Day in and day out, engineers GE’s Peebles Test Operation subject jet engines to the FAA equivalent of a Tough Mudder race. From the giant GEnx to the tiny HondaJet, the engines must endure hurricane-force winds, bird strikes, heavy rain, hail, ice blasts and other extreme hardships to be certified for flight by aviation regulators. Like any endurance athlete, they consume a lot of calories to power through the course; as much as 200,000 bathtubs of jet fuel annually, or 10 million gallons.
But Peebles and other GE testing sites will soon start feeding jet engines a plant-based diet made from a gasified mix of greasewood, corn cobs and algae. The step will help GE Aviation cut emissions and allow airline customers to embrace biofuels.
Starting in 2016, GE Aviation plans to buy 500,000 gallons of cellulosic biofuel for engine testing every year for the next decade. The company has an option to scale the order up to 10 million gallons per year as testing volumes start to peak due to a massive order backlog. “Developing alternative sources for jet fuel is fundamentally good for the aviation industry and the environment,” said Mike Epstein, chief technologist leading the alternative fuels efforts at GE Aviation.
Epstein and his team have been working with biofuels since 2007. They have tested the fuels in both military and civilian engines, from a supersonic fighter jet to passenger jetliners. In 2008, Virgin Atlantic’s Boeing 747 powered by four GE CF6 engines burning biodiesel flew from London to Amsterdam. “The energy density was still not good, but it was a fantastic first step,” Epstein said. “There were a lot of critics who said that we’d never fly with biofuel and this flight demonstrated that we could. It evolved from here.” On Earth Day 2010, a Navy F/A-18 fighter jet dubbed “Green Hornet” flew at 1.7 times the speed of sound with tanks filled with a half-and-half mix of camelina fuel and kerosene.
The camelina plant is just one source for biofuel. GE engines have burned biofuels made from camelina, as well as the desert shrub jathropa and woodchips. The new greasewood-corncob-algae fuel will be produced by the D’Arcinoff Group in Texas. D’Arcinoff workers use the Fischer-Tropsch process to gasify the plant mix and turn the resulting synthetic gas into liquid biofuel. “The bottom line of our process is that it very efficiently captures and converts all carbon into fuel product,” says Michael C. Darcy, D’Arcinoff’s CEO. “The result is an ASTM-approved [American Society for Testing and Materials] fuel that can be produced in large quantity with good environmental life cycle properties.”
It will still take some time before we start flying planes powered by plants. Price and infrastructure remain sticking points. “Aircraft, engines, airport fuel hydrants, even interstate pipelines have been designed and built around jet fuel,” Epstein said. But biofuels could dramatically improve the industry’s greenhouse gas footprint, and innovative refinery companies like D’Arcinoff are working to bring fuel costs down. “We’ve started the transition,” Epstein said. “We’ve taken the first steps.”