Evaluation of Geothermal Energy as Heat Source of District Heating Systems in Tianjin, China

Abstract

The major energy structure for Tianjin, China includes the conventional energy sources such as coal, petroleum and natural gas. There is abundant medium/low temperature geothermal energy reserve in Tianjin. Since 1960s, geothermal energy has been explored and utilized, and step by step, it has also become an important supplemental energy resource, thanks to the outstanding results achieved in its comprehensive utilization. How is the performance of geothermal energy as a district heating energy source compared with those conventional sources? Using a newly developed community district heating system as case study, this paper describes the evolution of the geothermal heating system with fossil fuelfired boiler house for peak load shaving in Tianjin. It analyzes the energy saving of that heating system. Finally, this paper quantitatively compares the performance of low/medium geothermal water heating system with the systems using those conventional energy sources. The comparison is in three major areas: economic impact, energy utilization efficiency and environmental impact. The Net Present Cost (NPC) model is used to evaluate the overall cost impact considering both capital cost and annual operating and maintenance cost. In addition, this paper explores the environmental impact of using the conventional and geothermal energy sources.