Green Hydrogen Production: Advances and Challenges

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.

Green Hydrogen is widely acknowledged as one of the important pillars for decarbonisation of hard-to-abate sectors and to transition the global economy to Net Zero. The current priority in the energy sector is to rapidly establish and scale a green Hydrogen based energy value chain that meets three core objectives: affordability, sustainability and security of supply, also referred to as ‘Energy Trinity’. Green hydrogen is produced from electrolysis of fresh water through technologies such as alkaline electrolyser, PEM (proton exchange membrane), and SOEC (solid oxide electrolyser). The production of green hydrogen from water is an energy intensive process, due to the high thermodynamic stability of water molecules. The cost of producing green hydrogen at scale is large proportional to the cost of renewable electricity. This requires green hydrogen production basins to be located close to regions/ geographies with access to surplus and low-cost renewable electricity, such as Australia, Middle East, Norway, Scotland and Chile. The current cost of green hydrogen in the UK has a 5-10 times cost premium as compared to fossil fuels. The primary inputs from green hydrogen production through electrolysis technologies are renewable electricity and freshwater. There has been an increasing concern globally on the availability and preservation of water resources. There are publications from water companies in the UK citing that the supply of constant fresh water supply for industrial applications such as green hydrogen production cannot be guaranteed under rapidly changing scenarios of climate change. There is a potential to set up large scale desalination plants to meet the fresh water for hydrogen production, however the large quantities of discharge water with high brine concentration might pose environmental hazards to marine habitat. This calls for alternate technologies to be developed which addresses the freshwater dependence for green hydrogen production and the significant green premium on cost structure. The paper describes a novel biocatalysis approach for production of green Hydrogen from wastewater, without requiring electricity input.

Many countries have announced hydrogen promotion strategies to achieve net zero CO2 emissions around 2050. The cost of producing low-carbon (green and blue) hydrogen has been projected to fall considerably as production is scaled up, although more so for green hydrogen than for blue hydrogen. This article uses a global computable general equilibrium (CGE) model to explore whether the cost reduction of green and blue hydrogen production can mitigate the use of fossil fuels and related carbon emissions. The results show that cost reduction can raise low-carbon hydrogen consumption markedly in relative terms but marginally in absolute terms, resulting in a modest decrease in fossil fuel use and related carbon emissions. The cost reduction of low-carbon hydrogen slightly lowers the use of coal and gas but marginally increases the use of oil. If regional CO2 taxes are introduced the increase in green hydrogen production is considerably larger than in the case of low-carbon hydrogen cost reduction alone. However, if cost reduction in low-carbon hydrogen is introduced in addition to the CO2 tax the emissions from fossil fuels are only marginally reduced. Hence, synergy effects between the two measures on emissions are practically absent. A low-carbon hydrogen cost reduction alone is effective but insufficient to have a substantial climate impact. This study also calls for modeling development to capture special user preferences for low-carbon hydrogen related to climate mitigation when phasing in new energy carriers like hydrogen.

By offering promising solutions to two critical issues – the integration of renewable energies into energy systems and the decarbonization of existing hydrogen applications – green hydrogen production through water electrolysis is set to play a crucial role in addressing the major challenges of the energy transition. However, the successful integration of renewable energy sources relies on gaining accurate insights into the impacts that intermittent electrical supply conditions induce on electrolyzers. Despite the rising importance of addressing intermittency issues to accelerate the widespread adoption of renewable energy sources, the state-of-the-art lacks research providing an in-depth understanding of these concerns. This paper endeavors to offer a comprehensive review of existing research, focusing on proton exchange membrane (PEM) and alkaline electrolysis technologies operating under intermittent operation. Despite growing interest over the last ten years, the review underscores the scarcity of industrial-scale databases for quantifying these impacts.

Green hydrogen production from industrial effluent electrolysis: A brief bibliometric analysis and literature review

The year 2018 saw the emergence of a broad social movement demanding stringent policies for climate change mitigation in Europe and other world regions. Widespread meteorological extreme events consistent with rapid global warming are stoking this movement. Especially in Europe, it has already changed the political landscape in a number of countries as green parties have scored record votes. Therefore, policymakers in many countries are sharpening their emission reduction targets for 2030 and 2050. At the same time, strong interest in an integrated hydrogen economy is emerging, where hydrogen would become a key fuel for transportation, industrial uses and even electricity generation. Countries as diverse as Australia, China, European Union (EU) member states and Japan are embarking on far-reaching strategies for a hydrogen economy, starting with the support of fuel- cell electric vehicles (FCEVs) but reaching beyond the transport sector. Hydrogen production technologies are manifold: feedstocks include fossil fuels and renewable electricity. At present, the costs of ‘green’ hydrogen, which is produced with renewable electricity, are still about five times higher than those of gas or coal-based hydrogen. An expansion of green hydrogen production, however, is likely to close the gap within less than a decade. Especially promising are emerging technologies that allow to use hydrogen as a fuel in existing thermal power plants without major refurbishment. The Gulf region faces a significant risk of oil exports becoming squeezed by a successful hydrogen revolution in the next decades. At the same time, Gulf countries are blessed with abundant solar energy resources that can easily be used for green and low-cost hydrogen production at large scale. Therefore, it is recommended that they proactively participate in this revolution, also given the region’s long experience with pipeline and ship transport of other flammable materials. Early movers are likely to benefit from scale effects and become leaders in the market, especially if there are lock-in effects for hydrogen supply chains – i.e. hydrogen importing countries wanting to continue to procure from suppliers with which they have long-term experience. The UAE is already a leader in the Middle East with the first solar hydrogen electrolysis plant under construction in Dubai and a fledgling FCEV fleet. Given its success in bringing down the cost of solar, the UAE would be in an excellent position to achieve the lowest global cost of green hydrogen production. With both the World Expo hosted by Dubai and the G20 presided by Saudi Arabia in 2020, the UAE could leverage either of these platforms to establish, and host, a high-profile International Hydrogen Economy Initiative (IHEI). This initiative could serve as a policy coordination tool between hydrogen importers and exporters, initially focusing on accelerating interactions between the Gulf region – a potential supplier – and Japan and the EU who both are likely to become key hydrogen importers in the next decade based on their self-defined energy policy targets.

Green hydrogen production via electrolysis from renewables is a promising method to achieve deep integration of renewable energy sources (RES) and boost decarbonisation of the whole energy system. Current studies mainly focus on low penetration levels, where both RES and electrolysers are treated as price-taker in the market. Here we develop an integrated hydrogen-electricity market simulation and investment tool, based on a mixed integer linear programming unit commitment with flexible hydrogen demand, with the aim of studying the techno-economic performance of a system with large-scale adoption of RES and electrolysis. We show how in a RES-dominated electricity market the marginal price could be set by the willingness-to-pay (WTP) price and installed capacity of electrolysers. The payback time or RES and electrolysers varies significantly for different resource portfolios and WTP prices of electrolysers. The results demonstrate how win-win RES and electrolyser economic equilibria can be achieved to produce large volumes of green hydrogen in low-carbon power systems.

Global annual CO2 emissions have increased more than 16 times in 2021 compared to 1990 and are expected to keep growing. Renewable energy is a critical way to reduce the impact on the climate. However, renewable energy production’s power output does not necessarily match the demand. The intermittent character of renewable electricity generation requires the storage of produced energy. Green hydrogen production via electrolysis is an opportunity to increase the integration of renewable energy sources and move hard-to-decarbonize sectors to climate neutrality. This research aims to assess the potential role of hydrogen in decarbonizing the energy sector in Latvia in the long term. Latvia’s energy system is modeled using the input/output deterministic energy system analysis model EnergyPlan. The model includes all the primary energy demand sectors, energy production, and storage, and allows the analysis of the impact of different strategies on the total costs and emissions of the system by 2050. The results show that the production potential of green hydrogen will increase significantly by 2030, taking into account the existing plans for the installation of 800 MW of wind and solar generating capacity on a national scale. The most significant potential is associated with using hydrogen in the transport sector in vehicles and in producing alternative fuels. Other uses include the decarbonization of the natural gas sector. In these scenarios, it is possible to reduce CO2 emissions while annual system costs increase.

Wind resource assessment and techno-economic analysis of wind energy and green hydrogen production in the Republic of Djibouti

Hydrogen has emerged as a key green energy carrier for deep decarbonisation, offering a viable pathway to reduce emissions from carbon-intensive industries while enabling greater integration of renewable energy source into the global energy system. This study provides a comprehensive review of green hydrogen production technologies, storage methods, and industrial applications, alongside the financial and regulatory landscape shaping its large-scale deployment. From techno-economic viewpoints, alkaline electrolysis offers cost advantages at approximately USD 270/kW compared with proton membrane exchange and solid oxide electrolysis. Storage technologies show levelised costs of USD 2.48–15.61/kg H 2 with scalability to gigawatt level, surpassing battery systems. Hydrogen adoption enables substantial decarbonisation in hard-to-abate sectors, with deployments estimated to cut more than 1 Mtonne CO 2 emissions annually in steelmaking and more than 100 ktonne in cement production. This study underscores the importance of international cooperation, outlining pathways for countries with abundant renewable resources (e.g., Canada, Australia) to emerge as major hydrogen producers, while nations with strong demand (e.g., Japan, South Korea) act as market catalysts. Finally, investment dynamics, government incentives, regulatory frameworks, and targeted policy recommendations are reviewed to provide a holistic perspective for building a resilient and sustainable hydrogen ecosystem. • Evaluates scalable green hydrogen production and storage technologies for large-scale deployment. • Examines economic viability, regulatory, and investment dynamics in hydrogen adoption. • Highlights hydrogen's role in decarbonising steel and cement industries. • Examines policy and regulation frameworks for green hydrogen advancement. • Analyses global supply chains via strategic corporation for resilient hydrogen economy.

Green hydrogen production by water splitting using scrap metals at high temperature

Hydrogen is a potential energy vector and storage medium for achieving net-zero emissions on a large scale.Among the various methods of producing low-carbon hydrogen, water electrolysis is the most appropriate and promising.Despite the commercial implementation of technical and industrial hydrogen production via electrolysis, conducting a comprehensive economic analysis of its production using grid or micro grid renewable energy systems presents challenges.Accordingly, it's important to review the approaches in the literature on the performance and costs of water electrolysis systems.This critical review aims to identify key performance parameters of the main commercial water electrolysers.In particular, the review will highlight advances in materials and challenges of Alkaline and Polymer Electrolyte Membrane commercial water electrolysis technologies.A techno-economic analysis using Multi-Criteria Decision Making (MCDM) will be performed on these technologies.The review will present various MCDM analysis methods used for these analyses.Results obtained from these methods will be compared and discussed, including their technological issues and the cost of hydrogen prospects, will be shown.Additionally, the potential of using Multi-Criteria Decision Making (MCDM) as a tool for supporting appropriate decision-making in hydrogen production and identifying research and development gaps in water electrolysis will be presented.Also, the limitations and performance of commercial electrolysers while suggesting possible solutions for achieving cost-effective hydrogen production will be described.The goal of this critical review is to propose innovative ideas and solutions for driving cost-effective green hydrogen production for commercial applications.The manuscript clearly states its objective to provide a comprehensive review of the fundamental principles and challenges associated with Proton Exchange Membrane (PEM) and Alkaline Water Electrolysis (AWE).It aims to identify current trends in water electrolysis technology and evaluate the techno-economic feasibility of hydrogen production using Multi-Criteria Decision Making (MCDM) tools.This objective is directly aligned with the need for practical solutions in green hydrogen production, emphasizing the study's contribution towards promoting the adoption of green hydrogen as a critical technology for a low-carbon economy.The introduction discusses the significant challenges in adopting electrolysis technologies, such as high capital costs and the need for innovation in materials and design.It mentions ongoing research to find affordable alternatives to expensive materials like platinum, aiming to reduce the overall cost of electrolysis.

Hydrogen energy, as a medium for long-term energy storage, needs to ensure the continuous and stable operation of the electrolyzer during the production of green hydrogen using wind energy. In this paper, based on the overall model of a wind power hydrogen production system, an integrated control strategy aimed at improving the quality of wind power generation, smoothing the hydrogen production process, and enhancing the stability of the system is proposed. The strategy combines key measures, such as the maximum power point tracking control of the wind turbine and the adaptive coordinated control of the electrochemical energy storage system, which can not only efficiently utilize the wind resources but also effectively ensure the stability of the bus voltage and the smoothness of the hydrogen production process. The simulation results show that the electrolyzer can operate at full power to produce hydrogen while the energy storage device is charging when wind energy is sufficient; the electrolyzer continuously produces hydrogen according to the wind energy when the wind speed is normal; and the energy storage device will take on the task of maintaining the operation of the electrolyzer when the wind speed is insufficient to ensure the stability and reliability of the system.

Green hydrogen production plants: A techno-economic review

This study explores the impact of the excessive utilization of fossil fuels on the environment. It highlights the potential of utilizing non-conventional energy sources, specifically geothermal and wind energy, to produce green hydrogen. The study includes various hydrogen production methods that integrate with these non-conventional energy resources and evaluates their feasibility as a sustainable alternative to fossil fuels. The processes involved in hydrogen production include the Kalina cycle, the Rankine cycle, and the utilization of Proton Exchange Membrane (PEM) electrolysis. The paper also addresses the challenges & opportunities associated with green hydrogen production, including environmental impacts, investment costs, infrastructure limitations and land availability. Additionally, it provides insights into the economic & environmental benefits of adopting renewable energy-integrated hydrogen production. It proposes solutions to overcome the identified challenges, ultimately promoting a carbon-free future.