Together, Gasum and Stora Enso are leading the way in the circular economy

Much lower carbon dioxide emissions and good fuel economy are just two reasons why liquefied biogas has become an increasingly popular heavy-duty transport fuel. Gasum and Stora Enso have now innovated a smart way to produce liquefied biogas using the wastewater effluent from Stora Enso’s pulp and paper mill in Nymölla, Sweden. The investment is the first of its kind and has already inspired others to take a step into the circular economy.

Gasum and Stora Enso are two companies that have come far in their approach to the circular economy. Their groundbreaking work has resulted in the companies developing a sustainable solution to process the residuals in the wastewater at the paper mill. The new biogas plant in Nymölla has just started up and will deliver the first liquefied biogas in May.

Renewable fuel for the future is produced next door

Gasum is making a circular statement with the biogas plant at Stora Enso’s pulp and paper mill in Nymölla. It recovers organic matter from the wastewater during the treatment process and turns it into liquefied biogas. More pulp and paper mills should follow the example set by Stora Enso. The liquefied biogas produced can be used as a heavy-duty transport fuel, for example. Gasum’s network of liquefied gas filling stations is expanding the whole time, also in and around Swedish factory towns. Gasum’s filling station in Kristianstad is just some 20 km from the Nymölla plant.

“Demand for liquefied biogas is showing rapid growth from one year to the next. This, together with the fact that many companies want to be part of the circular economy, means that we will soon see more local and regional investments. The Nymölla project has opened the door to the future,” says Erik Woode, Director, Project Development ＆ Management, Gasum.

Working together for a sustainable future

Gasum’s biogas plant in Nymölla makes Stora Enso’s pulp and paper mill a co-producer of renewable energy and enables it to take a further steadfast step into the circular economy. The Nymölla plant is expected to produce around 75–80 GWh of biogas a year, which is equivalent to the annual consumption by as many as 200 trucks. But there is also demand for liquefied biogas in shipping and industry.

“If more people dare adopt a new approach and use existing resources in the right way, we can reach common emission targets and combat climate changes,” adds Erik Woode.

How wastewater becomes liquefied biogas

Stora Enso’s pulp and paper mill in Nymölla produces around 340,000 tonnes of pulp and 485,000 tonnes of wood-free office paper each year. Gasum’s biogas plant is wall-to-wall on the mill site. Large pipes conduct the wastewater from the paper mill to a large buffer tank, where it is optimized using nutrients. The water is then pumped into a reactor where bacteria break down the organic substances in the water to create biogas. The biogas is separated from the now-clean water. Whereas the water is returned to the paper mill, the biogas goes for further cleaning and upgrading before being cooled to around -160°C to liquefy it. The liquefied gas is then stored in an insulated tank before being collected by Gasum’s tanker trucks.