than 18 airlines had collectively performed over 1,500 commercial flights that used alternative fuels, including regularly scheduled flights. Further initiatives are currently underway in all regions of the world to introduce sustainable alternative fuels into commercial aviation. Airlines and airports have entered into agreements for sustainable alternative fuels in North America, Europe, the Middle East, Latin America, South America, and the Asia-Pacific region, making this a truly global activity. The map below (Figure 1) illustrates where activities are currently taking place.

government and stakeholder Initiatives In 2006, the “Commercial Aviation Alternative Fuels Initiative”(CAAFI), founded by U.S.-based aviation stakeholders, was the first worldwide initiative promoting the development of alternative fuels for aviation. CAAFI supports the approval of alternative jet fuels by ASTM, as well as any policy actions for their deployment. It also produces tools and guidance to assist stakeholders, and it connects producers and customers to facilitate the deployment of these fuels on the market place. In addition, the United States is home to the Northwest Advanced Renewables Alliance (NARA) and Midwest Aviation Sustainable Biofuels Initiative (MASBI) regional initiatives. 

ICAO Initiatives

 ICAO Assembly Resolution A37-19 recognized sustainable alternative fuel as being part of the basket of measures needed to achieve the aspirational goals to stabilize international aviation emissions from the year 2020 onward. It requests ICAO and its Member States to participate in further work for the development and deployment of such fuels.

The Challenges

 There have been significant achievements over the last three years to support the deployment of sustainable alternative aviation fuels. However, despite this progress, the use of alternative fuels in regular aviation operations remains limited, as full commercial production of these fuels has not yet started. 

References

1 ASTM International, formerly known as the American Society for Testing and Materials (ASTM), develops international voluntary consensus standards and  plays a leading role in aviation fuel approval.

 2 The Fischer-Tropsch pathway produces liquid hydrocarbons from a synthesis gas, made up of carbon monoxide and hydrogen, obtained by the gasification of carbonaceous feedstock such as coal, gas or biomass.

 3 Hydroprocessed Esters and Fatty Acids (HEFA) are synthetic hydrocarbon fuels produced by hydroprocessing of vegetable oils and animal fats in order to remove the oxygen contained in these feedstocks.

CHANGELLES FOR THE DEVELOPMENT AND DEPLOYMENT  OF SUSTAINABLE ALTERNATIVE FUELS IN AVIATION 

Introduction

 Building on the outcomes of the ICAO Aviation and Sustainable Alternative Fuels (SUSTAF) Workshop held in October 2011, and on the discussions at nthen194th Session of the ICAO Council, the SUSTAF Experts Group was created in June 2012 to develop recommendations relating to ongoing challenges in the development and deployment of sustainable alternative fuels for aviation, with a view to supporting States and the industry in their efforts to develop and deploy alternative aviation fuels.

Major Challenges for  Commercial Deployment of  Sustainable Alternative Fuels

 Challenges

 While the availability of sustainable feedstocks and the impacts of their production in the required quantities are significant challenges for a commercial-scale deployment of alternative fuels in aviation over the long-term, overall economics appear to be the main issue in the near-term. Today, the most significant  challengeis stimulating the necessary capital investment to ramp up production.

To date, economic assessments of alternative fuels for aviation converge on a lack of economic competitiveness when compared with conventional jet fuels. This will continue during the initial deployment phase, before research and development, production technology progress and economies of scale result in production cost reductions. 

Possible Solutions

 A priority for the deployment of sustainable alternative  fuels in aviation is to create a long-term market perspective and address the initial price gap that exists with conventional jet fuel in order to initiate viable commercial production.  A first step in that direction is for States to include  sustainable aviation fuels in their global renewable energy and biofuels policies.

Operational Aspects

 In the effort to facilitate the development and deployment of alternative fuels in aviation, a number of operational aspects should not be forgotten.

AddItional Deployment Considerations

 Feedstocks

 Sustainable feedstock supply is a critical issue tied to the development of sustainable alternative fuels projects. Feedstocks are indeed a major component of the cost of alternative fuels. As such, they need to be included in supporting policies as well as in research and development efforts.

Possible Options for a Sustainable Commercial-Scale Deployment 

A significant motivator for deploying alternative fuels in aviation is their potential, if properly produced, to reduce aviation greenhouse gas (GHG) emissions and to contribute to ICAO’s goal of carbon neutral growth from  the year 2020 onward. Thus, GHG emissions over the entire life cycle of the fuels are of particular interest. 

CONCLUSIONS

 The balance between environmental benefits and the cost of deploying alternative fuels is deemed to be important to States and may currently look more favourable for deployment in road transportation. However, it is important to include aviation fuels in the alternative fuels policies of States. Indeed, aviation has no alternative to liquid fuels in the foreseeable future; unlike road transportation which has electricity or fuel cell options. The aviation industry is also keen to use sustainable alternative fuels to improve its environmental footprint.