Oulu taps into the best sides of circular economy and bioeconomy – biogas utilised by both companies and the city

The Oulu biogas plant, a facility using separately collected biowaste, side streams of the food industry and sewage sludge, produces biogas for traffic and recycled fertilisers for agriculture. The unbroken chain of circular economy has generated significant expansion plans in the area.

60,000 tonnes of biodegrading waste and sludge is quite a heap of materials. It also contains a large amount of clean energy. That is the energy bomb processed by Gasum’s biogas plant in Oulu each year, resulting in 35 gigawatt hours (GWh) of biogas.

Kempeleen Jätekuljetus collects and transports biowaste to the biogas plant in Oulu. Biowaste is collected from both private households as well as shops and companies.

“Our vehicles are operating at maximum capacity and more and more households are constantly added to our biowaste collection services. Trade produces the largest amounts of waste by weight,” says Mikko Räsänen from Kempeleen Jätekuljetus.

Local entrepreneurs actively involved

The production process of biogas creates digastate, an excellent recycled liquid fertiliser. The digastate increases the soil’s pH value, reducing the need for liming and improving the structure of the soil.

“These are some of the best parts of circular economy. Recycled fertiliser is an affordable, cost-efficient way of maintaining the nutrient levels of cultivated plants and the soil,” says agricultural entrepreneur Mikko Viitala who has several years of experience.

Viitala has used the fertiliser produced by Gasum’s biogas plant since the beginning. He also works on the field plots of other farmers in the Muhos area with his 17-cubic metre and 15-metre covering spreader, spreading about 40,000 cubic metres of sludge per year. The logistics with Gasum work effortlessly.

Viitala has about 8,000 cubic metres of storage space, about half of which is reserved solely for recycled fertiliser. The fertiliser is spread in the spring before sowing, in the spring when the fields are replenished or in the autumn after threshing.

Recycled fertiliser contains sufficient levels of phosphorus and a good quantity of nitrogen which must be slightly added to when sowing to ensure a good start for the crops. The fertilisation is always based on soil-fertility testing. Viitala is extremely satisfied with the fertiliser.

“Heat-treated and sanitised recycled fertiliser contains low levels of heavy metals and is suited to all cultivated plants, with the exception of breadcorn. Each year, I apply it on about 200 hectares of my own fields, depending on the crop rotation,” says Viitala.

Corporate social responsibility as part of companies’ journey

In Oulu, biogas is transformed into fuel for gas vehicles, distributed at two Gasum gas filling stations. For the time being, the filling stations in Oulu are the northernmost stations in the gas filling network, supporting the gas-fuelled arterial traffic from southern to northern Finland. In the Oulu region, many taxis and some local buses run on gas.

Established in 1937, Vähälä Yhtiöt is a full-service logistics group that operates globally as a partner of DB Schenker. Corporate social responsibility has always been an integral part of the company, translating to comprehensively caring about the employees, customer needs and a clean future.

Covering 240 vehicles, corporate social responsibility at Vähälä means green investments made at an accelerating pace. Practical action includes reducing emissions, promoting energy efficiency and using alternative fuels.

“The customers are increasingly interested in our methods of transporting their goods. Our philosophy is that the world and technology are evolving and so should we,” says Ari Karjalainen, Head of Supplies at Vähälä Yhtiöt.

The Oulu-based company deployed its first tractor unit using liquefied natural gas in 2019. The drivers have praised the vehicle for being silent and easy to drive and refuel.

Finnish Government supports the transition of heavy traffic to low-emission alternatives through a procurement subsidy. Vähälä Yhtiöt plans to use the subsidy to procure five new gas-operated vehicles, three of which will be used for distribution. They will operate on compressed natural gas (CNG) that may also be biogas (CBG).

Local entrepreneurs actively involved

The production process of biogas creates digastate, an excellent recycled liquid fertiliser. The digastate increases the soil’s pH value, reducing the need for liming and improving the structure of the soil.

“These are some of the best parts of circular economy. Recycled fertiliser is an affordable, cost-efficient way of maintaining the nutrient levels of cultivated plants and the soil,” says agricultural entrepreneur Mikko Viitala who has several years of experience.

Viitala has used the fertiliser produced by Gasum’s biogas plant since the beginning. He also works on the field plots of other farmers in the Muhos area with his 17-cubic metre and 15-metre covering spreader, spreading about 40,000 cubic metres of sludge per year. The logistics with Gasum work effortlessly.

Viitala has about 8,000 cubic metres of storage space, about half of which is reserved solely for recycled fertiliser. The fertiliser is spread in the spring before sowing, in the spring when the fields are replenished or in the autumn after threshing.

Recycled fertiliser contains sufficient levels of phosphorus and a good quantity of nitrogen which must be slightly added to when sowing to ensure a good start for the crops. The fertilisation is always based on soil-fertility testing. Viitala is extremely satisfied with the fertiliser.

“Heat-treated and sanitised recycled fertiliser contains low levels of heavy metals and is suited to all cultivated plants, with the exception of breadcorn. Each year, I apply it on about 200 hectares of my own fields, depending on the crop rotation,” says Viitala.

Aiming for the production of liquefied biogas

Gasum and Oulun Energia are planning the construction of a joint biogas plant in connection with the Laanila eco power plant. The plant will use biodegrading waste found in mixed waste and produce about 40 GWh of liquefied biogas (LBG).

At the same time, Gasum is planning to expand the existing Oulu biogas plant to increase its biogas production by 20 GWh per year. According to the plans, the amount will be forwarded to Laanila for liquefaction.

Text: Vesa Vainio

15.11.2021