Self-sufficient thanks to a biomass-powered cogeneration plant

“The new biomass-powered cogeneration plant has an output of 5 MWel and 15 MWth and has been in continuous operation at full capacity for more than a year without any problems. We wanted to be self-sufficient in terms of energy at our production site, and we succeeded at that,” Gerhard Pirih, plant manager of Hasslacher Eco Power at Hasslacher Group’s site in Preding, says. In recent years, the group has made substantial investments in the modernization of the site. Furthermore, the capacities of the sawmill, further processing plant and pelleting mill were increased significantly. A continuous kiln was put into operation together with the CHP plant, which brought the annual drying capacity to 280,000 m³. In total, around 30 batch kilns are in use at the Preding site. The capacity of the pellet mill is 110,000 t a year. Two belt dryers (7 and 4 MW) are used to dry the sawdust for pelleting.

Construction in record time

“We were faced with the question of whether to replace the old plant, a 10-MW hot water boiler that had reached its limits, or to invest in a biomass-powered cogeneration plant. Our goal was to create an integrated, energy self-sufficient production site. Therefore, the decision was an easy one: We would build a CHP plant,” Peter Fercher, consulting engineer for the Hasslacher Group, explains. Hasslacher and Urbas have been working together for a long time and trust each other. “We are fully convinced of Urbas’s technology,” Fercher emphasizes. The old boiler still serves as a stand-by and to cover peak loads.

The €20 million project had been planned before the outbreak of the coronavirus pandemic. However, when the Green Electricity Act came into effect, it delayed everything. Finally, in September 2020, the order was placed and in February of the following year, concrete construction work started on a 1-ha big area on the edge of Hasslacher’s premises. All key components of the eight-story building with its height of 32 meters have been supplied by Urbas. The order includes the turnkey construction of the CHP plant complex on top of the previously completed concrete work. “Despite all the difficulties we had during the pandemic, we were able to build the entire plant and put it into operation in a record time of just nine months. This was only possible thanks to the excellent collaboration with all the companies and their employees, especially Urbas’s project manager, Michael Skreinig,” Fercher tells us.

“We have been generating heat without interruption since the beginning of December 2021, and the turbines have been in continuous operation since early February – and both have been operating at full capacity,” Pirih explains. “The heat we generate is sufficient to satisfy the annual demand of the site,” he adds. The new plant generates 40 GWh of electricity each year, which corresponds to the annual consumption of around 12,000 households.

Flexible use of fuel

Hasslacher Eco Power uses around 250,000 stere of bark and wood chips a year as fuel. The bark comes from the log wood which is cut at the site, while regional forest owners and landscaping companies provide the energy wood which is processed into wood chips. Around 140,000 stere of bark are needed each year. The Urbas plant can process unchopped 30 to 100 cm-big pieces of bark. Especially when it comes to wet and moist bark and sawdust with a water content of up to 60%, the robust Urbas machines always deliver full performance, as the Carinthian specialist for biomass plants emphasizes.

Once a month, a forestry company stops by with a chipper and chops up the energy wood. Hasslacher Eco Power does not buy the biomass and industrial wood itself. This is done by the group’s central purchasing department. Damaged or beetle-damaged wood which is not suitable for sawing is used for combustion. Usually, the fuel is stored at the Preding site for three to four months. In two containers, the bark and wood chips are mixed in a ratio of 2:1. Every 1.3 minutes, fuel is transported to a height of 6 meters with the help of a robust trough chain conveyor and fed to the combustion chamber by a hydraulic pushing device.

Monitoring is important

“Water quality is of central importance for the power plant. The water here in Styria is very rich in minerals, which is why it has to be completely demineralized in a treatment plant. There are very precise specifications and guide values for the quality of the boiler water that is used. The quality of the condensate, the feed and boiler water as well as live steam is continuously monitored using online measurement. This ensures the longevity of the plant components – especially that of the steam boiler and the steam turbine. Basically, the entire boiler plant system controls itself. We have a total of four monitors for plant control and monitoring. If necessary, Urbas can also provide support via remote maintenance,” Pirih explains. “After 72 hours without any intervention or check, the plant would turn off automatically. In German, this is called BosB, which means operation without constant supervision,” Fercher adds.