P2G System Technology Development Aiming at Building a CO2-Free Hydrogen Society

Abstract

The government's "Basic Energy Plan" decided on April 11, 2014 has been decided to promote initiatives aimed at realizing "hydrogen society", a society that utilizes hydrogen in everyday life and industrial activities It was. Following this, the Ministry of Economy, Trade and Industry will formulate the "Hydrogen / Fuel Cell Strategy Roadmap" in June 2014 and aim to establish a CO2-free hydrogen supply system around the year 2040. According to the Government's "Long-Term Energy Supply and Demand Outlook" published in July 2015, the renewable energy ratio to total electricity generation in FY 2030 is estimated to be 22 to 24%. On the other hand, renewable energy has large output fluctuations due to the influence of the natural environment, and geographically unevenly, there are concerns such as suspension of connection to the transmission and distribution electric power network. One solution to this problem would be the Power-to-Gas system utilizing the conversion using electric power from renewable energy into hydrogen. The obtained hydrogen can reduce CO2 emissions by replacing fossil fuels in heating sector. At the Agency for Natural Resources and Energy, the report of the "CO2 Free Hydrogen Working Group" was compiled in March, In the report, technical issues such as low cost and high efficiency of various technologies including water electrolysis equipment, improvement of durability, improvement of utilization rate were taken as technical issues. In this research, we demonstrate technological development from hydrogen production using renewable energy to transportation, storage and use in the real society, and establish the basic technology for practical application of "Power to Gas system". The applicability of the water electrolyzer was confirmed by grasping the electrical characteristics of the water electrolyzer (the ability to absorb unstable power, responsiveness, etc.) from the data of the evaluation equipment. In addition, it was expected that 74% could be achieved with the year-round water electrolyzer system efficiency. In the future business model using the 1.5 MW PEM type water electrolyzer, the MEA performance for achieving the required system efficiency of 80.5% is based on the voltage efficiency has already been achieved. Assuming a system at the stage of practical use, we concluded that direct utilization for industrial use and utilization as a CO2-free fuel for the heat demand for industrial use are effective. In line with this conclusion, we have determined the specifications of a pure hydrogen boiler assumed as a hydrogen utilization device, by investigating the tolerance of fluctuations and the partial load operation in line with actual plant operation. ACKNOWLEDGEMENT This work was partially supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan.