Analysis of effective measures for power fluctuation mitigation of geographically distributed wind and solar power

Establishing sustainable and economical pathways for the deployment of variable renewable energy (VRE) is essential for reducing greenhouse gas emissions and increasing energy security. However, due to VRE power output fluctuations, high shares of VRE are associated with increases in surplus power generation, which increases the cost of power supply. This paper examines the effects of power fluctuation mitigation measures on the integration of high shares of VRE in power supply systems. The paper takes a systematic approach to evaluate the effects of the geographical distribution of VRE locations, the increase in transmission capacity, and the introduction of large-scale battery storage while increasing the VRE share. The methodology used in this analysis is a linear programming-based power supply mix model which was developed to optimize installed capacities and operation patterns of a power supply system with geographically distributed VRE locations by minimizing the total cost of power supply. The developed methodology is applied to the power supply system of Hokkaido, Japan, as a case study. The results demonstrate that VRE shares of up to 40 % can be achieved by geographically distributing the VRE locations with no increase in the total cost of the power supply. This is because the geographical distribution of VRE locations suppresses the increase in surplus power generation. Further, achieving 40 % to 60 % VRE shares only requires an increase in the power transmission capacity. However, for higher VRE shares from 60 % to 80 %, a combination of the geographical distribution of VRE locations, transmission capacity increase, and the introduction of power storage are required to effectively minimize the amount of surplus power generated.