Logging residue is an inexpensive and easily accessible source of biofuel but to improve the energy content it must first dry on the ground. After that it can be stored in piles for several months. To shelter the piles from moisture due to rain, snow and ice, Finnish-based Walki has developed a paper-based, waterproof cover that can be chipped and burned together with the residue.
At first glance, Walki’s biomass cover doesn’t look very high-tech, but the company says it’s an ingenious invention that very efficiently improves the energy content in logging residue. The cover itself is a four-metre wide laminate, mainly produced from renewable fibrous materials. It shelters the top of the pile but leaves the sides open, allowing moisture to evaporate.
A very thin plastic layer within the cover makes it both waterproof and very strong, but thanks to the characteristics of the plastic, the cover can be chipped along with the residue and used as fuel as well.
“This biomass cover is already the widest of its kind on the market. Now we are also developing a six-metre wide version that can cover even bigger piles of logging residue and other wood-based biofuels,” says Hannu Nieminen, Product Line Manager at Walki.
In addition to shielding the residue from water and snow, the Walki biomass cover also protects the residue from freezing, which can transform the pile into an icy heap that’s almost impossible to handle and has low energy content.
“The phenomenon is familiar to anyone who has piled chopped firewood outside and forgotten to cover it,” says Nieminen. “In the winter time, the wood is icy and heavy and produces much less heat than dry firewood.”
Walki says Finland and Sweden are pioneers in harvesting energy wood, but because energy saving and biofuels are the latest buzz, interest in their technology is increasing in other parts of the world as well.
“Energy wood is, in many countries, an almost unused resource for producing energy in an environmentally sound way,” says Nieminen. “Our product maximizes the energy value of logging residue; measurements have shown that the solids content of wood can be raised by as much as 15 percent by using the cover.”
In Finland, the main reseller of Walki’s biomass cover is Uittokalusto Oy, a Finnish company owned by Grube KG Forstgerätestelle of Germany. The company has been selling the cover for about five years now and is very pleased with the feedback from customers. The main customers are big forest companies in Finland and their subcontractors.
“The cover is easy to spread with the same machinery that gathers the residue in the woods,” says Ilkka Leskinen, Sales Manager at Uittokalusto. “Our customers are satisfied with the benefits of the biomass cover and how easy it is to use the product.”
Walki Group is a leading producer of technical laminates and protective packaging materials, specializing in the production of fibre-based, intelligent, multi-laminate products for markets as diverse as energy-saving construction facings to barrier packaging applications. Walki Group has operations in Finland, Sweden, Germany, Poland, the UK and China.
