Hydrogen Storage in Porous Rocks: A Bibliometric Analysis of Research Trends

Abstract

Currently, there is an increasing number of research studies on underground storage of hydrogen in porous rocks (aquifers and depleted hydrocarbon fields). An important aspect of this process is the efficiency of hydrogen storage, which is defined as the correct operation of a storage facility (the ability to inject and withdraw an appropriate quantity of gas) and the safety of storage, which is influenced by numerous factors, including geological factors. With an increasing number of publications, gathering knowledge and keeping track of scientific progress is becoming increasingly complex. In addition to the technical interdependence of the parameters analysed, there are also interrelationships between scientific publications addressing issues related to underground hydrogen storage in porous rocks. The aim of this paper is to analyse the literature on hydrogen storage efficiency in porous rocks and, on the basis of the analysis, to identify the most important research trends and issues relevant to their implementation. This article presents an analysis of publications indexed in the SCOPUS database. The analysis included publications that contained expressions related to the relevant search phrases in their title, abstract or keywords. The dynamics of changes in the interest of researchers on the problem of hydrogen storage in porous rocks and the distribution of studies by geographical location (countries) are presented. Based on an analysis of the number of citations, the most influential publications were identified. Using the VOSviewer version 1.6.19 software, clusters reflecting research sub-areas were identified based on co-occurrence analysis, such as geological and reservoir aspects, reservoir engineering aspects, hydrogeological aspects and petrophysical aspects. Bibliometric methods have great potential for performing quantitative confirmation of subjectively delineated research fields and/or examining unexplored areas. The literature on underground hydrogen storage in porous rocks has been growing rapidly since at least 2018, with researchers conducting their studies in four major research streams: geological and reservoir aspects, reservoir engineering aspects, hydrogeological aspects and petrophysical aspects.

Underground Gas Storage in Saline Aquifers: Geological Aspects

“…The remaining storage facilities are located in depleted oil fields-41-and rock caverns-3. In the analyzed years 2017-2021, there were 72 commercial underground gas storage projects in aquifers located worldwide (the number of projects per country is given in brackets) in Belarus (3), Belgium (1), Czech Republic (1), Denmark (1), France (10), Germany (3), Kazakhstan (2), Latvia (1), Russia (7), Spain (1), Ukraine (2), and the USA (51) (Figure 2). Working gas volume values for individual storage facilities range from 2 to 10,250 million m 3 , with an average of 656 million m 3 .…”

“…There are two types of H 2 storage: physical and chemical (material) methods. Hydrogen can be stored on the surface (in tanks and in natural gas grids) and underground in geological structures (physical method) [7]. Chemical hydrogen storage refers to the process of storing hydrogen through chemical reactions, typically involving compounds that can release or absorb hydrogen.…”