UC Berkeley researchers recently developed a technique to convert sugarcane biomass to bio-based fuel usable by aircraft.
According to findings published in the journal Proceedings of the National Academy of Sciences, the new fuel can be used for aviation while reducing the amount of in life-cycle greenhouse gas emissions. The process involves the conversion of sugars in sugarcane-derived sucrose using a combination of chemical and biocatalytic processes.
Alexis Bell — a campus professor of sustainable chemistry and a co-author of the study — said the findings’ significance lies in the researchers’ ability to use synthons as a building-block material to synthesize aviation fuel, diesel fuel and lubricants using the same process.
“It is the flexibility of this synthetic strategy that is the main contribution,” Bell said.
He said sugar has been used to produce ethanol, which can be blended with gasoline but can power vehicles for only 80 percent of the distance that gasoline can. By converting sugar to hydrocarbon instead, a higher energy density — or the amount of energy stored per unit volume — can be achieved, making the biofuel useful for planes and long-distance trucks, which use 30 percent of all transportation fuels.
According to Bell, unlike carbon emissions from fossil fuels, emissions from the biomass-made fuel are more sustainable because the photosynthesis of plants cancels them out.
Corinne Scown, co-author of the paper and researcher at Lawrence Berkeley National Laboratory, said bio-based jet fuel has to meet stringent requirements. Neither electricity nor fuel cells are practical for aircraft, which means only drop-in aviation fuel — biofuel that does not contain oxygen and is compatible with all the existing infrastructure and engines — can be substituted for the fossil fuels.
“We have to make biofuels just look like the hydrocarbon fuel we use today if we are going to successfully displaced petroleum-based aviation fuel,” Scown said.
Although biofuels could help alleviate climate change, a 2014 Intergovernmental Panel on Climate Change report stated that they raise two “major livelihood and poverty concerns,” including food price increase and dispossession of land as land is shifted from food to fuel production.
According to Scown, however, biorefinery that relies only on herbaceous biomass — such as switchgrass— is possible, meaning there may not be competition for food production or an effect on land use. A substantial amount of biomass from a nonfood plant — such as miscanthus, a type of grass — could be harvested sustainably and improve soil quality by restoring soil carbon in marginal land, Scown said.
The next step in the research, she said, includes a full cost analysis to optimize the new fuel for commercial application.
The research was a partnership between researchers from UC Berkeley, the Berkeley lab and BP. But according to a February article in California Magazine, operated by the Cal Alumni Association, BP pulled out nearly a third of its funding for 2015 and will cut more funding in the next two years.
Chris Somerville, director of the Energy Biosciences Institute, said the institute needs a minimum amount of funding to keep itself running.
“As the money shrinks, we have to let people go,” he said. “If we don’t find other funding, the institute will cease to exist.”
According to BP spokesperson Jason Ryan, BP is shifting its focus in its global biofuel business. He stated in an email that while the company believes there is long-term value in biofuel technology, the challenging external business environment is causing business units across BP to make “tough strategic choices.”
Ryan said BP will continue to pursue its interest in biosciences with a new Biosciences Research Center in San Diego and collaborate with partners in the industry and academia.
