Study on Low Carbon Energy Supply to the District Heating and Cooling Plants and Buildings with a Waste Heat Pipeline in Yokohama City

Abstract

District heating and cooling (DHC) in Japan’s major cities are required to further lower their carbon emission. This study proposes to supply zero-carbon steam from a nearby waste incineration plant to the DHCs in the center of Yokohama, Japan’s second largest metropolis by constructing a pipeline between them. To maximize environmental effects of the project, efficient cogenerations will also be integrated extending low carbon heat supply to large buildings along the pipeline. Construction cost of five alternative pipeline routes, revenue from steam sales and the environmental value of reduced CO2 emission were estimated. Then the loan repayment period was calculated to figure out how to finance and manage the project. Because statistical data are used to calculate heat load, actual primary energy consumption and reduction of CO2 emission may differ. Also, without a detailed field survey, assumed construction cost may not correspond to the actual amount to be financed. From the study it became clear that steam pipeline with cogeneration will reduce 3.6 PJ of primary energy use and 300,000 tons of CO2 emission annually. The project will become feasible with loan repayment period of 8 and 10 years with and without subsidy by minimizing the construction cost.