A study by researchers at Lund University in Sweden found that Swedish biofuels produce between 65 and 148% less greenhouse gas emissions than gasoline and diesel, even when direct and indirect land use changes are taken into account. In the study, which looked at various types of biogas, ethanol and biodiesel, biogas from manure that came out on top.
The fuels studied were: biogas from sugar beet, ley crops, maize and waste products in the form of household waste, industrial waste and manure; biodiesel from rapeseed; ethanol from wheat and sugar beet; and ethanol from Brazilian sugar cane. Co-production of biogas and ethanol from wheat was also analyzed.
Biogas produced from manure, waste from food industries, and organic household waste were found to provide a climate benefit of 148%, 119% and 103%, respectively, compared to fossil fuels. The reason that the climate benefit exceeds 100%, the researchers explain, is the indirect effects obtained through increased recycling of nutrients reducing the need for fertilizers, and the increased recycling of organic matter to the soils.
Reductions in greenhouse gas emissions compared to fossil fuels from other biofuels included (without energy allocation):
- 71%; 80%; and 79% for wheat-based ethanol; sugar beet ethanol; and Brazilian sugar cane ethanol, respectively.
- 68% from biodiesel (RME)
- 86%; 85%; and 75% from biogas from ley crops; sugar beets (including tops); and maize, respectively.
We have calculated as fairly as possible and based on as similar conditions as possible. Our results do not indicate that biofuels produced from crops grown in Sweden currently lead to indirect land use changes, e.g. land clearance in South America or Asia. Despite this, a number of economists have claimed that it could take 50 years for biofuels to repay their impact on the climate, specifically as a result of indirect land use changes.
It is really quite uninteresting to rank different sustainable biofuels. There is room for all, and all are needed to develop alternatives to fossil fuels. The challenge today lies in simply increasing the quantity of sustainable biofuels.
—Pål Börjesson, researcher in Environment and Energy Systems at Lund University
Börjesson points out that each type of biofuel has different limitations in production volumes. In order to avoid negative effects, it is important to know where this boundary lies. Rapid and significant increases in production of biofuels from food crops could result in negative indirect land use changes, he said. “There is a limit, but we are not there yet.”
Besides greenhouse gases, environmental effects such as eutrophication, acid rain, tropospheric ozone and emissions of particles were included in the study, along with emissions from the use of biofuels in light and heavy vehicles. Direct and indirect land use changes were also studied.
(A hat-tip to John!)
Pål Börjesson, Linda Tufvesson & Mikael Lantz (2010) Livscykelanalys av svenska biodrivmedel (Swedish with English abstract and summary)