Evaluation of the Possibility of Reducing CO₂ Emission from Residential Buildings in Cold Districts of Japan by Employing an Micro Gas Turbine Co-Generation System

Abstract

Introducing a co-generation system is an effective choice for reducing energy derived CO₂ emissions and operating costs for the residential and commercial sectors. In this paper, the possibilities of CO₂ emission and operating cost reductions were investigated for the case of a micro gas turbine co-generation system being introduced into a 33 household apartment building located in Sapporo, one of the coldest districts in Japan, which demands a lot of energy in winter for hot-water supply and heating.
The results were compared with that of the existing system which is composed of an electricity grid and hot water boilers. The CO₂ emissions and operating costs of the co-generation system varied according to the ratio of electricity supply from the grid and MGT, MGT generation efficiencies and the season of the year. Using an MGT with an electricity generation efficiency of 35%, a reduction of 10% (23.4 tonne-CO₂/y) of CO₂ emissions and 9.4% (433ky) of operating costs could be attained compared with the existing system. In the case of a generation efficiency of 30%, a reduction of 3.4 tonne-CO₂/y is expected at the same level of operating cost as the existing system. But in the case of a generation efficiency of 25%, there was no signifi-cant reduction in CO₂ emission.