While ethanol in gasoline remains a point of contention among automakers, ethanol producers, and the Congressman who love them, renewable diesel fuel seems to be moving quietly forward.
Late last month, the U.S. Environmental Protection Agency certified an ultra-low-sulfur diesel blend containing 35 percent diesel fuel manufactured from bioorganisms, the highest percentage ever certified by the agency.
diesel badge on 2011 Porsche Cayenne (euro spec)
The producer, Amyris, had to submit reams of data, test results, and other documentation to prove that diesel engines on the road today would not be damaged by the blend.
Because renewable diesels may have different viscosity characteristics than conventional petroleum diesel, the can change the flow properties of blended fuels. So far, most diesel makers selling vehicles in the U.S. warrant their vehicles only for 10 percent diesel (B10) or 20 percent (B20) blends.
Those addtional information included, "fuel property data, third-party testing, engine testing conducted by major diesel engine OEMs and highway validation tests," according to the company. It tested the fuel in a variety of vehicles, including passenger cars and both medium-duty and heavy-duty vehicles.
In April, Amyris received a grant from the U.S. Department of Energy to produce the fuel that would allow it to carry out some of its research.
The company uses genertically modified microorganisms that produce defined molecules--in this case synthetic diesel fuel--for use as both fuels and renewable chemicals.
Among other news in renewable diesel fuels, Audi recently completed a 1,000 journey entirely running on synthetic diesel created using natural gas as a feedstock.
Technically, the Amyris fuel is not a "biodiesel," which is defined as a blend of lipids (from vegetable oil or animal fat) and alcohol. In the U.S., the general definition says it is domestically derived from renewable oils. There's also a technical definition, as there are for both gasoline and low-sulfur diesel fuel.