Aviation biofuel

Aviation biofuel is a biofuel used for aircraft. It is considered by some to be the primary means by which the aviation industry can reduce its carbon footprint. After a multi-year technical review from aircraft makers, engine manufacturers and oil companies, biofuels were approved for commercial use in July 2011. Since then, some airlines have experimented with using of biofuels on commercial flights. The focus of the industry has now turned to second generation sustainable biofuels (sustainable aviation fuels) that do not compete with food supplies nor are major consumers of prime agricultural land or fresh water.

Aviation's share of the greenhouse gas emissions is poised to grow, as air travel increases and ground vehicles use more alternative fuels like ethanol and biodiesel. Currently aviation represents 2% of global emissions, but is expected to grow to 3% by 2050. In addition to building more fuel efficient aircraft and operating them more efficiently, changing the fuel source is one of the few options the aviation industry has for reducing its carbon footprint. While solar, electric and hydrogen propelled aircraft are being researched, it is not expected they will be feasible in the near or medium term due to aviation's need for high power-to-weight ratio and globally compatible infrastructure.

Biodiesel that is stored for long periods of time is more likely to oxidize, especially at low temperatures, causing it to gel. Some additives improve the cold weather tolerance of biodiesel, but only by a few degrees.Nitrile-based rubber materials expand in the presence of aromatic compounds found in conventional petroleum fuel. Pure biofuels that aren't mixed with petroleum and don't contain paraffin-based additives may cause rubber seals and hoses to shrink. Manufacturers are starting to use a synthetic rubber substitute called Viton for seals and hoses. Viton isn't adversely affected by biofuels. The US Air Force has found harmful bacteria and fungi in their biofueled aircraft, and use pasteurization to disinfect them.

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