|June 15, 2007|
A Greener Jet Fuel
(This article includes extracts from the MIT Technology Review with links to the original document.)
Designing less-polluting new jet fuels is a challenge. Such a fuel must have a freezing point low enough to withstand high-altitude temperatures and an energy density high enough to allow planes to fly long routes without added weight--two requirements that take currently available biofuels out of the running. Ethanol has a low energy content and other problematic properties, and biodiesel's freezing point is too high.
Aircraft are responsible for around three percent of global carbon dioxide emissions. But emissions of nitrous oxides (NOx) and the formation of condensation trails (contrails) from water vapour at near stratospheric levels where commercial jets fly mean that the actual impact on global warming is much higher -- possibly as much as 9 percent.
The industry has been put in the spotlight, and there is a push for technological and policy solutions to improve emissions performance. Over the past year, airlines, aircraft manufacturers, and governments have initiated significant actions to address the sector's contribution to climate change.
A new biofuel under development by Amyris Biotechnologies, a startup based in Emeryville, CA, could fill that hole. The company's approach is to engineer the metabolic system of microorganisms to create a variety of specialized hydrocarbons. To date, the company has successfully created microbes that can pump out the precursor for a crucial malaria drug called artemisinin.
Spurred by interest from the British megaconglomerate Virgin, which has recently launched a fuel division, Amyris has put a new focus on a cost-competitive jet fuel. Amyris scientists say they can now produce hydrocarbons with properties that rival the current jet-fuel industry standard, a kerosene-based product known as jet-A. The microbial factories ferment sugar to produce hydrocarbons, a process that has significantly less impact on global warming than traditional fuel production.
Amyris CEO John Melo, formerly president of U.S. Fuels Operations for British Petroleum, spoke with MIT Technology Review about the company's progress.