Sustainable biofuels.

http://www.enviro.aero/Biofuels.aspx?gclid=CKuD5rub75cCFcYI3wodnSYNDA

One of the most exciting developments for aviation is the use of sustainable biofuels to replace the standard kerosene, or Jet-A, fuel that is currently being used

It is clear that our industry’s dependence on fossil fuels is not sustainable, and we see that with innovation, future generations of biofuels for aviation can and will be developed in a sustainable manner. Rapidly developing research shows that next-generation biofuels can be a viable energy source for aviation, and the industry expects that further investigation will develop fuels that can be mass-produced at a low cost and high yield with minimal negative environmental impacts. Importantly, the aviation industry is committed to exploring the use of biofuels that in no way compete for land or water with food supplies, which has been an issue in other sectors. Scroll down for the latest news on biofuels flights taking place around the world.
Terminology

The term ‘biofuels’ refers to a wide-range of fuels made from almost any form of recently living organic matter, as opposed to fossil fuels made of organic matter from millions of years ago. Biofuels can be categorised by type, such as bioethanol, biodiesel and biogas; and by source, such as sugarcane, maize, wheat, rapeseed, agricultural waste products and algae.
Specific requirements

Aviation requires a high-performance fuel that operates in a broad range of conditions and does not compromise safety. Furthermore, next-generation biofuels must be a direct replacement for traditional kerosene fuel (Jet-A) so that manufacturers do not have to redesign the engines and so that airlines and airports do not have to develop new fuel delivery systems, which would delay the introduction of biofuels. Currently, the industry is focused on producing biofuels from sustainable sources that will enable the fuel to be ‘dropped in’ to Jet-A1 â€“ in other words, blending biofuel with fossil fuel until enough biofuel can be produced to fully supply the industry.

Some so-called ‘first generation’ biofuels simply will not work in aircraft, such as ethanol. While 13 trillion gallons of ethanol are being used to power automobiles every year, it would freeze at the high altitudes at which a plane flies, making it non-usable for aviation purposes. Any biofuel used in aircraft would also have to be able to operate at high temperatures, have a low freeze point and be cost-competitive with petroleum-based jet fuel.
A sustainable supply

Sustainability is the key word for biofuels. In fact, some biofuels have a worse environmental performance than the fossil fuels that they are meant to replace. This is why it is important to use the most advanced biofuel production technology and the best biofuel feedstocks. Many of the ‘first generation’ fuel sources, such as ethanol (produced mainly from corn or sugarcane), have been suggested to cause food shortages in developing nations, taking valuable land and wasting water supplies.

It is important to use the most advanced biofuel production technology and the best biofuel feedstocks (images courtesy of Boeing)

The next-generation biofuels currently under advanced development for aviation â€“ such as algae and jatropha â€“ are fast growing, non-food crops that don’t take up land that would be used for food production. In fact, both of these potential feed stocks can be cultivated in some fairly inhospitable places, with much lower requirements for fresh water.
Exciting developments

One likely solution is a biofuel produced from algae, which sequesters a lot of carbon dioxide (CO₂) in its rapid growth and is able to be grown in salt water in areas such as deserts, ensuring it doesn’t compete for fresh water or valuable land. An acre of algae can produce enough oil to make 3,000 gallons of jet fuel in a year. The world’s entire airliner fleet could be powered from a cultivated area just the size of West Virginia, or Belgium. The seeds from the jatropha bush are also high oil-content which can be used for jet fuel, while coming from a plant that is not used as a food supply for anything. Investigations are also ongoing into other sources such as halophytes and certain types of grasses.

There are many experiments and trials in progress: currently Airbus, Honeywell Aerospace, UOP, International Aero Engines (IAE) and JetBlue Airways are pursuing the development of a sustainable second-generation biofuel. Meanwhile the Sustainable Aviation Fuel Users Group pledge, organised by Boeing, the World Wildlife Fund (WWF) and Natural Resources Defense Council (NRDC), stipulates that any sustainable biofuel must perform as well as, or better than, kerosene-based fuel, but with a smaller carbon lifecycle.

The table below summarises these highly significant flights:

Aircraft	Partners	Date	Biofuel	Blend
B747-400	Boeing, GE Aviation	23 Feb 08	Coconut & Babassu	20% one engine

B747-400	Boeing, Rolls-Royce	30 Dec 08	Jatropha	50% one engine

B737-800	Boeing, GE Aviation, CFM, Honeywell UOP	7 Jan 09	Algae	50% one engine

B747-300	Boeing, Pratt&Whitney, Honeywell UOP	30 Jan 09	Camelina	50% one engine

TBA	Airbus, IAE, Honeywell UOP	TBA	TBA	TBA