Dynamic Modeling of Hydrogen Systems for Grid Operations: Compression and Storage

Abstract

With the increasing penetration of intermittent renewable resources (e.g., solar and wind) into the power grid, hydrogen production from renewable electrolysis has gained more attention as a large-scale energy storage technology to meet the fluctuating grid demand and improve the resilience of the energy system. Accordingly, the development of economic, efficient and safe hydrogen storage technology is required. High-pressure gaseous hydrogen storage is currently the most suitable solution for long-duration storage due to its technical simplicity, reliability, energy efficiency as well as affordability [1]. Even though compressed hydrogen storage has a fast filling-releasing rate, the increase in the pressure and temperature of hydrogen in the storage tank leads to thermal stress and related safety concerns [2]. With this motivation, a complete system of hydrogen production via electrolysis and high-pressure hydrogen storage was developed. Different filling and releasing cycles and transient responses of the storage tank will be presented.A high-fidelity dynamic model of a Proton Exchange Membrane (PEM) electrolyzer was developed for hydrogen production from an intermittent renewable resource. A parallel multi-stage hydrogen compression system with cascaded filling configuration was modeled and designed. A non-adiabatic lumped dynamic model was developed for the storage tank and the heat conductivity within the tank wall was included. In addition, the thermal stress model was developed to estimate the storage tank stress transient. Different equations of state (e.g., Peng-Robinson or Modified Benedict-Webb-Rubin) were adopted to account for the non-ideal gas response of high-pressure gaseous hydrogen [3]. Under the steady-state condition of 510 kW power, 90 Nm3/hr (i.e., 7.92 kg/hr) of hydrogen can be produced and compressed up to the maximum pressure of 44 MPa. The full capacity of the storage tank would be reached after 72 hr.Different filling and releasing scenarios were implemented depending on the seasons and hydrogen fuel applications. The compressor duty as well as the storage tank pressure and temperature was monitored and controlled. The most effective and economical filling and releasing operation will be presented based on technical and economic analysis.[1] Li, Mengxiao, Yunfeng Bai, Caizhi Zhang, Yuxi Song, Shangfeng Jiang, Didier Grouset, and Mingjun Zhang. "Review on the research of hydrogen storage system fast refueling in fuel cell vehicle." International Journal of Hydrogen Energy 44, no. 21 (2019): 10677-10693.[2] Li, Ji-Qiang, No-Seuk Myoung, Jeong-Tae Kwon, Seon-Jun Jang, and Taeckhong Lee. "A Study on the Prediction of the Temperature and Mass of Hydrogen Gas inside a Tank during Fast Filling Process." Energies 13, no. 23 (2020): 6428.[3] Lemmon, Eric W., Marcia L. Huber, Daniel G. Friend, and Carl Paulina. Standardized Equation for Hydrogen Gas Densities for Fuel Consumption Applications1. No. 2006-01-0434. SAE Technical Paper, 2006.