A power smoothing control method for a photovoltaic generation system using a water electrolyzer and its filtering characteristics

Abstract

This paper proposes a novel power smoothing control method for a photovoltaic generation (PV) system using a water electrolyzer (ELY). This method realizes that the long-period components of the PV power fluctuation are supplied to the power grid and the short-period components of the PV power fluctuation are supplied to the ELY. The power supplied to the ELY is converted to hydrogen for fuel cell vehicles. The results of the power smoothing control method are evaluated in terms of the power in the load frequency control (LFC) band and the ability of generating hydrogen. Furthermore, filtering characteristics of the proposed method are clarified. As the result, the proposed method has reduced the power in LFC band by 83.7% compared to the PV power without the power smoothing control. The filter characteristics of the proposed method have shown that fluctuating components with periods less than 1000 seconds, in which the step voltage regulator does not perform, can be sufficiently eliminated from the PV power fluctuation components. When applying the proposed method for a PV system rated at 800 kW, the ability of generating hydrogen was about 2.30% of the hydrogen required for one hydrogen station. K E Y W O R D Shydrogen storage, load frequency control, photovoltaic generation, power smoothing control, water electrolyzer Electr Eng Jpn. 2019;206:25-32.

A Coordinated Control Method for Integrated System of Wind Farm and Hydrogen Production: Kinetic Energy and Virtual Discharge Controls

“…Nowadays, hydrogen is also spotlighted as an alternative source to fossil fuels because of environmental problems [2], [12]. Household and industrial fuel cells (FCs), fuel cell vehicles (FCVs), hydrogen powered heavy-duty trucks, and hydrogen stations for the FCVs have been developed as applications of hydrogen energy [2], [13]- [16]. Moreover, the hydrogen can be converted to other useful chemicals such as methane by blending the hydrogen with CO 2 [2].…”

“…There exist two types of systems composed of the HPS and the REPG, such as the WF, i.e., stand-alone systems [20]- [23] and grid-connected systems [11], [12], [16], [24]- [30]. In the stand-alone system where the HPS and the WF are disconnected from the grid, hydrogen can be produced without considering the power quality in the power system.…”

“…In these methods, the combination of HPS and FC behaves like an ESS because the HPS produces hydrogen by consuming power, and the FC generates power by consuming hydrogen. However, a part of electrical and hydrogen energies is wasted when the hydrogen produced by the HPS is reconverted to the power in the FC to smooth the WF output [16]. In addition, if hydrogen is used in the FC in order to smooth the WF output, it is challenging to store hydrogen for applications such as FCVs.…”

Study on operation in microgrid including hydrogen supplying equipment for contributing power system operation

“…Main demand‐side resources include heat‐pump water heaters, 2 water transfer pumps, 3,4 and batteries 5–7 . In addition, much attention has been drawn lately to power‐to‐gas (P2G) technology that converts electricity into hydrogen 8–12 . These studies on P2G consider schemes combining water electrolyzers, fuel cells, and so on.…”

“…These studies on P2G consider schemes combining water electrolyzers, fuel cells, and so on. with intermittent renewable power sources 8 and systems configured of microgrids (MG) supplemented with batteries or other energy storage 9–12 ; in so doing, P2G equipment and operation methods are aimed at output fluctuation suppression in intermittent renewable power sources 8–11 or utilization of surplus power 12…”