But what if we could make utterly conventional motor fuels--gasoline, diesel and jet fuel--from wood chips, grass clippings or fast-growing cellulosic crops? That's the premise behind Los Angeles-based Rentech (Renewable Energy Technologies), which has been trying to do just that for nearly 30 years. The field is now becoming more crowded, as a variety of companies vie for effective processes that could achieve commercialization.
Rentech CEO D. Hunt Ramsbottom says his company uses the well-established Fischer-Tropsch process to convert "any carbon-bearing technology into jet fuel and diesel" (other companies are working on gasoline). Most competitors are producing these fuels only in very small quantities so far, but commercial-scale technology is on the way.
"We have the only alternative fuels approved for commercial aviation," says Ramsbottom, who adds that the company has sold Jet A fuel to some as-yet-unidentified commercial customers, and to the U.S. Air Force. Pending federal approval, the first revenue flight on biofuel will take place shortly.
Rentech is trying to turn waste streams into fuel. For instance, its Rialto, California plant, a partnership with SilvaGas Corporation, proposes to convert town-collected grass clippings into 600 barrels of diesel fuel daily, plus 49 megawatts of renewable power (enough for 30,000 homes). The diesel fuel produced will, among other things, power ground equipment at Los Angeles' LAX airport.
"We're sticking with clean diesel, jet fuel and electric power," Ramsbottom said. "The diesel market is growing, and outside the U.S. it's a more established fuel. There's also a 25 percent fuel economy benefit to switching to diesel. Jet fuel is a market niche for us--nobody else is doing it. The big issue for us is getting enough biomass in one place to aggregate."
Companies like Rentech are also helped by state goals for the use of low-carbon renewable fuels. Ramsbottom estimates that just meeting California's targets, set in 2007, will require the blending in of 75,000 to 100,000 barrels a day of renewables. "It will be a big market," Ramsbottom said. "We will need to do 100 Rialto-sized plants to have one percent of the market for biomass. And keep in mind that a single domestic airlines uses 2.5 billion gallons of jet fuel per year. The challenge is getting to scale."