Since the global increase in energy use is showing few signs of slowing down, sustainable energy solutions have to be developed. For this reason, the energy of biomass has to be used more widely and more efficiently. In forests all over the world a huge amount of logging residue is left lying idle and the bioenergy unused. This could be changed by using Obey, a procedure for optimising bioenergy yield, based on long, Nordic traditions.

Obey is an acronym for "Optimising the bioenergy yield", referring to biomass used for producing energy. Walki, the leading producer of technical laminates and protective packaging materials, has a long experience of close co-operation with the forest industry and is familiar with the advantages that the procedure behind Obey brings. In order to promote the efficient use of wooden biomass globally, Walki is now launching the website www.obeyinfo.com.

"Obey is about using the full energy potential of logging residue and the trees cut down when thinning out forests. The first step is to let the residue and trees dry in the forest before they are chipped and transported. It's a law of nature that the energy yield increases significantly if you completely dry the material before burning it, compared with burning damp wood," says Walki's Arno Wolff, Vice President Sales and Marketing, Technical Products.

A complete procedure for sustainable energy yield
Obey embraces the entire procedure of harvesting, handling and using wooden biomass in a sustainable way. An important fuel for energy production is logging residue: the parts of trees that are left behind after the trunks have been taken by the paper industry or to sawmills.

The other source consists of thin trees that have been cut down to provide room for more profitable trees to grow. According to Obey, these trees and parts of the trees are left to dry at the logging site for three or four weeks before they are collected.

This allows free and environmentally friendly solar energy to dry the wood effectively, and leaves and needles not needed for energy production drop off, providing nutrients for the forest. Subsequently, the wood is stacked where the sun and wind can dry it further.

"If the stacked wood is protected from rain and snow with a suitable cover it will stay dry and not lose the attained energy value. Moreover, the wood will be easy to handle since it remains ice-free. Walki's covering material Walki-Biomass Cover has been developed exactly for this purpose. Since it is made mainly of fibre-based paper it can be chipped and burned together with the logging residue," Arno Wolff says.

Another step in the Obey procedure is to chip the wood close to the stacking site in order to minimise transport volumes and thus reduce the energy needed for transportation. If the biomass is dry, transport efficiency is boosted further since trucks can be filled without exceeding weight limits (no water is transported). Furthermore, by storing only dry biomass, decay is avoided.

"To retain biofuel's competitive edge, it should be utilised as close to the harvesting site as possible. This is also favourable in terms of local employment," Arno Wolff says.

Biomass from the forest is the future
If Obey is implemented step-by-step, the amount of energy obtained from biofuel can be significantly increased. The most important consequence of this is that large amounts of fossil energy can be replaced with renewable energy.

"Biomass is the most significant of the renewable energy sources in use, and forest bioenergy is by far the largest source, with the best potential to grow. Compared to many other bioenergy sources it provides for good net energy output, in other words, processing doesn't cause energy loss. Furthermore, the conflict of whether biomass should be used as fuel or as food can be avoided when using wood," Arno Wolff says.