変動性再生可能エネルギー大量導入に伴う統合費用の評価方法に関する検討

抄録

Due to growing concerns over climate change, as well as to the recent cost declines, variable renewable energies (VREs), such as wind and solar PV, have seen rapid deployment over the past few years. High penetration of VREs, however, requires additional costs caused by the intermittency, e. g. those for grid expansion, for deploying power storage systems, and for power curtailment. Thus the total system cost becomes larger than the cost measured simply by the traditional metric known as the levelized cost of electricity (LCOE), which has long been used for estimating the economics of the power sector. This paper proposes a methodology to assess these additional “system integration costs”, as well as to decompose them into several subcategories, using two complementary mathematical optimization models. It also applies the methodology to Japan's power system in 2030, in the aim of obtaining insights into the key factors that determine the changes in the power sector under high penetration of VREs. The results show that in a case with a solar PV capacity of 64GW and a wind capacity of 10GW, the system integration cost divided by the total power supply amounts to 0.41JPY/kWh. Reduction in the load factors of conventional power generation facilities accounts for the largest part of the system integration cost at 0.30JPY/kWh, highlighting the need for appropriate policy measures that ensure the adequacy of power systems.