Aviation between climate change and high oil prices – the need for alternatives to kerosene
Civil aviation has enjoyed a continuous growth over the past decades and accessible air transportation has become both a fundamental of the global economy and an expectation of the public. This development is forecasted to continue for the foreseeable future but it is today facing a number of rapidly developing concerns.
This includes that aviation is currently fully dependent on liquid fuel and so, today, on petroleum.
Consequently, emissions from aircrafts, both carbon dioxide (CO2) and regulated pollutants such as oxides of nitrogen (NOx), carbon monoxide (CO), unburned hydrocarbons (HCs), particulate matters etc., contribute to global climate change and have consequences on local air quality around airports. Presently, aviation represents about 2-3% of the global production of green house gas effects. However it could increase in the next decade with the anticipated growth in air traffic.
Oil prices and security of supply, with the associated aspects of energetic dependence, constitute a second great concern. 2007 and 2008 have shown a high volatility of petroleum price and, for mid-term, there is consensus to expect further increases and a higher price level. Future crude oil production may not be able to keep pace with world demand, thereby forcing the transition to use alternative energy sources.
The combination of these concerns prompts the search for new alternatives that could possibly change the dominance of petroleum based fuels for aviation, with the double objective of controlling green house gas effects and ensuring fuel availability at an acceptable price. The European Union (EU) is committed to the development and use of all types of renewable or alternative energies which can simultaneously contribute to security of supply, sustainability and competitiveness. This has been expressed through a binding target of a 20% share of renewable energies in the overall EU energy consumption by 2020; it is also committed to implement the 10% binding target for the use of renewable energy sources in transport by the same deadline. This includes biofuels and sustainability criteria are set out for biofuels to be counted towards the 10% target and to be able to benefit from public support schemes. In this context, aviation could play a significant role, if suitability, environmental and social sustainability and the economic aspects are confirmed.
The search for new fuels in aviation
The share of petroleum derived fuels for transportation is currently higher for road transport (80%) than for air transport (12 %), but air transport is increasing faster and it follows longer cycles.
In the long term, there might be radical changes to aircraft technology. Realistically, due to the lifetime of aircraft in use this is not expected within the next 20 years, while the issue has to be solved in the next decade. In this context, specific attention should be given to compatibility of fuels with the existing aircraft technology, because it is not realistic to assume a complete fleet replacement at the same time. Consequently, the only solution appears to be new alternatives to jet fuel. Furthermore, due to environmental preservation, priority should be given to "clean" resources, such as renewable, in order to set a sustainable aircraft industry compatible with extensive air traffic. Developing alternative fuels should help to reduce a country's dependence on other nations for energy supplies and to soften the economic uncertainty of crude oil peaking, while it should help lessen global-warming effects.
It is already known that jet fuel could be manufactured synthetically from natural gas and coal or from upgrading of unconventional oil sources like oil sand and oil shale. Looking at South Africa for example, a synthetic fuel has already been brought into market and used to complement and to replace conventional jet fuel. These alternatives constitute "security of supply" fuels but don't reduce fossil resources dependence or environmental impacts. New pathways from biomass now promise to reduce CO2: "bio-jet fuel" derived from hydroprocessing of vegetable oils or a thermochemical process to give the so-called BTL (Biomass to Liquids) fuels.
The debate that has evolved in 2008 concerning first generation biofuels, in relation with food prices escalation, and land use (direct and indirect impacts), nevertheless highlights the need to carry out a full assessment of these new fuels by integrating sustainability criteria, which includes a global evaluation of their carbon balance (Life Cycle Analysis) but also a comprehensive analysis of production environmental impacts. The feedstock question appears as the central issue here.
Finally, introduction of new fuels in aviation will also be a matter of economical viability. Attention must be paid to the business case of alternative fuels and to the possible deployment scenario that could help their introduction.
The SWAFEA study
In this context, the European Commission’s Directorate General for Energy and Transport has initiated the SWAFEA study to investigate the feasibility and the impact of the use of alternative fuels in aviation in order to evaluate the potential and perspectives of new energy sources.
The goal is a comparative analysis of different options on the basis of a synthesis of the available data, and to build a vision and a possible roadmap for their deployment. SWAFEA will provide input for policy makers with information and decision elements.
The final results will be available in the first half of 2011 and an international conference will conclude the study.