Anaerobic digestion of food waste could double Sweden’s biogas production and reduce environmental damage by cutting methane emissions from landfill suggests a government strategy.
Swedish government agencies representing energy, agriculture and the environment have made a strong case for large societal benefits from using household rubbish and food waste from restaurants as a source of energy. Exploitation of such waste as a feedstock for biogas production would cut the quantities going to landfill and associated global warming-inducing methane emissions.
The need to boost industrial competitiveness through more efficient materials use and to reduce the fossil-fuel dependency of Sweden’s energy sector lay behind the proposals. Power production and heating offer the greatest potential for biogas, although it is also a valuable alternative to petrol and diesel in some local transport cases. The problem for transport is the need to build an expensive distribution network for large volumes of the gas.
Sweden is focusing on production as there has if anything been too much stimulation of demand for biogas. The strategy concentrates on supply, which needs to be increased to keep up with demand. While setting no hard targets, it suggests about half of all household garbage and restaurant food waste could be used for biogas production, enabling Sweden to double its production of biogas from 1.5 to 3 or 4 TWh/year – still only about 1% of the country’s total energy use.
Biogas should however compete on an equal footing with other plant-based energy sources. Hence, no economic incentives are proposed apart from for manure. There already exists a more general taxation system promoting all biomass.
Proposed research priorities are to increase the effectiveness of small-scale biogas production plants and to give economic value to the solid by-product generated during the process. This has potential as fertiliser, but must be cleaned as it can contain poisonous metals for example if the feedstock was sewage sludge. The strategy also foresees the development of the gasification of forest waste and producing biogas from algae.
Regulatory changes recommended include a reduction in tariffs for biogas producers to access the electricity grid: a high proportion of the profit in biogas production currently goes to network owners in the form of such tariffs, leaving biogas producers with less of an economic driver to develop their product.
At EU level, the European Parliament has called for a Directive setting biogas production targets, incentives for new installations and quality standards for biowaste. But the European Commission ruled out legislation on biowaste in May after concluding that there are no policy gaps at EU level that new laws could fix. Member States had questioned the viability of EU standards due to different local circumstances. Germany dominates biogas production in Europe, largely due to its feed-in tariffs and supportive banking sector.
A biogas roadmap for Europe:
http://www.aebiom.org/IMG/pdf/Brochure_BiogasRoadmap_WEB.pdf [3 MB]
European Biogas Association: