The Airlines:Biofuel blenders for now?

It could be decades before airliners take on the batwing, low-drag, flying-wing look in order to achieve real gains in fuel efficiency. Those planes aren’t even on the drawing boards.
It could be more than decade before aircraft manufacturers give up jet engines, as we know them, and revert to propellers to save as much as half the fuel now consumed by turbo and fan jet engines.
It may take more than a decade for enclosed ducted fan jets – now the norm for engines hanging from the wings of the world’s airliners – to be replaced, if at all, with open rotor jets proven in the 1980’s and now being tested again.
The price of fuel or mandated cuts in greenhouse gas emissions will either speedup or slow the introduction of all the above time-tested technologies.
Electric propulsion engines powered by fuel cells or batteries are possible now for small airplanes but not for passenger aircraft any time soon.
We could probably build a network of energy-efficient, low-carbon, high speed rail lines to replace intercity air travel is less time than it would take to replace whole fleets of airliners that ply the same routes.
So, for now, in the short term, the only choice for twin goals of independence from imported oil and reduced emissions is renewable, carbon-neutral biofuels.
In a test flight Air New Zealand has now flown a Boeing 747 for two hours with one of its four engines operating on a biofuel blend of 50:50 jatropha and Jet A1. (A Boeing 747 can lose up to two engines and still remain airborne had the biofuel engine failed.)
The fuel was developed by Terasol Energy based in Chennai, India with offices in Brazil and the United States.
Aside from determining whether the energy content of the fuel was enough to provide ample thrust, the test looked for lubricity of the fuel and certainly other characteristics such as viscosity at low temperatures. Air temperature decreases at a rate of about 3 degrees F for every 1000 feet of altitude. A balmy 80 degree day can be 20 below 7 miles up, plenty cold enough to thicken untreated bio oil. (The test fuel was certainly treated.)
This test is one of many, for sure. The real test (without me on board) would be a long distance run with all four engines running on the biofuel blend.
04/01/09 Bruce Mulliken/Green Energy News

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Categories: Foreign Jan 2009, New Jan 2009