Assessment of CO2 Emissions Reduction Potential by Using an Optimization Model for Regional Energy Supply Systems

Abstract

The introduction of efficient energy systems, such as distributed co-generation systems, is expected to contribute to the development of effective measures for CO2 emission reduction in the commercial and residential sector. However, it has been pointed out that co-generation systems may not be effective measures for CO2 emission reduction if the electricity and heating demand ratio in the supplied region does not match the electricity and heat supply ratio of the installed co-generation system. Regional energy demand is expected to vary with many factors such as the types of buildings, total floor area and the meteorological conditions in the region. Regional energy supply systems should be optimized so as to meet the regional energy demands while minimizing the total costs of the system. A prototype model for optimizing regional energy supply systems in a city was developed. This model calculates the energy demand in a region and then finds the combination of energy supply systems that meets a required CO2 emission limit with minimum cost. Assessment of installing energy supply systems around Shinagawa area in Tokyo was carried out, where waste heat from sewerage and garbage incineration is expected to be available. In this assessment, costs and CO2 emissions were estimated when the energy supply systems were installed. It concludes that 17% of CO2 emissions from energy supply could be reduced with the same annual total cost as the current combination of energy supply systems in the Shinagawa area. Also, increasing the power generation efficiency of co-generation systems is effective for further reduction of CO2 emissions.