Sustainable and cost-effective fuels for aircraft
The EU is committed to minimising dependence on fossil fuels for energy. Alternative forms of energy will decrease greenhouse gas (GHG) emissions and climate change, and contribute to energy security and cost stability. Most efforts to find renewable and environmentally friendly alternatives to fossil fuels have focused on ground-based systems including both mobile (cars and buses) as well as stationary (houses and other buildings) applications. Scientists initiated the 'Alternative fuels and biofuels for aircraft development' (ALFA-BIRD) project to develop such alternatives for the aerospace sector. The multidisciplinary consortium is addressing the main challenges to using biofuels for air transport. These include the capability of operating under very cold flight conditions and compatibility with current civil aircraft given that their operational lifetimes are approximately 50 years. Four fuels have been selected for second phase testing on engine components. Short- to mid-term solutions are a fully synthetic jet fuel (FSJF) and a synthetic fuel produced from the Fischer-Tropsch process based on synthetic paraffinic kerosene (FT-SPK). Blends of FT-SPK with 50 % naphthenic cut or 20 % hexanol (oxygenated fuel) are being evaluated for the mid- and long-term solutions, respectively. Scientists assessed fuel characteristics, production, storage and distribution. They also conducted lab-scale tests to evaluate ability to produce the biofuels in a way that meets aerospace constraints and with yields compatible with up-scaling for industrial production. Detailed studies were then carried out to assess the suitability of the fuels for aircraft. Scientists tested injection and combustion properties. They also investigated compatibility of engine parts with which the fuel comes in contact, as well as effects of biofuels on air conditioning systems. Finally, investigators addressed new standard requirements of biofuels related to emissions and engine performance, and conducted a comprehensive economic analysis. The latter covered not only scientific and technical considerations, but also the economic impact related to policies and meeting regulations. ALFA-BIRD is expected to have important impact on the sustainability and competitiveness of the EU aerospace sector. In addition to assuring economic, eco-friendly and safe air transportation, ALFA-BIRD results should inspire a new air transport model for the long term.
