Pabon, Juan Jose GarciaWang, JayChamanehpour, ElhamSalami, DariushKhosravi, Ali2025-11-282025-11-282025-11-16International Journal of Hydrogen Energy, ISSN: 0360-3199 (Print); 1879-3487 (Online), Elsevier. doi: 10.1016/j.ijhydene.2025.1525570360-31991879-3487http://hdl.handle.net/10292/20229The data center sector is rapidly expanding due to the growing demand for cloud storage services, artificial intelligence applications, and other digital technologies. The electricity consumption required to power servers, and their cooling systems are significantly high. Consequently, data centers must align with global carbon reduction goals by adopting renewable energy sources. However, the intermittency of renewable energy sources conflicts with one of the core requirements of data centers: continuous and reliable 24/7 operation. To address this challenge, energy storage systems are essential. While batteries represent the most mature technology, larger-scale systems require complementary storage solutions. This paper presents a transient model developed in Simscape of Matlab of a green data center (1 MW size) powered entirely by renewable energy, integrating both battery storage and green hydrogen. An alkaline electrolyzer is used to convert excess photovoltaic solar energy into hydrogen, which is stored in a tank at a maximum pressure of 30 bar. During periods without solar availability, a PEM fuel cell utilizes the stored hydrogen to generate electricity, working in tandem with the battery system to ensure uninterrupted operation of the data center. Furthermore, the heat extracted from the data center by a heat pump, along with the heat generated by the electrolyzer and fuel cell, is recovered and integrated into a district water heating system. This strategy enhances the overall energy efficiency of the system. The results show that the data center consumes 24 MWh/day, with an additional 12 MWh/day required for the heat pump. The PV panels supply 64 MWh/day, allowing the electrolyzer to consume 18.4 MWh/day for hydrogen production, while the fuel cell provides 7.6 MWh/day to cover nighttime demand. Despite the hydrogen system's lower electrical efficiency (40.6 %), integration of waste heat recovery increases its effective energy efficiency to 82.3 %, approaching battery efficiency (85.9 %). It is noted that the system's useful Total Energy Utilization Factor exceeds 115 %, primarily due to the recovered heat being effectively utilized in the district heating network.This is the Author's Accepted Manuscript of an article published in the International Journal of Hydrogen Energy © Elsevier. The version of record is available at DOI: 10.1016/j.ijhydene.2025.15255703 Chemical Sciences09 EngineeringEnergy34 Chemical sciences40 EngineeringDynamic simulationData centerGreen hydrogenSector couplingPower-to-XDistrictHeatingJournal ArticleOpenAccess10.1016/j.ijhydene.2025.152557