Hydrogen storage for the energy transition: an overview

In the past decades the emissions of greenhouse gasses contributed to the global warming, a product of the emission of the fossil fuels. To solve this problem the governments agreed to implement the renewable energy production, exploiting resources such as solar, wind, geothermal and ocean. These resources could reduce the greenhouse gasses emissions playing a main role in the goal to reach the carbon neutrality by the 2050. These types of energy come out of the nature and so is not possible to plan the production and modelling it as required by the energy demand. The only way the production can meet the demand is through energy storage or energy carriers, like hydrogen. In fact, with the renewable energy the pollution can be cut significantly, but it exposes the user to the risk of fluctuations in the production in the moments in which these resources are not present. The trends seem to indicate the future dependency on energy storage or energy carriers. With the surplus of the production it can be produced green hydrogen which can be burnt when the energy is needed, in a reaction that doesn’t pollute and has in the water its main product. The hydrogen itself, in this pathway is not considered a source of energy but and energy carrier, since the energy obtained by its combustion is less than the one used to produce it. In this panorama there is a large amount of hydrogen that needs to be stored and much storage capacity, that was used for storing natural gas, that will be unutilized, as far as the gas production will be cut to meet the climate goals. The aim of this project is to investigate the possibility to use the same storage facilities used for the natural gas to store hydrogen, reducing the cost of building or invent new solutions. To study the feasibility of this process is important to understand how men have stored the natural gas so far, analyzing the different kinds of facilities, the physics and the chemistry that stand behind this process and the real storage capacity suitable for this solution. In this paper is given an overview who aims to lead to a complete knowledge of the main parameters and solutions available for this purpose, along with a detailed background of the natural gas storage and an analysis of the challenges that must be overtaken to store safely and correctly hydrogen. In the process will be performed also an economic analysis, that together with the aspects indicated before can give a complete overview of these solutions.