What is biogas made from?

Most of the side-streams originating in society currently go to waste. If these could be recovered, it might be possible to manage the emissions they release and recover their nutrients for further use. Biogas produced from these side-streams can be used to replace fossil fuels in road and maritime transport, and in industry for example.

Biowaste

• Biowaste is produced by stores, enterprises, industry as well as by private consumers.

• When biowaste is processed into biogas rather than compost, energy can be recovered to replace fossil fuels and recycled nutrients to replace commercial fertilizers.

• Almost half of Finland’s biowaste is currently still not recycled. The Waste Act is currently being amended and also the EU will require separate biowaste collection at all properties in 2025. Technology is being developed to separate organic waste from general waste. Oulu is one of the places in Finland where such development is taking place.

Side-streams from agriculture and forestry

• Recovery and use of straw, fallow grass and wood material unsuitable for processing that originate in agriculture and forestry has no adverse effects on production.

• Also cultivated plants can be used.

  • g. root vegetables, corn, sugar beet, onion…

• Manure

  • Around 15 million tonnes of manure are produced in Finland each year.

  • Processing manure into biogas enables climate emissions to be reduced and nutrients to be recovered.

  • Biogas plants need a special infrastructure to be able to process manure.

Industrial side-streams

• Industrial side-streams can include material left over from production processes that is not really waste.

  • g. grain husks, mash, surplus slaughterhouse products, sceptic tank and grease trap sludges

  • Also spoilt produce such as yoghurt or confectionery

Sewage sludge

• Sewage sludge collected in wastewater treatment plants is rich in organic material suitable for biogas production.

• Sludge contains significant amounts of phosphorus, which is a dwindling natural resource and so important to recover.

Gasum is the largest biogas producer in Finland and each year recycles around 500,000 tonnes of biomass, turning it into a low-emission transport fuel, biogas. Besides biogas, Gasum’s plants produce various recycled nutrients.

Sources: Finnish Environmental Institute, Gasum

Updated 16.10.2021