Where digitalization meets environmental efficiency

Metsä Group’s Äänekoski bioproduct mill is utilizing raw wood material and production side streams to manufacture a wide range of bioproducts. The mill represents the highest levels of energy, material, and environmental efficiency in the world. Siemens automation solutions and digital analyses of production data help streamline mill operations.

Today, companies that can fulfill sustainable production quickly and effectively have an edge in international competition. A case in point is the Metsä Group’s mill in Äänekoski, Finland. There, 1.3 million tons of pulp are produced annually as the raw material for paperboard, tissue papers, printing papers, and specialty products.

Abandoning fossil fuels

At the same time the mill also produces bioenergy and other bioproducts, such as product gas, sulfuric acid, tall oil, turpentine, and biopellets. How? “By fully tapping into production side streams and using 100 percent of raw wood material,” answers Ilkka Poikolainen, Vice President of Äänekoski bioproduct mill. And on top of that, the mill uses no fossil fuels. 

Although the new mill’s production capacity is nearly triple that of the previous mill in Äänekoski, it operates within the emission limits of the previous mill’s environmental and wastewater permit. It takes the best available technologies to produce results like these. One example is a highly efficient steam turbine from Siemens Energy, or Siemens Mobility hybrid locomotives for transporting pulp to Vuosaari Harbour. And of course, there are also the process automation and digital solutions from Siemens Industry.

The highest level of efficiency: From wood …

At the heart of the bioproduct site is the most efficient pulp mill in the world. Raw wood material is debarked, chipped, digested, washed, bleached, and dried during the pulp production process. The pulp is then sent to an automated distribution center and from there to customers. 

… to electricity

In the recovery line, the focus is on an advanced closed cycle in which water and chemicals are recycled and returned to the process for reuse. Odorous gases, for example, are converted into sulfuric acid, which is used to manufacture tall oil – an essential ingredient among others in glue, paint, and ink. The bioproduct mill also produces electricity from black liquor, which consists of wood and cooking chemicals. In fact, the bioproduct mill produces 2.4 times as much electricity as it needs, with the excess electricity being fed into the grid. 

“One of the central ideas behind the bioproduct mill is to expand the product range to entirely new bioproducts,” says Poikolainen. “The share of bioproducts manufactured from side streams represents 20 percent of the mill’s net sales, and that share is continuing to grow gradually.”

One of the central ideas behind the bioproduct mill is to expand the product range to entirely new bioproducts.
Ilkka Poikolainen, Vice President of Äänekoski bioproduct mill

Dependable thanks to cloud technology

Aside from delivering automation to different parts of the fiber line and the recovery lines, Siemens provides a centralized 24/7 automation monitoring service for Metsä Group's Äänekoski bioproduct mill. Via remote connections, information is gathered from more than 600 automation devices installed in multiple automation networks. Applications in MindSphere, the leading industrial IoT as a service solution from Siemens, perform diagnostics based on analyses of the data. This proactive digital service ensures uninterrupted production and can be expanded to include other Metsä Group mills.

Environmental efficiency: More to come

Metsä Group is currently carrying out a pre-engineering project to build a new bioproduct mill at its site in Kemi, Finland. If implemented in full, the total value of the investment would amount to €1.5 billion and an annual production capacity of approximately 1.5 million tons of softwood and hardwood pulp.


In addition to pulp, the mill would produce various other bioproducts. The main planning premises of the new bioproduct mill include completely fossil-fuel-free operations and 250 percent electrical self-sufficiency. 

With a production output of 1.3 million tons of pulp per year, Metsä Group’s bioproduct mill in Äänekoski, Finland, is the largest wood-processing plant in the northern hemisphere. The mill reached full production capacity in August 2018. Most of the softwood and birch pulp is exported, mainly to Europe and Asia. The new Äänekoski mill is called a bioproduct mill because it generates excess bioenergy, expands the product portfolio with new bioproducts, and uses no fossil fuels.

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