How much energy does biodiesel provide, compared to the amount of fossil energy it takes to make biodiesel?
This “fossil energy ratio” has been calculated most recently (as of 2011) to be 5.54. In other words, biodiesel provides 5.54 times more energy than the fossil energy used to make it.
Compare this to the energy ratio of petroleum, which has been calculated at .83 (see page v of the 1998 USDA study). In other words, it takes more energy to extract and transport petroleum than the energy in the petroleum itself.
The links on this page provide more information on biodiesel energy balance.
- Latest study: Biodiesel yields 5.54 times the fossil energy used to make it — This latest energy life cycle analysis was published in 2011, and uses 2006 data.
- Webinar on biodiesel fossil energy ratio – July 21, 2011 (50 minutes long)
- Life Cycle Analysis of Soybean Biodiesel — This two-page Tech Note gives a general explanation of energy life cycle analysis.
- Biodiesel Energy Balance — This 5-page article is rebuttal to a 2005 article by Pimentel and Patzek which claimed that biodiesel had a negative energy balance.
- Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus — This USDA study, done in 1998, was the first comprehensive life-cycle assessment of biodiesel.