Potentiale zur energetischen Nutzung von Biomasse in der ... - EPFL

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trees of large diameter that could not be extracted from forest stands by less costly drugging by soil
procedure. According to this technique the trees are felled by chain saw and moved out from forest
stand by cable crane to the maximum allowable distance of 600 m. The assortment of timber qualified
as energy wood is further transported by truck to the end-use facility where it is chopped by a large-size
chipper. The costs incurred through the use of this technique are given in Table 50. Here again the costs
of felling/extraction of trees are not included, since they were allocated to other timber assortments
(construction and industry wood).
Estimation of the presented cost range for supply of the chopped wood using different technology
options was made by WSL based on interviews with relevant forest enterprises mainly in the Germanspeaking
part of Switzerland. It is expected that these costs could be decreased as an effect of
rationalisation achievable through higher degree of work mechanisation, advancement in harvesting
machinery technology and lowering of overall transaction costs due to centralised purchase and bigger
consumption volume. For the first prototype GIS model estimate it was decided to use the average
values given in the respective column of Table 50. These data could be further adjusted based on
practical information from the forestry entrepreneurs in specific regions of Switzerland.
Since the presented costs of biomass harvesting are given in relation to the volume of chopped wood
(Sm 3 ), therefore an appropriate conversion factor should be applied. According to the data of
Holzenergie Schweiz (2003) this factor is equal to 2.8 Sm 3 per one cubic meter either of resinous wood
(spruce/fir) or deciduous species (beech).
Another important indicator to be taken into account while estimating the biomass farm-gate prices per
energy unit is the energy content of different types of biomass. The value of this indicator is highly
dependent on the humidity of wood, which in turn depends on the time of harvesting, and it also
significantly varies across different species. In the WSL 2003 study the following values (Table 51) are
proposed to measure the energy content of different types of biomass (coniferous trees, deciduous
trees, wood residues) at different physical states (fresh wood, wood dried in summer, technically dried
wood).
Type of biomass
Moisture content (atro)
100% (fresh wood) 50% (summer dried) 25% (technically dried)
Resinous wood 500 600 650
Deciduous wood 850 950 1000
Wood residues 425 525 575
Table 51 Energy content of main types of biomass (kWh/Sm 3 ). Source: WSL 2003.
The calculation results of the biomass farm-gate prices could be presented in the form of a thematic
map showing the amounts of available energy biomass resources (in Sm 3
) and its respective farm-gate
prices (per Sm 3 or per kWh) across different forestry sites within a given region.
10.2.3 Marginal price of delivered biomass
In the operation cost of generic woody biomass energy installation the cost of biomass transportation
may represent a significant portion of the overall cost of the biomass feedstock. Considering the
possible disparities in the biomass farm-gate prices across different forest exploitations and varying
remoteness of the biomass sources from projected energy facility’s site, the price of delivered biomass
feedstock could vary significantly depending on the specified location of the energy installation. In such
a way, the cost of delivered biomass feedstock may become a decisive factor while making decisions
about the deployment of a biomass fuelled energy facility and choosing its optimal location.
To tackle this issue it is proposed to employ a special GIS model methodology that would make possible
the assessment of cost of the delivered biomass feedstock based on the marginal price method (Noon et
al., 2002). Such a methodology allows for choosing appropriate forest exploitations that would supply
biomass feedstock to the projected energy installations of known capacity and at the given locations