Guest post: Aviation ready to take off with biofuel

The aviation industry must transition its kerosene fuel from using conventional petroleum to more sustainable feedstocks, a GE engineer says.

Mike Epstein,<br />
GE Aviation" />

Note: This is a guest post. CNET News occasionally runs such pieces.

One of the compelling and challenging aspects of the current focus on alternative energy is the amazing array of technologies that are in various stages of development. Should a country, company, or individual investor place a bet on wind or solar? Batteries or fuel cells? Nuclear, anyone?

The trade-offs are endless. In the case of aviation, our path is somewhat clearer. There is no substitute for kerosene. Its physical and chemical properties have been optimized over 100 years to provide the best possible combination of energy content, density, and safety at an affordable price. We simply will not be flying on batteries, fuel cells, or nuclear reactors anytime soon. The former are too heavy to be practical, the latter too dangerous for everyday aviation use.

But clearly, our industry has a responsibility to our customers, and ourselves, to transition from kerosene (Jet-A) that is derived from conventional petroleum. We must shift to kerosene derived from more sustainable feedstocks.

Fuels that are chemically and physically different from Jet-A would cost trillions because the entire aviation infrastructure is built around kerosene. Aircraft, engines, airport fuel hydrants, interstate pipelines, trucks, etc. have all been designed, built, and capitalized around the predictable properties and economics associated with this type of fuel. Yes, there may be exceptions...we may well see a niche application flying on ethanol one day. But design engineers have carefully looked at these types of options, and the results aren't pretty.

For instance, a study by Boeing calculated a 15 percent to 25 percent increase in energy consumption using ethanol.

So where is the aviation industry headed and what is being done? The answer is encouraging. In 2008, we saw a sea change in the focus and the pace of activity. That was despite, or perhaps because of, the terribly high and painful prices in the middle of the year. But if your goal is to unplug aviation from oil (much as the electric power industry did in the 1980s), then 2008 was a very good year.

First and foremost, the above issues have led to a consensus within the industry that aviation alternative fuels must meet current standards and specifications. This sets expectations and provides a clear path to all parties involved. Whether this was technically and economically feasible had been in question several years ago.

GE's CF6 engines were used on the Virgin Atlantic flight test in early 2008--the first flight of a modern commercial jet liner using a 20 percent bio-derived fuel. Virgin Atlantic

The U.S. Defense Advanced Research Projects Agency, otherwise known as DARPA, launched a program to demonstrate the capability to convert plant and other renewable oils to specification-quality Jet-A. The program was wildly successful, and the cost of conversion appears to be on par with conventional refinery processes. Several fuel manufacturers have begun publicly talking in terms of integrating the processing of bio-derived oils with existing refineries.

The real issue then, is that the world is bio-oil limited, and DARPA and the industry as a whole have now started to work on that. Considerable focus is turning to production of these bio-oils via algae, fermentation, cellulosic, and numerous other pathways. One of the amazing aspects of the current "crisis" is that new, interesting, and sustainable ideas continue to come to the table for discussion and review. The number of companies, large and small, engaged in this work is exciting and too numerous to review in this blog. These are serious, interesting ideas that weren't around during the oil shocks of the '70s.

At GE, we are leading the industry with multiple programs and plans.

Our CF6 engines were used on the Virgin Atlantic flight test in early 2008--the first flight of a modern commercial jet liner using a 20 percent bio-derived fuel.

A Continental Airlines test completed in January will be an important component of a research report that will be submitted to an industry standards team in a few months. We obtained valuable operating and test data on our CFM56-7B engines, a workhorse on the popular 737 aircraft.

We continue to support the Air Force with qualification of 50-50 Fischer Tropsch synthetic fuel blends.

Finally, GE's Global Research team participated in the DARPA bio-oil program mentioned above. This was truly a breakthrough for the industry.

The aviation industry--my industry--is legendary for a "can do" attitude. We chip away at problems a bit at a time. Before you know it, 5 or 10 years have passed and we amaze even ourselves with our accomplishments. That's the aviation culture that transcends any one individual, company, or country.

The industry now has alternative fuels on the agenda. And if history is a guide, look for lots of modest accomplishments over a sustained period that, taken together, will transform the way we produce the fuels we use.

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Tech Culture
About the author

    Mike Epstein leads engineering activities for alternative fuels at GE Aviation. He has been with GE Aviation for 21 years and has worked in the areas of combustion, heat transfer, military systems engineering, and advanced, high-speed propulsion.

     

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