Assessment of PV´s and CGS´s ability for reducing CO2 emission viewed from whole energy system in Japan

This paper discusses the ability of photovoltaic power generation systems (PV) and cogeneration system (CGS) to reduce CO₂ emissions of the whole energy system in Japan. The authors constructed a simulation model to calculate the optimum generation mix in 2010, where PV systems and CGS are assumed as a substitutional power source of utility´s combined-cycle generator fueled by LNG (CC-LNG). Using the model, they evaluated the reduction of total CO₂ emission by the introduction of PV system or CGS. In the case of the PV systems, the total amount of CO₂ reduction is smaller than the expected value because the annual load factor of PV systems is much lower than that of CC-LNG and the shortage of electricity supply is mainly met by the utility´s current generators. In the case of CGS, the total amount of CO₂ reduction is larger than that in the case of PV systems