Biofuels in aviation | AGÊNCIA FAPESP

Less polluting alternatives for aircraft fuel need to maintain thermal stability and good fluidity at high altitudes, says Guilherme Freire, from Embraer’s director of environmental and technological strategies (photo:Eduardo Cesar)

Biofuels in aviation

September 07, 2011

By Janaína Simões in Campos do Jordão

Agência FAPESP
– Aviation is responsible for the 2% of carbon dioxide emissions and 3% of all the types of greenhouse gases (GHGs). And these numbers could triple by 2050 if no action is taken.
The alert came from Guilherme Freire, Embraer’s director of environmental and technological strategies, in a presentation at the first BBEST (Brazilian Bioenergy Science and Technology Conference), held from August 14-18  at the Campos do Jordão Convention Center in upstate São Paulo.

According to the executive, aviation emitted 628 million tons of carbon dioxide in 2010, and emissions are projected to be between 1.2 and 1.4 billion tons by 2030, depending on a scenario of economic crisis or growth. The increase is especially related to development of the sector in emerging nations.

“In spite of increased emissions, aviation has evolved technologically to reduce them, especially in what is referred to increased fuel efficiency. If technological development had stopped where it was in 1990, the sector would be emitting 1 billion tons of carbon gas today. The sector’s global goal is to reduce emissions by 50% in 2050 compared to 2005 numbers,” he said.

Freire explained that the use of biofuel cannot require drastic changes to planes or other existing motors because of cost. “Any substantial alteration in the configuration of an aircraft or its motor generates impacts, mostly in terms of safety, which increases the price of the airplane and could make the use of biofuels unviable,” he pointed out. 

With a view to curbing cost increases, it is vital to have biofuel that can be mixed with existing fuels and that don’t need specific, differentiated infrastructure in order to be used. From the technical point of view, one of the greatest challenges is to maintain thermal stability and good fluidity at high altitudes. If not, the fuel could freeze in the tanks.

 “In other words, bioethanol and biodiesel for automobiles don’t meet the demands for aircraft biofuels. The criteria for sustainability must be reconciled on a global level,” said Freire.

He also affirmed that the diversification of raw materials for biofuel is a concern. “Not only aviation needs to be sustainable, but other segments of the industry as well. The competition between industries for biomass is a key question,” he commented.

Among applications that compete for the use of biomass, Freire identified fuel for cars, for aviation, for heavy vehicles like trucks and for the production of lubricants, fine chemical products and polymers.

Jatropha and algae

The Embraer cited the Standard Practice for Qualification and Approval of New Aviation Turbine Fuels and Fuel Additives (ASTM 4054), an international certification initiative for the first commercial aviation biofuel, which involves companies such as Boeing, Airbus, Honeywell, Rolls Royce, GE and others.
In July of 2011, ASTM certified the first process for the production of a biofuel called HEFA (Hydroprocessed Esters and Fatty Acids). In Brazil, Embraer, Amyris, GE and Azul airline make up a consortium that is developing the Direct Sugar to Hydrocarbon Process (DSHC), which is expected to be certified by ASTM by 2015.

Together with Amyris and Virent, the process uses catalytic reactions and biochemical fermentation by genetically modified organisms to produce hydrocarbon molecules for biofuel. The product is slated for testing by Azul next year.

Freire also spoke to biofuel testing already completed by airlines, such as Continental Airlines’ test in 2009 that used algae and Jatropha (a plant from the Euphorbiaceae family) as the raw material and a mixture of 50% of this biofuel in one of the engines.

Another example is that of TAM, which in November of 2010 also used Jatropha in a 50% mixture in one engine. One of the most recent in-flight tests was performed on April 1st of this year by Interjet, with a mixture of 27% Jatropha-based biofuel in one engine.

BBEST received funding from FAPESP, FAPESP-BIOEN, CNPq, Capes, CTBE, UNICA, Braskem, Embraer, BP Biofuels Brazil, Monsanto and Oxiteno. More information:



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