First the moist wood shavings, which accumulate thoughout the production processes at the sawmill, have to be dried. The energy needed for the drying is most often provided by the burning of bark, which likewise accumulates at the sawmill. In many cases the bark is used in power-heat coupling facilities that generate electricity and waste heat. The latter can be used to dry the wood shavings for further processing.
After the shavings are dried and reduced to small pieces they are extruded through the holes of a so-called matrix with high pressure – quite like minced meat. The resulting product are wood pellets.
To facilitate the pressing process, small quantities (max. 1.8 %) of corn starch are added. The pellets, which are heated up during the pressing process, are then cooled, sieved and stored for delivery to customers or wrapped up to be sold in bags.