OBEY is a procedure and a system of practices that will ensure the maximum efficiency and energy yield of the biomass which is used for producing energy. This standard of activity is necessary to ensure that consecutive stages of the production chain will serve each other in efficient harvesting and processing of the energy yield.
OBEY CONSISTS OF THE MEASURES OUTLINED BELOW:
Harvesting energy harvest
The wood needed to produce energy is obtained from two main sources: firstly, logging residue, i.e. the parts of trees that are left behind after the trunks to be used by the pulp and paper industry and sawmills have been felled and taken away, and secondly, from locations where the woodland has been thinned out to allow the more profitable trees more room to grow. In both cases, the wood needs to be harvested more precisely than normal. To achieve this, changes in working methods, work management processes and training are required.
Drying energy harvest
Both logging residue and thinned wood needs to remain at the logging site for three to four weeks before being collected, depending on the weather conditions. There are two reasons for this waiting period: firstly, free and environmentally friendly solar energy is needed to dry the wood, and the drying effect of the sun is much more effective on wood that has not yet been stacked. Secondly, the minerals providing nutrition for the growth of the forest are mainly stored in the needles and small branches which will drop off during the drying phase.
Stacking energy harvest
The wood has to be stacked in such a place that chipping and transport equipment can reach it. Whenever possible, the timber stacks should be located where the sun and prevailing winds will speed up the drying process. To achieve this, the compass points and terrain must be taken into account. This can further increase the dry biomass content of the energy wood as much as 5 per cent.
Protecting energy harvest
Stacked wood must be protected with a suitable cover to ensure that any rainfall will not wet the wood that has already been dried by the sun. Preventing snow and ice from getting into the timber stacks is also important because any snow or ice ingress will make chipping the wood more difficult and reduce the quality of the energy yield. The cover must be such that it can be chipped and burned with the wood. Furthermore, the cover must be manufactured from renewable raw materials – otherwise, the chips cannot be called 100-per-cent renewable. Video
Chipping energy harvest
The wood should be chipped as close to the stacking site as possible to minimise the volume of wood to be transported and thus reduce the amount of energy needed to transport the wood. The wood to be chipped must be as dry as possible as wet biomass rotting in a heap may loose as much as 2-3% of its energy yield per month. Quick rotting also increases the risk of accidental ignition. What's more, rotting releases so much methane that it decreases the positive environmental effects of bioenergy to a large extent.
Transporting energy harvest
The aim of drying, protecting and chipping the wood – in addition to improving the quality of the biomass – is to favourably affect transport. Dry wood is lighter and will thus be more affordable to transport. The heavy water in wet wood easily increases the load weight to a level which is higher than the approved limits. Furthermore, chipping the wood clearly reduces the transport volume. This means that less energy and less transport equipment will be needed. Lighter and more compact loads mean fewer loads, and this reduces the strain on the terrain and roads.
Utilising energy harvest
The forest bioenergy should be utilised as close to the harvesting site as possible to minimise transport distances and retain it's competitive edge. Local utilisation of wood is also favourable in terms of decentralising energy production and expanding its favourable economic and employment impacts.
Value of energy harvest
By implementing the above-mentioned measures, the amount of energy obtained from biomass can be increased by 5–15 per cent. This is a significant increase. It means that the cost of generating one kilowatt-hour with wood will be considerably reduced; this makes renewable energy a more competitive alternative and increases people's willingness to invest in its utilisation. Most importantly, however, it means that large amounts of fossil energy can be replaced with renewable energy; this can be achieved merely by improvements to energy-wood harvesting methods.
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