The role of a paper mill in a merged district heating system

Recent studies have shown that there is great potential benefit in utilities collaborating around heat supply. Analyses based on an extended system boundary clarify the advantage of mutual co-operation in the district heating markets. The purpose of this study is to show how far a local paper mill affects the degree of co-operation between two utilities. Current and future electricity prices and existing and potential plants are considered in the different scenarios in the study. The results in all the scenarios clearly show that the paper mill plays an active role in an integrated heat supply system. The scenario where co-operation, new plants and future electricity prices are considered, gives the lowest total system cost. A new back pressure turbine with a higher electricity-to-heat output ratio in combination with high trade prices promotes increased electricity and heat generation in the co-generation plant. The proportion of combined heat and power in district heating would increase if co-operation between the players were encouraged. (C) 2003 Elsevier Science Ltd. All rights reserved.