Cost Assessment of a District Heating System in Northern Japan Using a Geographic Information–Based Mixed Integer Linear Programming Model

Abstract

This paper presents a geographic information-based mixed integer linear programming model for a district heating system design. The model minimizes the annualized investment and operation costs of the system, with the key results showing the optimal distribution network structure and optimal capacity and dispatch of heat plants. A network topology of nodes and edges, providing accurate geographic representation of the district, is generated using a geographic information system and acts as a constraint. A case study is conducted for a district in Hirosaki city, located in the northernmost prefecture of mainland Japan. The results demonstrate the considerable economic benefits of integrating locally available woodchips in heat-only boilers instead of using city gas due to lower fuel costs. Low temperature operation reduces the fuel costs due to less network heat loss compared to medium temperature operation, but it is overcome by the cost of the larger pipe size and the pumping power. Implementation of the district heating system to the case area encourages sustainable development through economic favorability, decreased primary energy consumption, and considerable CO2 emissions reduction, compared to the current heat supply structure.