2020 Volume 55 Issue 1 Pages 28-35
We propose a “hybrid energy storage system composed of electric and hydrogen energy storage systems” and perform verification tests for demonstrating that the hybrid energy storage system proposed is effective for improving the utilization rate of renewable energy and can be used for large-capacity emergency power sources that do not require external fuel procurement. Predicting the difference between solar power generation output and load power consumption using the Kalman filter, short-period fluctuation compensation using the power storage device, and long-period fluctuation compensation using the hydrogen storage system were effective for compensating the precise fluctuation of solar power generation output and load power consumption. The hydrogen release rate from a hydrogen storage alloy was improved by installing a buffer tank between a fuel cell and the hydrogen storage alloy. During 72-hr continuous operation tests assuming a long-term blackout due to a large-scale natural disaster, it was demonstrated that the DC bus voltage fluctuation due to sudden fluctuations in solar power generation output and load power consumption was suppressed to approximately 1.5% or less of the reference voltage (380 V).Therefore, it was proven that the hybrid energy storage system proposed is useful as a large-capacity emergency power source for water purification plants, and enables long-term highly accurate fluctuation compensation and a highly stable power supply.
