Hydrogen by nature is a green fuel and produces little to no toxic emissions if used effectively (Wang et al., 2023; Anwar et al., 2021). Hydrogen is projected to be the clean energy of the future and it is expected that green hydrogen will be a decarbonization substitute for much of the fossil fuel energy used today, hence reducing the impacts posed by non-green fuels (Al-Zareer et al., 2018; Lee et al., 2018; Anwar et al., 2021; Nasser and Hassan, 2023).

Hydrogen as a fuel is fundamentally green; however, it is the means of its production that classifies it as green, grey, blue, red/pink, cyan/turquoise, brown and black, green, yellow, and white (Lubbe et al., 2023; Chaudhary et al., 2024). A fully green production process is preferable given the increasing requirements to reduce environmental impacts and decarbonization (Chi and Yu, 2018; Lubbe et al., 2023).

This study will share some of the different non-green and green hydrogen production technologies and color codes. Algeria currently produces grey hydrogen and is investigating ways to change to green hydrogen to tap into the European market. Algeria now is considering strategies to move into this space to reduce environmental impacts.

Here we will discuss the global demand trends for hydrogen, the types of hydrogen, and their production sources. The focus will be on green hydrogen, various technologies used to produce it, its drawbacks, the various cost contributors, and future research focuses.

Most hydrogen currently produced comes from the natural gas or coal industry, as well as steam reforming of natural gas; in general, these are not fully green (Wang et al., 2023). There is, however, a drive to boost green hydrogen production despite its challenges.

The different color coding categorization of produced hydrogen is generally based on the energy source, carbon emission associated with the production process, the overall environmental impacts, and the specific production process (Arcos and Santos, 2023).

Membrane science and technology have and will have a significant role to play in renewable and non-renewable hydrogen production as far as electrolyzers, water treatment, and separation and purification are involved.

There is a general drive to increase green hydrogen adoption, partly due to lower environmental impacts and costs, while driving favorable policies over its non-green hydrogen counterparts (Ishaq et al., 2022).

The electrolyzers and renewable electricity costs (Badgett et al., 2022) are among the factors which may be hindering green hydrogen growth and adoption. Hence, as costs reduce, green hydrogen will be able to compete with the dominant fossil fuel hydrogen.

The total cost of ownership (TCO) of green hydrogen mostly includes the costs of electrolyzers, ancillary equipment, installation, and operational costs. Ancillary equipment to electrolyzers includes cooling equipment, compression, electricity sources, water treatment, purification, dryers, and power electronics (IRENA, 2020).

There are costs associated with installing a complete system, while operating costs involve consumable and unit costs involved in the production process, including the electricity consumption rate and cost, water quality and consumption rate, and stack degradation and replacement rates. Other factors affecting overall production costs include operational efficiency, economy of scale, increasing automation, and design complexities. A large capacity system operating close to maximum capacity for longer hours is preferred for reducing costs and improving return on investment from an operational efficiency standpoint. Improving electrolyzers and their electrical efficiency are expected to reduce electrical consumption and costs. Generally, increasing module and manufacturing plant sizes can all significantly reduce costs in addition to automation (Corbeau and Merz, 2023). Each of the above factors could impact the overall cost differently, given that all the electrolyzers have some distinct differences.

From 2019 to 2022, electrical efficiencies generally improved for each type of electrolyzer. Electrolyzers improved in the following order: SOE > PEM > ALK > AEM. In 2050, system electrical efficiencies expressed in kilowatt-hours per kilogram of green hydrogen produced are expected to be lowest for SOE (<40) and similarly for ALK, PEM and AEM (<45) (IRENA, 2020; Patonia and Poudineh, 2022).

Generally, ALK requiring the use of low-cost steel or nickel alloy-plated material has the lowest cost (Miller et al., 2020). However, costs are associated with controlling the hydroxide electrolyte solution concentration, temperature, corrosion (Lohmann-Richters et al., 2021), and hydrogen produced needing further purification to meet some requirements.

PEM requires the use of expensive platinum-group metals, mostly iridium, to withstand the corrosive acid operating environment. The high voltage applied for high hydrogen production rates results in higher initial costs (Corbeau and Merz, 2023). This restricts opportunities for cost reduction.

SOE, still in development, has the flexibility of being constructed from a variety of materials including steel, nickel, and zirconia (Hauch et al., 2020). This offers some advantages in reducing costs. However, in the current developmental stages, manufacturing process complexities mean that it is more expensive than ALK and PEM. The expectation is that SOE still will implement cost reduction opportunities (Minary-Jolandan, 2022).

AEM is a better alternative to ALK for easy renewable energy compatibility, costs the same as ALK, and performs like PEM. Moreover, AEM is being explored as an alternative to PEM but with lower overall costs. AEM performance with PEM iridium anodes has returned the best AEM results (Miller, 2022; Yang, et al., 2023).

In conclusion, selection of any of these electrolyzers depends on the specific application, availability of resources and infrastructure, and expected project viability (Hydrogen Newsletter, 2022).

While green hydrogen production using an electrolyzer is driven by many factors, available electricity and costs are among the most critical. Industry guides suggest that economic viability could favor higher efficiency and higher capex electrolyzers such as SOE, which may be applicable to areas with a scarcity of renewable electricity, while lower efficiency and lower capex electrolyzers such as ALK may be suitable for areas with sufficient renewable electricity. Driving green hydrogen production costs down depends on the upfront investment, electricity availability and cost, efficiency, stack degradation, and replacement rates. Other considerations include the effects of module size, manufacturing economy of scale, hydrogen produced for specific applications, feed water quality, and the integration of an electrolyzer of interest with intermittent renewable energy operation (Corbeau and Merz, 2023).

Remarkably, some of these parameters may be coupled such that an improvement in any of the parameters could adversely impact the others. This requires making a conscious decision on selection. The ALK, AEM, PEM, and SOE electrolyzers operate differently, hence entailing different cost implications, effectiveness, and production system designs (Kumar and Lim, 2022).

Furthermore, the fast-paced industrial innovation occurs behind closed doors, so up-to-date information is lacking in the public domain. This lack of access to new information means that outdated information is available to academia and the public (Corbeau and Merz, 2023).

The role of membrane science and technology in green hydrogen production using electrolytic splitting of water cannot be overstated, from transporting ionic species from one electrode to the other in electrolyzers, treating the different water sources to meet electrolyzers’ feed water quality to ensure improved productivity and system lives, and producing hydrogen purification.

Increasing use of green hydrogen over established fuels will not only lead to decarbonization of the energy system but a revolution in the water industry, leading to improved water treatment technologies and water use strategies in the face of dwindling clean water resources. The water industry is and will play a vital role in electrolytic green hydrogen production given that water is one of the key raw materials. Hence, countries seeking to adopt net zero strategies should consider a more integrated approach to renewable electricity, water, and green hydrogen (Newborough and Cooley, 2021).

Future green hydrogen development includes increasing adoption of renewable hydrogen by lowering costs and instituting favorable policies to promote it over non-green hydrogen (Kumar and Lim, 2022).

SOE, still in development, is expected to emerge as the best electrolytic solution with lower costs and high efficiency (Miller, 2022). Other green hydrogen developments include exploring (1) photolytic means, where sunlight is directly used to split water into hydrogen and oxygen, (2) thermochemically converting biomass into liquid or gas and separating hydrogen, and (3) biological production of hydrogen by microbes (EIA, 2023).

Growing infrastructure demands include hydrogen refueling stations, storage, and transportation which are crucial for the industry’s success and growth. Economic opportunities associated with green hydrogen include the growth of new industries, job creation, and economic expansion (Hassan et al., 2024; Jones, 2024). The future of hydrogen as part of the global energy mix will depend on continued investment, improvement, lowering of costs, increasing adoption, and policy direction.

Algeria is a motivated player in the hydrogen industry given that is has many assets for becoming a regional and international player. Currently, Algeria is involved in the blue hydrogen industry. However, it wants to join the fight against climate change and plans to become a leading green hydrogen production country. The road map towards this includes (1) regulatory and institutional adaptation, (2) human capital development, (3) industrial integration and growth, (4) financing mechanisms and incentives, (5) international cooperation and technology transfer, and (6) deployment of the hydrogen sector. The road map involves the following actionable phases with objectives and timelines. (1) Start-up phase (2023–2030) focusing on start-up activities and training, laying the groundwork for building projects and expertise, and initiating pilot projects to explore hydrogen production and utilization. (2) Market expansion and creation phase (2030–2040) that emphasizes the shift to market expansion and creation, scale-up, and the establishment of markets for the applications. (3) Industrialization and export phase (2040–2050) that prioritizes the export of hydrogen derivatives and contributing to global energy markets. (National Hydrogen Development Strategy in Algeria, 2023).

Algeria’s energy transition quest will promote energy transition, innovation, and efficiency (ITA, 2023). Moreover, Algeria seeks to establish a supportive hydrogen sector framework by 2050 dubbed the “The Algerian Strategy on Green Hydrogen 2050”. Algeria’s ambitious target includes reducing its greenhouse gases (GHG) and petroleum products consumption. Algeria projects to export 30–40 TWh of gaseous, liquefied, and derived green hydrogen by 2040 (Stambouli et al., 2024).

Algeria is taking the necessary steps in developing strategies and policies. It is forming internal and external alliances and dealing with some of the existing challenges to make it align with the needs of a green hydrogen economy. Algeria’s plans to appeal to the European market across the Mediterranean. It has acquired land and solved its water scarcity issues by building desalination plants as well as boosting green energy resources with solar and wind energy systems. Moreover, Algeria is considering ways to reduce the impacts of its blue hydrogen industry amid its pursuit of green hydrogen production. Furthermore, it is collaborating with local energy clusters to build and sustain the overall energy ecosystem (National Hydrogen Development Strategy in Algeria, 2023).

Algeria’s Sonatrach state-owned oil company signed a memorandum of understanding (MoU) with Hecate Energy Global Renewables (HGR Energy) to explore both renewable energy and green hydrogen projects in Algeria (Djunisic, 2024).

One of Algeria’s local energy clusters is the Green Energy Cluster Algeria (GEC) which is a collaborative organization including industries, universities, research centers and institutes, and representatives from key government ministries. Its main goal is to foster synergies among its members, promote competitiveness, contribute to sector-specific training to add to its human resource capacity to develop and transfer the knowledge base to support Algeria’s hydrogen economy (Green Energy Cluster Algeria, 2024).

Algeria is on track with the start-up phase of its roadmap, building more capability as it positions itself, including lowering costs and moving in the right direction to grow its green hydrogen base. Currently, it is addressing challenges to its water supply by installing desalination plants, designating land, building more solar energy plants, collaborating with local energy clusters, signing MoUs with major global companies for hydrogen projects, and pilot projects to build expertise and training (National Hydrogen Development Strategy in Algeria, 2023).

The above review presents some information on renewable hydrogen production strategies and Algeria’s plans so that other developing nations can decide whether to replace existing non-renewable hydrogen production with renewable hydrogen.