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Fig. 2.
Different interactions between companies and biomass flows
The different processors have sector specific ways of buying in supply. Dedicated
biomass power plants secure their supply chain with long-term contracts of several
years (as long as possible without freezing the market price). The same is true for bio-
fuel producers. The situation is slightly more relaxed for anaerobic digesters since their
capital costs are lower. However, they process considerable quantities of organic waste
that are usually governed by long-term contracts (of up to 20 years). Composters and
co-firing plants can take in biodegradable waste quite spontaneously (and potentially
sporadically in the case of co-firing). They don't require upfront investment but simply
have to calculate their fees against operational costs. As this already indicates, the du-
ration of contracts with suppliers very much depends on the size of the processor and
the specifics of the biomass resource.
Furthermore, the revised agent-based model will distinguish between mate-
rial/energy and information flows. The use of biomass is path-dependent (cascading)
or may entail trails for recycling organic waste whereas the diffusion of information
is not. Following [6] we can discriminate between walks, trails, and paths. Walks are
sequences of flows where nodes as well as ties are passed time and again e.g. money
handed on in payments. Trails are sequences where nodes, but not ties, are passed re-
peatedly. Paths are sequences in which neither nodes nor ties are passed more than
once. The flows are transferred in their entirety. Material/energy flows generally belong
to this last category representing the irreversible dissipative economic structures of the
real world. Although recycling reintroduces trail characteristics these may be neglected
since we don't simulate regional energy supply or nutrient cycles.
With regard to information, [6] distinguishes between serial and parallel process-
ing. The diffusion of information (price, quality and quantity) of agents operating in
