In the summer of 2025, Progroup began taking over energy generation for the paper machine (PM3) at the Progroup site in Sandersdorf-Brehna. It was the successful conclusion of a planning, construction and testing phase that lasted more than four years and was overseen by a highly motivated team led by project manager Jan-Simon Liedtke and his production manager Thomas Jänisch. “With this power plant, which is operated using substitute fuels, we can cover all of the demand for steam of PM3 and so replace 95 per cent of the fossil fuel (natural gas) with sustainable substitute fuels. This takes us a big step closer to achieving our goal of being as independent as possible from fossil fuels,” says Liedtke with delight.

Perfect planning ensures a trouble-free start

In May 2025, the team led by Liedtke was able to start the hot commissioning. This is a test operation in which the system is repeatedly switched off and readjusted. “We then moved on to trial operation. The power plant can only be put into operation once it has run smoothly for 28 days in a row,” explains Liedtke.

According to Thomas Jänisch, the thermal output of the power plant is 115 megawatts, of which 7.5 megawatts are generated from biogas that is produced in the paper machine’s circulating water treatment plant. The rest is produced using substitute fuels. The external gas connection is only needed to start the power plant or if the fuel mix does not meet the required specifications. “Here in Sandersdorf, we have the biggest waste-to-energy plant of its type in Europe. It’s configured precisely to suit our paper machine and covers 100 per cent of the demand from PM3,” says Jänisch with real pride.

But that’s not all. The new power plant will be more sustainable because of its closed circular economy at one site. Residual materials from the paper factory have a high biogenic content, which means they provide sustainable heat and around 60 gigawatt hours of green electricity per year. The crucial factor is the design of the site. The sewage sludge from the circulating water treatment facility is fed from the paper machine to the power plant via a short pipe bridge. And the waste materials from the paper factory, known as rejects, also remain at the site and no longer have to be disposed of externally. In addition, Progroup relies on a sustainable mix of fuels. 50 per cent of the fuels come from biogenic materials.

Production flow

Innovations improve efficiency and sustainability

One important basis for kitting out the new plant was the wide range of experiences gained with the first waste-to-energy plant in Eisenhüttenstadt. Together with the new technological possibilities, they led to important innovations. In the stationary fluidised bed, the quartz sand lies on the bottom and is heated up to a temperature of 850 degrees once using gas. Once the temperature has been reached, the substitute fuel is blown into the boiler. It is heated up by the quartz sand and then in turn heats the newly injected substitute fuel again. This means that 99.9% of the substitute fuel is thermally utilised in the shortest possible time, with the remaining tiny amount being bound with the sand as ash. “It works like a perpetual motion machine, once the operating temperature has been reached, we no longer need any gas support,” explains Liedtke.

The high availability of the machine represents another step forward. The new power plant can be started up or shut down in just 13 hours. The key reason for this is the water-cooled combustion chamber, which cools down faster than combustion chambers built from bricks. In addition, the brickwork does not have to be removed before each inspection and then rebuilt afterwards. “In conventional plants, the inspection takes around six weeks, but with us it generally only takes four. This saving of two weeks a year is huge,” says Jänisch enthusiastically.

Equally crucial factors for the sustainable operation of the power plant in Sandersdorf are the closed water-steam cycle, which allows the treated boiler installation water to remain in the system even when the paper machine stops production, along with the flue gas cleaning. Here too, Progroup is working with the most powerful system of its kind available on the market. According to Liedtke, this very much reflects the corporate philosophy that Jürgen Heindl formulated right from day one: “Investment and innovation are siblings that are inextricably linked together.”