Grid-Forming Services From Hydrogen Electrolyzers

Abstract

Hydrogen electrloyzers are power-to-gas storage devices that can facilitate large-scale integration of intermittent renewable sources into the future power systems. Due to their fast response and capability to operate in different loading conditions, they can be used as responsive loads providing support to AC grid during transients. This paper suggests taking one step further and using hydrogen electrolyzers to provide grid-forming services to the grid. As a result, the electrolyzer's role is elevated from supporting the grid (responsive load) to actively participating in forming voltage and frequency of the grid. The grid-forming capability of electrolyzer is linked to its hydrogen production constraints, which can potentially pose limitations on the gridforming services. Besides the grid-forming mode, two additional operating modes, i.e., DC voltage mode and constant power mode, are proposed to ensure a safe operation of the electrolyzer in case of adversary interaction between grid-forming operation and hydrogen production constraints. This paper also studies the impacts of grid-forming services on the electrolyzer's physical features such as hydrogen stack temperature and efficiency. Comprehensive simulations are conducted on a low-inertia test network whose topology is inspired by a portion of the transmission grid in South Australia to confirm the effectiveness of the proposed concept under various operational conditions of the electrolyzer and upstream AC grid. Moreover, the practical feasibility of the proposed control system is experimentally validated by conducting hardware-in-the-loop tests.

A review of electrolyzer-based systems providing grid ancillary services: current status, market, challenges and future directions

“…To evaluate the effectiveness of using electrolyzers to provide grid-forming services, Tavakoli et al (2023) conducted numerical analyses on a low-inertia test grid inspired by a portion of the transmission grid in southern Australia. In addition to the gridforming mode, to ensure the safe operation of the electrolyzer in case of adverse interaction between the grid-forming operation and hydrogen production constraints, the authors developed two other additional operating modes, such as the DC voltage and constant power modes, respectively.…”

Effect of a Large Proton Exchange Membrane Electrolyser on Power System Small-Signal Angular Stability

“…As a result, the number of hydrogen electrolysers connected to transmission power systems is increasing. Hydrogen electrolysers are electrochemical devices used to separate water molecules into hydrogen and oxygen by passing a DC current through them [1]. This DC current is proportional to the hydrogen production.…”

“…This DC current is proportional to the hydrogen production. There are different hydrogen electrolyser technologies, which range from small systems (kilowatts) to largescale systems (multiple megawatts) [1]. The most well-known technologies in industrial projects under development are alkaline electrolysers and proton exchange membrane (PEM) electrolysers [2].…”

“…Alkaline electrolyser technology, which is widely used today, is considered a mature technology in the industrial sector. Due to their advantages over alkaline electrolysers, such as high power density and cell efficiency, as well as fast dynamics, PEM electrolysers are in a period of great expansion and development for integration into power systems, including renewable energy production systems [1][2][3][4][5]. For this reason, PEM electrolyser technology is dealt with within this paper.…”

Performance Test of 1 kW PEM Fuel Cell System to Determine Its Empirical Model

“…Fuel cells have a big potential to be applied in renewable-energybased power generation. With electrolyzer, fuel cells can be operated either as grid-forming or grid-following generators to stabilize the voltage and frequency of a power grid 2,3) . Moreover, fuel cell electric vehicles (FCEVs) have been considered as one of the primary substitutes for internal combustion engines (ICEs) 4) and as a complementary technology of electric vehicles 5) for achieving the target of zero emissions in the transportation sector.…”