1988

Tamminen, Eero; Forsström, Juha

The linear programming model of forest products industries documented in this report is a mathematical representation of resource allocation alternatives in the production system. The model is developed for the investigation of feasible and optimal resource allocation structures under varying assumptions. These assumptions define availabilities of primary resources, process alternatives, technological development trends, marketing possibilities, requirements on final production, capacities, environmental factors and the objectives applied in optimisation. Raw wood and energy are the most important primary resources in forest industries, and in the production of paper these two primary resources substitute each other. For many paper grades, the same quantity can be produced by using energy and wood in varying proportions. The flow of resources in forest industries forms a very complicated network with many process alternatives and many ties between the processes. Combined production of process steam and electricity largely based on waste fuels from the production processes is essential for production economy. Owing to this complicated structure of the forest industries' resource allocation alternatives, a mathematical model is a necessary tool for a systematic analysis of the alternatives. The model documented here is a static, one-period model. It can be extended to a dynamic LP model or to a model which is regionally divided, and there are also other development possibilities. The model is developed as a part of a national energy model research project. The objective of the project is to develop independent models of the most important sectors of the energy economy, which can be integrated to form a national model. The approach for LP model construction applied here can be summarised as follows: Linear programming is a mathematical theory of resource allocation. To construct an LP model of forest industries amounts to a thorough study of the real resource allocation alternatives in the system. The results are documented in the form of the constraint matrix of the mathematical problem. Standard forms are developed for the definition of constraints, variables and parameters.