Anaerobic digestions expands biogas benefits, says Swedish study

Wiki Commons

Publish date: September 17, 2010

A policy paper entitled "Proposal for a multidisciplinary approach to biogas" published on September 14th by the Swedish government has found that the economic and environmental benefits of using biogas can be notably expanded depending on its production method. The paper explores the benefits derived from the production of biogas through anaerobic digestion of waste as a means by which to double the amount of biogas produced whilst reducing environmental damage, primarily by cutting methane emissions.

Biogas is methane produced by the biological breakdown of organic matter in the absence of oxygen. Biogas originates from biogenic material and is a type of biofuel. Anaerobic digestion refers to a series of processes during which microorganisms break down biodegradable material in the absence of oxygen.

The study – commissioned by the Swedish Energy Agency and the Board of Agriculture and Environmental Protection Agency for the Swedish government – is the result of a government initiative to  increase the use of biogas in Sweden in the short and long term.

The production of biogas through anaerobic digestion of waste should, according to the paper, provide a valuable opportunity to stop the cycle of plant nutrients and thus provide a significant economic benefit in addition to the produced biogas.

The economic benefit derives from the fact that the value of biogas generated through anaerobic digestion could more than double from the current estimate of 1.5 terawatt hours to 3-4TWh.

The environmental and climate benefits, on the other hand, lies in that this method would cut methane emissions, use sewage sludge and manure, and use food waste from restaurants and industry.

The paper recomends a subsidy of 0.2 euro per kilowatt hour (KWh) is proposed for biogas produced from manure to help it become economically competitive.

“We want to increase the production of biogas that provides the greatest benefit; that is, from sewage sludge, food waste, restaurants and other food waste and manure. Biogas as fuel should be a priority for heavy vehicles in urban areas where the environmental impact is greatest,” said Eva Smith, deputy director general of the Environmental Protection Agency, during a statement.

Although this is good news for the biogas industry, much remains to be done to develop the potential of fuels such as biogas.

“A lot has already been done, but a lot remains to be done until biogas can become an integral part of the future of agriculture,” said Christel Gustafsson, head of the Swedish Board of Agriculture.

Bellona welcomes this report and is especially supportive of the fact that energy, agricultural and environmental government bodies cooperate to design this biogas strategy.

”Bellona has been working towards increasing cooperation and dialogue between the different sectors involved in biogas production in Norway. It is high time that the Norwegian authorities takes a similar intersectoral approach to find ways to increase biogas production for transport also in Norway,” says Tone Knudsen, biofuels expert from The Bellona Foundation.

”Moreover, biogas production leads to production of what is known as ”biorest-product”. Looking for good ways to use the biorest, such as for manure purposes or as soil improvement, should also be part of any biogas strategy”, Knudsen concludes.

Access the paper here (in Swedish only).