Institution of Gas Engineers & Managers

With the world facing the twin pressures of a warming climate and an ever-increasing amount of waste it is becoming increasingly clear that we need to rethink the way we generate energy and use materials. Despite growing awareness our energy systems are still largely dependent on fossil fuels and characterized by a linear ‘take-make-dispose’ model. This leaves us vulnerable to supply disruptions rising greenhouse gas emissions and the depletion of critical raw materials. Hydrogen is emerging as a potential carbonfree energy vector that can overcome both challenges if it is produced sustainably from renewable sources. This study reviews hydrogen production from a circular economy perspective considering industrial agricultural and municipal solid waste as a resource rather than a burden. The focus is on the reuse of waste as a catalyst or catalyst support for hydrogen production. Firstly the role of hydrogen as a new energy carrier is explored along with possible routes of waste valorization in the process of hydrogen production. This is followed by an analysis of where and how catalysts from waste can be utilized within various hydrogen production processes namely those based on using fossil fuels as a source biomass as a source and electrocatalytic applications.

This research models a 20 MW PEM hydrogen plant. PEM units operate in the 60 to 80 ◦C range based on their location and size. This study aims to recover the waste heat from PEM modules to enhance the efficiency of the plant. In order to recover the heat two systems are implemented: (a) recovering the waste heat from each PEM module; (b) recovering the heat from hot water to produce electricity utilizing an organic refrigerant cycle (ORC). The model is made by ASPEN® V14. After modeling the plant and utilizing the ORC the module is optimized using Python to maximize the electricity produced by the turbine therefore enhancing the efficiency. The system is a closed-loop cycle operating at 25 ◦C and ambient pressure. The 20 MW PEM electrolyzer plant produces 363 kg/hr of hydrogen and 2877 kg/hr of oxygen. Based on the higher heating value of hydrogen the plant produces 14302.2 kWh of hydrogen energy equivalents. The ORC is maximized by increasing the electricity output from the turbine and reducing the pump work while maintaining energy conservation and mass balance. The results show that the electricity power output reaches 555.88 kW and the pump power reaches 23.47 kW.

Green hydrogen is gaining global attention as a zero-carbon energy carrier with the potential to drive sustainable energy transitions particularly in regions facing rising fossil fuel costs and resource depletion. In sub-Saharan Africa financing mechanisms and structured off-take agreements are critical to attracting investment across the green hydrogen value chain from advisory and pilot stages to full-scale deployment. While substantial funding is required to support a green economic transition success will depend on the effective mobilization of capital through smart public policies and innovative financial instruments. This review evaluates financing mechanisms relevant to sub-Saharan Africa including green bonds public–private partnerships foreign direct investment venture capital grants and loans multilateral and bilateral funding and government subsidies. Despite their potential current capital flows remain insufficient and must be significantly scaled up to meet green energy transition targets. This study employs a mixed-methods approach drawing on primary data from utility firms under the H2Atlas-Africa project and secondary data from international organizations and the peer-reviewed literature. The analysis identifies that transitioning toward Net-Zero emissions economies through hydrogen development in sub-Saharan Africa presents both significant opportunities and measurable risks. Specifically the results indicate an estimated investment risk factor of 35% reflecting potential challenges such as financing infrastructure and policy readiness. Nevertheless the findings underscore that green hydrogen is a viable alternative to fossil fuels in subSaharan Africa particularly if supported by targeted financing strategies and robust policy frameworks. This study offers practical insights for policymakers financial institutions and development partners seeking to structure bankable projects and accelerate green hydrogen adoption across the region.

The increasing global energy demand and the transition toward sustainable energy systems have highlighted the importance of energy storage technologies by ensuring efficiency reliability and decarbonization. This study reviews chemical and thermal energy storage technologies focusing on how they integrate with renewable energy sources industrial applications and emerging challenges. Chemical Energy Storage systems including hydrogen storage and power-to-fuel strategies enable long-term energy retention and efficient use while thermal energy storage technologies facilitate waste heat recovery and grid stability. Key contributions to this work are the exploration of emerging technologies challenges in large-scale implementation and the role of artificial intelligence in optimizing Energy Storage Systems through predictive analytics real-time monitoring and advanced control strategies. This study also addresses regulatory and economic barriers that hinder widespread adoption emphasizing the need for policy incentives and interdisciplinary collaboration. The findings suggest that energy storage will be a fundamental pillar of the sustainable energy transition. Future research should focus on improving material stability enhancing operational efficiency and integrating intelligent management systems to maximize the benefits of these technologies for a resilient and low-carbon energy infrastructure.

The burgeoning adoption of photovoltaic and wind energy has limitations of volatility and intermittency which hinder their application. Electro-hydrogen coupling energy storage systems emerge as a promising solution to address this issue. This technology combines renewable energy power generation with hydrogen production through water electrolysis and hydrogen fuel cell power generation effectively enabling the consumption and peak load management of renewable energy sources. This paper presents a power system with a 10 kW photovoltaic system and lithium battery energy storage system designed for hydrogen-electric coupled energy storage validated through the physical experiments. The results demonstrate the system's effectiveness in mitigating the impact of randomness and volatility in photovoltaic power generation. Moreover the energy management system can adjust bus power based on load demand. Testing the system in the absence of photovoltaic power generation reveals its capability to supply energy to the load for three hours with a minimum operating load power of 3 kW even under weather conditions unsuitable for photovoltaic power generation. These findings showed the potential of electro-hydrogen coupling energy storage systems in addressing the challenges associated with renewable energy integration paving the way for a reliable and sustainable energy supply.

The hydrogen fuel quality is critical to the efficiency and longevity of fuel cell electric vehicles (FCEVs) with ISO 14687:2019 grade D establishing stringent impurity limits. This study compared two different sampling techniques for assessing the hydrogen fuel quality focusing on the National Physical Laboratory hydrogen direct sampling apparatus (NPL DirSAM) from a 35 MPa heavy-duty (HD) dispenser and qualitizer sampling from a 70 MPa light-duty (LD) nozzle both of which were deployed on the same day at a local hydrogen refuelling station (HRS). The collected samples were analysed as per the ISO 14687:2019 contaminants using the NPL H2-quality laboratory. The NPL DirSAM was able to sample an HD HRS demonstrating the ability to realise such sampling on an HD nozzle. The comparison of the LD (H2 Qualitizer sampling) and HD (NPL DirSAM) devices showed good agreement but significant variation especially for sulphur compounds non-methane hydrocarbons and carbon dioxide. These variations may be related to the HRS difference between the LD and HD devices (e.g. flow path refuelling conditions and precooling for light duty versus no precooling for heavy duty). Further study of HD and LD H2 fuel at HRSs is needed for a better understanding.

In an effort to bridge the gap between academic research and industrial application this study investigates the integration potential of steam methane reforming and Co-electrolysis for the efficient conversion of refinery offgases into high-purity syngas. Experimental work was conducted under conditions representative of industrial environments using platinum- and nickel-based catalysts in steam reforming to assess methane conversion and H2 /CO ratio at varying temperatures and gas hourly space velocities (GHSV). Co-electrolysis was evaluated in solid oxide electrolysis cells (SOECs) across a range of gas compositions (H2O/CO2 /H2 /CO) including pure CO2 electrolysis as a strategy for pre-electrolysis hydrogen removal. Electrochemical performance was analyzed using impedance spectroscopy distribution of relaxation times (DRT) and current–voltage characterization. Results confirm the superior stability and performance of the Pt catalyst under high-throughput conditions while Ni-based systems were more sensitive to operational fluctuations. In the SOEC increased H2O content accelerated reaction kinetics whereas CO2 concentration governed polarization resistance. To enable optimal SOEC operation the addition of steam downstream of the reformer is proposed as a means of adjusting the reformate composition. The findings demonstrate that tuning reforming and electrolysis conditions in tandem offers a promising route for sustainable syngas production using renewable electricity. This work establishes a foundation for further development of integrated thermo-electrochemical systems tailored to industrial gas streams.

Demand for hydrogen is expected to increase in the coming years to defossilize hard-to-abate sectors. In the European Union the question remains in which quantities and at what cost hydrogen can be produced to satisfy the growing demand. This paper applies different approaches to model costs and potentials of off-grid hydrogen production within the European Union. The modeled approaches distinguish the effects of different spatial and technological resolutions on hydrogen production potentials costs and prices. According to the results the hydrogen potential within the European Union is above 6800 TWh. This figure far surpasses the expected demand range of 1423 to 1707 TWh in 2050. The cost of satisfying the demand exceeds 100 billion euro at marginal costs of hydrogen below 85 euro per megawatt-hour. Additionally the results show that an integrated European Union market would reduce the overall system costs notably compared to a setup in which each country covers its own hydrogen demand domestically. Just a few countries would be able to supply the entire European Union’s hydrogen demand in the case of an integrated market. This finding leads to the conclusion that an international hydrogen infrastructure seems advantageous.

Hydrogen storage in depleted gas reservoirs triggers geochemical and microbiological reactions at the caprockreservoir interface yielding significant implications on storage integrity. Acetogenesis is a microbial reaction observed during underground hydrogen storage (UHS) that produces acetate and converts it into acetic acid under protonation potentially impacting the UHS process integrity. For the first time this research explores the impact of the acetic acid + brine + caprock reaction on shale caprock mineralogy microstructure and physicochemical properties where this preliminary study has been conducted under ambient conditions to obtain an initial assessment of the impact. A comprehensive mineralogical and micro-structural characterization including scanning electron microscopy (SEM) energy dispersive X-ray spectroscopy (EDS) X-ray fluorescence (XRF) Xray diffraction (XRD) micro-computed tomography (micro-CT) and inductively coupled plasma mass spectrometry (ICP-MS) have been conducted to assess the mineralogical and microstructural changes in shale specimens saturated with brine solutions with a range of acetic acid percentages (5 % 10 % and 20 %) to find the maximum possible impact. According to the conducted mineralogical analysis (EDS XRF and XRD) there is a significant primary mineral dissolution during the acetic acid interaction where calcite and dolomite are the predominant minerals dissolved evidencing the significant impact of the acetic acid reaction on carbonate-rich caprock systems during UHS. However secondary mineral precipitation happened at high acidic concentrations (20 %). Interestingly other common minerals in reservoir rocks (e.g. mica pyrite) did not demonstrate rapid interactions with acetic acid compared to carbonates. The impact of these mineralogical changes on the caprock microstructure was then investigated through SEM and micro-CT and the results demonstrate substantial enhancements in porosity and microcracks in the rock matrix due to the calcite and dolomite dissolutions despite some microcracks being closed by secondary precipitations. This preliminary study evidences the significant impact of acidification on caprock integrity which may occur during the acetogenesis reaction in UHS environments. These effects should be carefully considered in field UHS projects to eliminate the risks.

This research presents a hierarchically synchronized Multi-Energy System (MES) designed for regional communities incorporating a network of small-scale Integrated Energy Microgrids (IEMs) to augment efficiency and collective advantages. The MES framework innovatively integrates energy complementarity pairing algorithms with efficient iterative optimization processes significantly curtailing operational expenditures for constituent microgrids and bolstering both community-wide benefits and individual microgrid autonomy. The MES encompasses electricity hydrogen and heat resources while leveraging controllable assets such as battery storage systems fuel cell combined heat and power units and electric vehicles. A comparative study of six IEMs demonstrates an operational cost reduction of up to 26.72% and a computation time decrease of approximately 97.13% compared to traditional methods like ADMM and IDAM. Moreover the system preserves data privacy by limiting data exchange to aggregated energy information thus minimizing direct communication between IEMs and the MES. This synergy of multi-energy complementarity iterative optimization and privacy-aware coordination underscores the potential of the proposed approach for scalable community-centered energy systems.