Cost analysis of stable electric and hydrogen energy supplies derived from 100% variable renewable resources systems

The purpose of this study was to evaluate the costs and specifications of 100% VRE (Variable Renewable Energy) systems that consist of VRE and energy storage systems. For that purpose, a model was developed to comprehensively analyze the costs and the specifications of 100% VRE systems. Using the model, the following results were obtained: (1) A hybrid storage system of battery and hydrogen storage that are optimally combined, as well as the optimal combination of solar and wind power, could reduce supply costs of electric energy. Concerning the hybrid storage system, the battery that operates with a daily cycle cooperates with the hydrogen storage that operates with a multiple day cycle, and; (2) multi-production systems that supply electric energy as well as hydrogen energy could reduce energy supply costs when an optimal combination of electric energy and hydrogen energy is achieved. However, the supply costs of stable electric energy as well as hydrogen energy from the 100% VRE systems are more expensive than the target costs in 2030 in Japan. In order to reduce the energy supply costs, it is necessary to reduce the costs of elemental technologies such as solar, wind power, battery, and hydrogen-related technologies. (c) 2021 Elsevier Ltd. All rights reserved.