Abstract
The purpose of this study is to design an optimal energy system for an office building in a cold region in Hokkaido. In this research, the energy system is realized by the interconnection of photovoltaics and the cogeneration of electricity and heat by gas engine generator or solid oxide fuel cell (SOFC). We performed the optimization of the energy system from economic and power quality points of view. Results show that the introduction of the co-generation system by the SOFC is cheaper than the conventional system. Also, if we want to reduce the frequency variations for an increasing capacity of the photovoltaics, we should increase the inertia constant of the flywheel linearly.
