Combined heat and power (CHP) is crucial for promoting thorough energy conservation and advanced energy use, aimed toward greenhouse gas reduction. Solid oxide fuel cell (SOFC)-CHP is expected to be introduced as a measure against global warming and has been the focus of attention, and this study examined the effects of its introduction. This study introduces a linear programming evaluation model that can simulate optimized facility configuration and operation, based on the power supply and demand. The novelty of the proposed model is the consideration of geographic characteristics, which influences parameters dependent on gas transportation infrastructure and electricity. A sensitivity analysis was conducted considering the number of units and location of SOFC-CHP introductions in the National Capital Region of Japan. As a result, it was predicted that SOFC-CHP would likely begin to be introduced in areas where there is a large shadow price difference between electricity and gas at each node. The total power generation will decrease, as transmission and distribution losses decrease, owing to the diffusion of SOFC-CHP installed in the vicinity of demand. The widespread use of SOFC-CHP is an economically feasible CO2 emissions reduction pathway. These results will help assess the introduction of various distributed power sources in addition to SOFC-CHP to reduce CO2 emissions.