Microgrid composed of three or more SOFC combined cycles without accumulation of electricity

Large-scale centralization of the power supply system, consisting mainly of nuclear power generation and thermal power generation, has been adopted in Japanese electrical power system. Because Japan's centralized power supply system has little accommodation for changes in load, the amount of renewable energy that can be introduced is restricted substantially. The percentage of renewable energy introduced in Japan in 2012 was 1.6%; if this were to include hydraulic power generation, the percentage would be less than 10%. Accordingly, this study proposes the development of a microgrid that responds to the changes in output from a large-scale solar power system by using load from the operation of three or more solid oxide fuel cell hybrid power systems (PGSSs), and controlling the number of PGSS units in response to the magnitude of load. A storage battery is not used for the microgrid, developed in this study, for controlling the change in output from renewable energy. The proposal of a system with an introductory high rate of renewable energy is the purpose of this study. The study clarified the method of system operation and the rate at which renewable energy can be introduced at the time of distributed installation of the developed microgrid, using three or more PGSSs to supply all the cities in the Hokkaido region of Japan. From the results of the analysis, the control achieved with the PGSS units was confirmed to be effective. Furthermore, according to meteorological data and our proposed microgrid, the power supplied by renewable energy over the entire Hokkaido region in 2012 reached 48% on February 14 (winter), 49% on July 15 (summer), and 45% on October 15 (moderate season).