Institution of Gas Engineers & Managers

The renewable hydrogen economy is recognized as an integral solution for decarbonizing energy sectors. However high costs have hindered widespread deployment. One promising way of reducing the costs is optimization. Optimization generally involves finding the configuration of the renewable generation and hydrogen system components that maximizes return on investment. Previous studies have included many aspects into their optimisations including technical parameters and different costs/socio-economic objective functions however there is no clear best-practice framework for model development. To address these gaps this critical review examines the latest development in renewable hydrogen microgrid models and summarises the best modeling practice. The findings show that advances in machine learning integration are improving solar electricity generation forecasting hydrogen system simulations and load profile development particularly in data-scarce regions. Additionally it is important to account for electrolyzer and fuel cell dynamics rather than utilizing fixed performance values. This review also demonstrates that typical meteorological year datasets are better for modeling solar irradiation than first-principle calculations. The practicability of socio-economic objective functions is also assessed proposing that the more comprehensive Levelized Value Addition (LVA) is best suited for inclusion into models. Best practices for creating load profiles in regions like the Global South are discussed along with an evaluation of AI-based and traditional optimization methods and software tools. Finally a new evidence-based multi-criteria decision-making framework integrated with machine learning insights is proposed to guide decision-makers in selecting optimal solutions based on multiple attributes offering a more comprehensive and adaptive approach to renewable hydrogen system optimization.

Hydrogen is a crucial energy carrier for the Clean Energy Sustainable Development Goals and the just transition to low/zero-carbon energy. As a top CO2-emitting country hydrogen (especially green hydrogen) production in South Africa has gained momentum due to the availability of resources such as solar energy land wind energy platinum group metals (as catalysts for electrolysers) and water. However the demand for green hydrogen in South Africa is insignificant which implies that the majority of the production must be exported. Despite the positive developments there are unclear matters such as dependence on the national electricity grid for green hydrogen production and the cost of transporting it to Asian and European markets. Hence this study aims to explore opportunities for economic expansion for sustainable production transportation storage and utilisation of green hydrogen produced in South Africa. This paper uses a thematic literature review methodology. The key findings are that the available renewable energy sources incentivizing the green economy carbon taxation and increasing the demand for green hydrogen in South Africa and Africa could decrease the cost of hydrogen from 3.54 to 1.40 €/kgH2 and thus stimulate its production usage and export. The appeal of green hydrogen lies in diversifying products to green hydrogen as an energy carrier clean electricity synthetic fuels green ammonia and methanol green fertilizers and green steel production with the principal purpose of significant energy decarbonisation and economic and foreign earnings. These findings are expected to drive the African hydrogen revolution in agreement with the AU 2063 agenda.

A lot of countries have recently published updated hydrogen strategies with many of them increasing and renewing their commitment. In parallel corresponding policy mechanisms are increasingly coming into focus with the first ones already having awarded funding contracts to projects and construction being underway. However these policies are usually translated from renewable energy policy without considering the specific risks and uncertainties spillovers and positive externality of operating grid-conducive electrolyzers in electricity grids which are increasingly subjected to electricity supply volatility from renewables. This article details how different aspects of a dedicated hydrogen policy can address the technology’s specific issues from an economic perspective namely funding provision market and technology risk mitigation and the complex relationship with further actors in electricity markets. Results show that compared to renewable energy policy mechanisms need to emphasize the input side more strongly as price risks and intermittency from electricity markets are more prominent than from hydrogen markets. Also it proposes a targeted mechanism to capture the positive externality of mitigating excess electricity in the grid while keeping investment security high. Economic policy should consider such approaches before scaling support and avoiding the design shortcomings experienced with early RE policy.

This paper focuses on the critical role of long-duration energy storage (LDES) technologies in facilitating renewable energy integration and achieving carbon neutrality. It presents a systematic review of four primary categories: mechanical energy storage chemical energy storage electrochemical energy storage and thermal energy storage. The study begins by analyzing the technical advantages and geographical constraints of pumped hydro energy storage (PHES) and compressed air energy storage (CAES) in high-capacity applications. It then explores the potential of hydrogen and synthetic fuels for long-duration clean energy storage. The section on electrochemical energy storage highlights the high energy density and flexible scalability of lithium-ion batteries and redox flow batteries. Finally the paper evaluates innovative advancements in large-scale thermal energy storage technologies including sensible heat storage latent heat storage and thermochemical heat storage. By comparing the performance metrics application scenarios and development prospects of various energy storage technologies this work provides theoretical support and practical insights for maximizing renewable energy utilization and driving the sustainable transformation of global energy systems.

Ammonia is a versatile energy carrier without carbon emissions that can be used for power generation. In this article a techno-economic analysis has been done to predict the levelized cost of electricity production using gas turbines with clean fuel in Iran. In the technical discussion the analysis of different scenarios of ammonia and hydrogen fuel composition ratio was done and by keeping the turbine inlet temperature to the same gas turbine as the SGT5-2000E turbine the output power in different fuel ratios is around 192.8 to 229.0 MW was variable and reached the maximum value in some proportions. Also in the economic discussion the effects of fuel cost and interest rate parameters were investigated sensitivity analysis was performed on different combined ratios of ammonia and hydrogen in fuel and an economic analysis of the ideal ratio was conducted. The price of ammonia fuel was calculated from 222 $/ton to 2000 $/ton and the levelized cost of electricity production changed from 91.7 $/MWh to 673.4 $/MWh. Additionally an economic comparison was made between the utilization of ammonia-hydrogen and natural gas fuels. This alternative fuel can be a promising way to produce power without carbon emissions and suitable storage for renewables.

This paper presents a thorough initial evaluation of hydrogen gaseous storage and pipeline infrastructure emphasizing health and safety protocols as well as capacity considerations pertinent to industrial applications. As hydrogen increasingly establishes itself as a vital energy vector within the transition towards low-carbon energy systems the formulation of effective storage and transportation solutions becomes imperative. The investigation delves into the applications and technologies associated with hydrogen storage specifically concentrating on compressed hydrogen gas storage elucidating the principles underlying hydrogen compression and the diverse categories of hydrogen storage tanks including pressure vessels specifically designed for gaseous hydrogen containment. Critical factors concerning hydrogen gas pipelines are scrutinized accompanied by a review of appropriate compression apparatus types of compressors and particular pipeline specifications necessary for the transport of both hydrogen and oxygen generated by electrolysers. The significance of health and safety in hydrogen systems is underscored due to the flammable nature and high diffusivity of hydrogen. This paper defines the recommended health and safety protocols for hydrogen storage and pipeline operations alongside exemplary practices for the effective implementation of these protocols across various storage and pipeline configurations. Moreover it investigates the function of oxygen transport pipelines and the applications of oxygen produced from electrolysers considering the interconnected safety standards governing hydrogen and oxygen infrastructure. The conclusions drawn from this study facilitate the advancement of secure and efficient hydrogen storage and pipeline systems thereby furthering the overarching aim of scalable hydrogen energy deployment within both energy and industrial sectors.

We investigate the challenges and options for repurposing existing natural gas pipelines for hydrogen transportation. Challenges of re-purposing are mainly related to safety and due to the risk of hydrogen embrittlement of pipeline steels and the smaller molecular size of the gas. From an economic perspective the lower volumetric energy density of hydrogen compared to natural gas is a challenge. We investigate three pipeline repurposing options in depth: a) no modification to the pipeline but enhanced maintenance b) use of gaseous inhibitors and c) the pipe-in-pipe approach. The levelized costs of transportation of these options are compared for the case of the German Norddeutsche Erdgasleitung (NEL) pipeline. We find a similar cost range for all three options. This indicates that other criteria such as the sunk costs public acceptance and consumer requirements are likely to shape the decision making for gas pipeline repurposing.

The future of energy is of global concern with hydrogen emerging as a potential solution for sustainable energy development. This paper provides a comprehensive analysis of the current hydrogen energy landscape its potential role in a decarbonized future and the hurdles that need to be overcome for its wider implementation. The first elucidates the opportunities hydrogen energy presents including its potential for decarbonizing various sectors in addition addresses the challenges that stand in the way of hydrogen energy large-scale adoption. The obtained results provide a comprehensive overview of the hydrogen energy horizon emphasizing the need to balance opportunities and challenges for its successful integration into the global energy landscape. It highlights the importance of continued research development and collaboration across sectors to realize the full potential of hydrogen as a sustainable and low-carbon energy carrier.

Proton exchange membrane electrolyzer cell (PEMEC) will play a central role in future power-to-H2 plants. Current research focuses on the materials and operation parameters. Setting up experiments to explore operational accident scenarios about safety feasibility is not always practical. This paper focuses on building mathematical and prediction models of hydrogen and oxygen mixing scenarios of PEMEC. A mathematical model of the PEMEC device was customized in the Aspen Custom Model (ACM) software and integrated various critical Physico-chemical phenomena as the original data set for the prediction model. The results of the mathematical simulation verified the experimental results. The prediction model proposes an artificial neural network (ANN) framework to predict component distribution in the gas stream to prevent hydrogen-oxygen explosion scenarios. The presented approach by training ANN to 1000 sets of hydrogen-oxygen mixing simulation data from ACM is applicable to bypass tedious and non-smooth systems of equations for PEMEC.

This paper reports on the experimental data analysis and numerical results carried out by algorithms in order to meet the provisions of Industry 4.0 in the field of research of Solid Oxide Fuel Cell/Electrolyzer. A performance mapping of the analyzed SOFC/SOE systems is developed in order to enhance system efficiency when it is fed by biofuels. The analyses concern the main operative parameters such as pressure temperature fuel compositions and other main system parameters such as fuel and oxidant utilization factors and the recirculation of anode exhaust stream gas.