Abstract
Household cogeneration systems have been increasingly utilized for energy saving; however, their energy-saving effect in Japan is not necessarily sufficient due to their operational restriction that electricity generated by them cannot be transmitted to commercial electric power systems due to the regulation. To relax the restriction, the authors propose power interchange operation of multiple household gas engine cogeneration units and investigate its feasibility from the energy-saving viewpoint by an optimization approach. In this power interchange operation, a micro-grid using the units is constructed in a housing complex; electricity generated by them is shared among households without transmitting to a commercial electric power system outside the housing complex so that the operating time of these units may increase. To evaluate the energy-saving effect of the power interchange operation, a numerical analysis of operational strategies by the mixed-integer linear programming is conducted for ten households and three types of household energy supply configurations: the power interchange operation of the gas engine cogeneration units, a stand-alone operation of each gas engine cogeneration unit, and conventional energy supply system without the gas engine cogeneration unit. A computational result clarifies the advantage of the power interchange operation from the energy-saving viewpoint over the other energy supply configurations.
