May 25 2010
For the first time, researchers have taken an overall look at Swedish biofuels and analysed what impact they have on the environment, both in relation to one another and to the fossil fuel alternatives petrol and diesel. The results show that they produce between 65 and 140 per cent less greenhouse gas emissions than petrol and diesel, even when direct and indirect land use changes are taken into account. Thus the report pokes holes in a controversial argument against biofuels produced from food crops, e.g. ethanol from cereals or biodiesel from rapeseed.
Some claim that these do not have any climate benefit because they crowd out food production and so force new land clearance for cultivation of food in other countries instead. The land in these countries is often presumed to be carbon rich and therefore presumed to release a lot of carbon dioxide. However, there is no evidence of such a connection with the current production levels.
"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", says Pål Börjesson, researcher in Environment and Energy Systems at Lund University, who is responsible for the report.
In the study, which looked at various types of biogas, ethanol and biodiesel, it was biogas from manure that came out on top. It produced results that were 140 per cent better than petrol and diesel and therefore was more than climate neutral. However, even the alternative that came out worst still performed twice as well as the EU directive stating that biofuels should reduce greenhouse gas emissions by at least 35 per cent compared with fossil fuels.
"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", says Pål Börjesson.
He 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.
"In the future we could see negative indirect land use changes if we increase production of biofuels from food crops very rapidly and significantly. There is a limit, but we are not there yet", explains Pål Börjesson.
The fuels that have been studied are: 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 analysed.
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.
Explanation of terms:
Direct land use changes mean that, for example, annual biofuel crops are grown on previously grass-covered pasture land, which leads to increased carbon dioxide emissions because the carbon that was previously in the ground is now released into the air. When only grass grows on the land, the carbon remains in the ground. Therefore there is a link to the same cultivation area. On the other hand, indirect land use changes do not entail the same link to a specific cultivation area. Instead, it is presumed that increased cultivation of wheat for ethanol, for example, inevitably leads to indirect emissions, as new pasture land is cultivated somewhere else in the world.
Biofuels are fuels produced from renewable raw materials in the form of biomass. Today, biomass made from Swedish raw materials and imported ethanol from sugar cane represents around five per cent of the total fuel used in Sweden.