Sweden could easily increase its production of biofuels to cover more than a third of the nation’s automotive fuel needs by 2030 by using forestry residues, a biorefinery report has said.
By utilising forest-sourced materials, such as residue from forestry operations, wood from forest grown for bioenergy and agricultural waste products, the country could increase its biofuels production ten times in the next 17 years, states the report submitted to the Swedish government.
Part of the overall analysis of how to wean the Swedish transport sector off fossil fuels and make it more carbon neutral, the report, signed by the Swedish Knowledge Centre for Renewable Transport Fuels, said the country could produce as much as 25-35 terawatt hours (TWh) of energy, while keeping within today’s “technological restrictions, and to a certain extent also ecological and economic restrictions”.
Trying to identify the most suitable production methods, the researchers looked into various factors related to different biofuel production strategies, their energy requirements and other sustainability factors. They said factors that matter most are the choice of raw materials, conversion route, location and size of production units, transport logistics and possibilities for joint production with other energy carriers or food or feed production.
“The type of biofuel matters less. For a production system to be considered sustainable, it should be energy efficient and not compete with today’s production by the forestry industry or agricultural production”, said Joakim Lundgren from the Luleå University of Technology in Northern Sweden.
Production of biofuel from forestry residues via thermal conversion was seen as the most efficient way of moving away from the dependency on fossil fuels.
Biofuel such as methanol or dimethyl ether (DME) could be produced by gasification of branches, tree tops or by-products from biorefinery or pulp and paper making. Such technology could deliver considerable greenhouse gas reduction while requiring only low external energy input and cost per unit. Wood from “energy forests” managed for the purpose of producing bioenergy also receives good marks for greenhouse gas reduction potential.
“Automotive fuels produced from energy forests via gasification or ethanol combined [with agricultural production] leads to a reduction per hectare which is about 50 per cent larger than for most fuel production systems based on traditional agricultural crops”, the report says. “If we add in initial carbon losses due to an increased use of bioenergy it still will be a better alternative in the long run than fossil fuels.”
External energy input for biofuel produced from lignocellulose via the gasification route is estimated at five-to-ten per cent, compared with about 50 per cent for bioethanol made from grains, the report states.
Finally, biomass-based waste from agricultural production could be used on a “somewhat” larger scale than today, in appropriate production systems, according to the report authors.
The report also suggests focusing on technology maturing and improvement - for example making biogas via fermentation or rot of organic waste, which could even serve as a way to recycle general household waste. Moreover, Sweden could increase its use of land unsuitable for agricultural production to grow energy crops or rapid-growth deciduous trees.