Wind power generation and photovoltaic power generation fluctuate in power output according to wind and weather conditions, and it is concerned whether such fluctuation may influence power quality, such as frequency. HEPCO has proceeded with the deployment of renewable energy while evaluating its influence on electric power systems.
In this demonstration project, Sumitomo Electric and HEPCO will jointly install a large-scale storage battery at HEPCO’s primary substation, and test its performance as a solution to the output fluctuation of wind power and photovoltaic power. This project also intends to develop optimal control technologies. By combining our technologies and know-how, we intend to commit ourselves to expanding the further use of renewable energy.
1. Overview of the demonstration project
- (1) Place of installation
- HEPCO’s Minamihayakita Substation (Abira, Yufutsu District, Hokkaido)
- (2) Demonstration facilities
- Redox flow battery
Rated output: 15,000 kW
Storage capacity: 60,000 kWh
- (3) Test period
- Fiscal 2013 through fiscal 2017
(Construction is scheduled to be completed before the end of fiscal 2014 and the demonstration test will be conducted for the subsequent three years)
- (4) Objectives of the demonstration test
- Development of a frequency fluctuation suppression control method to use the storage battery as a frequency-adjusting power supply
- Development of an operating method dealing with surplus power supply by means of the storage battery (to provide regulation down)
- Redox flow battery performance evaluation
[Storage battery control diagram]
2. Overview of the redox flow battery
A redox flow battery charges and discharges electricity as the electrolyte that uses vanadium and other metal ions circulates. It consists of cell stacks for input and output, tanks for electrolyte storage, and pumps for electrolyte circulation.
As the redox flow battery can have great output and capacity, it can be used for various purposes in a power supply system, such as frequency fluctuation suppression and surplus power supply control (provision of regulation down).
The redox flow battery is currently demonstrated at the Yokohama Works and Osaka Works of Sumitomo Electric. Based on the achievements of these demonstration tests, we intend to introduce a storage battery with improved performance.
＜Major strengths of the redox flow battery＞
- Easy maintenance and extremely high safety.
- The electrodes and electrolyte do not deteriorate by charge and discharge cycles and can be used for a long time.
- The amount of stored electric power can be accurately monitored and controlled.
[Basic structure of the redox flow battery]
[Perspective drawing of the facility]
In the Minamihayakita Substation, a new building for exclusive use for the demonstration project of the battery is planned, in which electrolyte tanks will be installed on the first floor and cells stacks and heat exchangers on the second floor.
(Construction area: 5,000 m²: about four times as large as a gym at an elementary or junior high school)