The U.S. Department of Energy and the U.S. Department of Agriculture have
published the results
of the Biodiesel Lifecycle Inventory Study which looked at energy resources consumed and air, water and solid waste emissions generated by petroleum
. The intention of the three-and-a-half-year study was to provide a comprehensive "cradle to grave" environmental comparison of the two fuels in order to compare the total "lifecycle" costs and benefits of each.
It was determined that biodiesel has a total fossil energy efficiency ratio (i.e., total fuel energy / total fossil energy used in production, manufacture, transportation and distribution) four times greater than that of petroleum diesel fuel making biodiesel far more efficient in its use of non-renewable fossil fuels.
Other key findings showed that in comparison to petroleum diesel, biodiesel had:
- 78 percent lower overall lifecycle carbon dioxide
- 35 percent lower overall lifecycle carbon monoxide
- 32 percent lower overall lifecycle particulate matter
- 68 percent lower overall bus exhaust-pipe emissions of PM10 (significant in relation to respiratory disease)
- 83.6 percent lower overall bus exhaust-pipe emissions of particulate matter soot
- 8 percent lower overall lifecycle sulphur oxides
- No bus exhaust-pipe emissions of sulphur oxides
- 3 percent lower overall lifecycle methane
- 37 percent lower overall lifecycle hydrocarbons
- 79 percent lower overall lifecycle production of wastewater
- 96 percent lower overall lifecycle production of hazardous solid wastes
Analysis: It's great that such a comprehensive study has been undertaken that no one will be able to argue with due to its thoroughness and due-diligence. I'm surprised that nitrogen oxides emissions weren't mentioned which are typically held to be higher for biodiesel than petroleum diesel, but even if they are, clearly biodiesel is miles in front of petroleum diesel in terms of environmental impact. The key findings read like a Top Ten list of emissions we would all like to see reduced to zero and should be reason enough to continue to push forward the introduction of the renewable fuel. Biodiesel, it's good stuff.
[Source: The Independent]