Ethanol and biogas use in Sweden shows a large climate benefit, resulting in between 65 to 140 percent fewer greenhouse gas emissions than petrol and diesel, even when so-called direct and indirect soil effects are included, a new research study shows.
The study from Lund University's Faculty of Engineering punctures the controversial argument against biofuels made from food crops, such as ethanol from grain, or biodiesel from rapeseed.
"It is pretty irrelevant to rank various sustainable biofuels, there is room for all fuels, and all are needed to produce alternatives to fossil fuels. The challenge today is to increase the amount of sustainable biofuels in themselves," Pål Börjesson, researcher in environmental and energy systems at the engineering faculty, in a statement.
The Lund study for the first time looks at the scope of Swedish biofuel use and has analyzed its environmental impact, both in relation to each other and as alternatives to fossil fuels such as petrol and diesel.
While initially seen as a major boon for the fight to control climate change, many have come to believe that growing these crops serves no net climate benefit. Arguments such as that the biofuels use up more resources during food production, and force land reclamation for food in other countries instead, have been shown by the new study to be false.
"According to our results, there is nothing to suggest that biofuels produced from Swedish-grown crops under present circumstances would lead to indirect soil effects, such as, for example, land reclamation in South America or Asia," he said.
The soil in developing countries is furthermore often assumed to be carbon-rich and thus a significant emitter of carbon dioxide, but the study shows no such link at current production levels.
"Despite this, several national economists insist that it may take 50 years for biofuels to repay their carbon footprint strictly due to the indirect soil impact."
Biogas extracted from manure was considered the best alternative in tests which covered biogas, ethanol and biodiesel in different variants. Biogas performed 140 percent better than gasoline and diesel and had a net carbon benefit.
However, even the weakest-performing alternative still attained twice the EU standard that biofuels reduce greenhouse gases by at least 35 percent compared with fossil fuels.
Each type of biofuel has different restrictions in production volumes, he added. In order to avoid adverse effects, it is important to know what those limits are.
"In the future, we could have adverse indirect effects on the land if we sharply increase biofuel production from food crops very quickly," said Börjesson. "There is a limit, but we are not there today."
Biogas from sugar beets, grass, maize, including residue in the form of household waste, industrial waste and manure, biodiesel from rapeseed, ethanol from wheat and sugar beets, as well as sugar cane ethanol from Brazil were studied. A co-production of biogas and ethanol from wheat was also analyzed.
In addition to greenhouse gas emissions, environmental impacts such as eutrophication, acidification, tropospheric ozone and particle emissions were also included in the study, as well as emissions from the use of biofuels in light and heavy vehicles. Direct and indirect soil effects were studied.
Currently, biofuels made from Swedish raw materials and sugar-cane ethanol imports account for about five percent of total fuel use in Sweden. (The Local)