Assessing Alternatives for District Heating

In order to accommodate the growing demand for hot water and the possibility of using an alternative district heating source, Portland State University (PSU) was trying to identify and evaluate future fuel sources for its campus through an objective process. This paper is focused toward developing an evaluation model to identify the most feasible fuel option for PSU’s district heating purposes. The study evaluates three fuel alternatives using the Hierarchical Decision Model (HDM) together with the Technology Valuation (TV) Model. The three fuels evaluated are natural gas, marine diesel oil, and pyrolysis oil. It is determined from the model using expert responses that natural gas is the preferred alternative. The highest weighting for the criteria was associated with cost while the lowest weighting was associated with environment. This chapter demonstrates an assessment approach of fuel alternatives of commercial heating system. HDM and TV Model are used to evaluate three fuels for heating system of PSU’s campus. The campus consists of approximately 60 buildings on 50 acres of land. The main heating system that PSU currently relies on consists of two heating plants with seven natural gas fired boilers. In addition, a 2.5 MW diesel fired turbine was installed in the university’s newest building in 2006. The campus also has seven small natural gas fired boilers that serve individual buildings in the area for PSU residents. On average, PSU’s heating system is required 8 months of the year for approximately 14 h a day, 6 days a week. The evaluation model utilizes different factors and expert’s subject judgments.