Biodiesel is becoming more popular as a fuel because it is carbon neutral and fairly easy to manufacture.
Unfortunately, because it doesn’t contain the same amount of energy as petro-diesel, biodiesel is usually mixed with petro-diesel to improve vehicle performance. Users of the blended fuel aren’t carbon-neutral, but can cut their carbon emissions by whatever percentage of biodiesel is in the blend. Of course, if you don’t mind a slight loss in performance, you can find pure biodiesel to refuel and be truly carbon-neutral.
On the other hand, researchers are constantly looking for new ways to produce biodiesel that is closer to petro-diesel in chemistry and energy content. Performance could be maintained and petro-diesel completely eliminated. A lot of research has gone into strains of bacteria that can be tweaked to produce fuels or at least fuel precursors. Surprisingly enough, researchers in the Projects & Technology lab at Royal Dutch Shell [yes, that Shell] and University of Exeter have developed a new strain of E. Coli bacteria that generate synthetic diesel fuel.
“…by exploring this new method of creating biofuel, along with other intelligent technologies, we hope they [University of Exeter] could help us to meet the challenges of limiting the rise in carbon dioxide emissions while responding to the growing global requirement for transport fuel.” – Rob Lee, Shell Projects & Technology