Clarification, 24 September 2026: The distinction between using carbon dioxide as a raw material and creating a permanent carbon sink has been clarified. The original publication date has been retained.
Auris acquired a majority stake in the Mäntsälän Biovoima plant in autumn 2023
and set out to develop it systematically into
Finland’s most versatile factory producing energy gas
by recycling biomass.
Our factory is the only biogas production unit connected
to Auris’s gas distribution network. This enables the facility
to serve in various ways as an injection point for biogas into the network.
Growing production of environmentally friendly biogas improves Finland’s security of supply and offers a straightforward way to reduce emissions from energy use.
A versatile production facility
Our Mäntsälä biogas factory currently uses a wide variety
of feedstocks, including biowaste and side streams from the food industry
and retail, household biowaste and other biological raw materials
suited to our process. The share of the last two categories is growing
continuously. In the coming years, biogas will also be produced from
sludge from wastewater treatment plants.
Because of our industrial-scale, versatile production, we describe
the facility as a biogas factory rather than a biogas plant. In addition to production,
the factory will soon start using a compressor to inject gas
from the distribution network into the transmission network.
This unique transfer of gas from our low-pressure
4-bar production system into the high-pressure 50-bar network will begin
in early 2025. Thanks to the Mäntsälä factory, biogas will replace natural gas
to the extent that, locally, biomethane will account for a larger share
than natural gas.
The factory has a quality analyser to ensure that the gas
meets the national network’s quality criteria. The analyser can
also be used to monitor gas quality from other biogas plants
when gas is brought to Mäntsälä from other facilities
for the biogas container injection service.
Carbon dioxide capture has enormous potential
We are also developing biogenic carbon dioxide capture.
Biogenic carbon dioxide is carbon dioxide that has been bound
in biomass and is released into the atmosphere during biogas production
unless it is captured. Raw biogas consists of 50–70%
biomethane, with the remainder being carbon dioxide.
We are currently looking for users for the carbon dioxide. It can be
used as a raw material in products such as concrete, synthetic
fuels and synthetic food. Using carbon dioxide as a raw material does not in itself make the plant a permanent carbon sink.
The climate impact and carbon storage duration depend on
the application and the entire production chain.
Carbon dioxide utilisation is extremely important for the entire
biogas sector. As annual biogas production rises to four terawatt-hours
by 2030, it will yield hundreds of thousands of tonnes
of carbon dioxide each year.
We are investing heavily in carbon dioxide capture. It is not only
environmentally friendly but also cost-effective. The carbon dioxide
capture facility accounts for as little as less than one fifth
of our factory’s costs.
The compressor station, quality control and future carbon dioxide
capture will all be integrated into our biogas factory’s control room.
In the future, control and monitoring of our partners’ production units
and our own future factories can also be connected
to the Mäntsälä control room where this makes sense
for the biogas plant concerned.
Room for growth anticipated well in advance
The factory is relatively new: construction began in 2017,
and it was commissioned in 2020. When the plant was designed,
the growing need to collect biowaste and process it
into biogas was already apparent.
Mäntsälä was chosen as the location because of its excellent
logistics connections. Biowaste was selected as the feedstock because
its volume was expected to grow faster than that of any other raw material
suitable for biogas production.
The forecasts for growth in biogas production made during the factory’s
design phase are now being realised as we build a new
production line. It will more than double the factory’s annual
biogas output from the current 16 gigawatt-hours
to 35 gigawatt-hours. At the same time, annual biomass
processing capacity will increase from 20,000 tonnes to 45,000 tonnes.
The expansion will be completed by the end of 2025.
Demanding processing
Processing biowaste at the factory requires expertise, because
the biological material contains much more than biowaste alone. The waste
goes through pretreatment equipment that separates packaging materials
from biological material. This is the factory’s
most technically demanding process. Other material separated from the biomass
is sent as reject material to Ekokem or Vantaan
Energia’s waste-to-energy plant for incineration.
Jani Hautaluoma, Biogas Business Manager, Auris Energy, jani.hautaluoma@aurisenergia.fi