Expert: Hydrocarbon Biofuels' Promise Tops That of Ethanol and Gasoline
By Scott Doggett August 14, 2009
Recent technological advances might put fuel from forest waste, cornstalks, algae and other biomass into commercial production within just a few years, a National Science Foundation program director said in a paper published today.
John Regalbuto, a chemical engineer at the University of Illinois, Chicago, and director of the NSF catalysis and biocatalysis program, wrote in Science (subscription required) that biomass-derived fuels are not far from being part of the energy mix as a replacement for gasoline, diesel and jet fuel.
"If recent technological innovations result in competitive production costs, hydrocarbons rather than ethanol will likely be the dominant biofuel," Regalbuto wrote.
Hydrocarbon fuels can be directly produced from the sugars of woody biomass - forest waste, cornstalks or switchgrass - through microbial fermentation or liquid-phase catalysis, he wrote. They can be produced by pyrolysis or gasification directly from the woody biomass. And they can be produced by converting the lipids of nonfood crops and algae.
"The resulting hydrocarbon biofuels will be drop-in replacements for gasoline, diesel and jet fuel; will give much higher gas mileage than ethanol and will work in existing engines and distribution networks," Regalbuto wrote.
Ethanol, which is produced by breaking biomass into fermentable sugars, is used in the U.S. as an additive to improve combustion, but it does not provide as much energy as traditional gasoline.
"The drawback to using ethanol as a complete replacement for gasoline ... is not only the high cost of its production from cellulose but also its lower energy density," Regalbuto wrote. "Ethanol has two-thirds the energy density of gasoline, and cars running on E85 (85 percent ethanol and 15 percent gasoline) get about 30 percent lower gas mileage."
But the ethanol industry is given heavy government incentives, including a renewable fuels mandate that calls for the use of 15 billion gallons of corn ethanol a year by 2022 and 16 billion gallons of cellulosic biofuels.
But the 16 billion gallons of cellulosic biofuels mandated by the 2007 energy law is not limited to cellulosic ethanol. It "can be met with green gasoline, diesel and jet fuel as well," he wrote.
And while some hydrocarbon-biofuel producers - such as Sapphire Energy, which is scaling up production of hydrocarbon fuel from algae - are lobbying heavily for federal incentives to commercialize the industry, others are moving forward without the assumption of incentives.
For instance, Virent Energy Systems boasts it will be able to produce gasoline by converting water-soluble sugars at a 20 percent to 30 percent cost advantage over ethanol and that it is competitive with crude oil at $60 a barrel in five to seven years.
Regalbuto is not urging subsidies or other incentives for biomass-based hydrocarbons, nor did he single out particular technologies or feedstocks as more promising than others. His point: It is worth looking at biofuels beyond ethanol.
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