The Potential Role of Africa in Green Hydrogen Production: A Short-Term Roadmap to Protect the World’s Future from Climate Crisis

Abstract

The global need for energy has risen sharply recently. A global shift to clean energy is urgently needed to avoid catastrophic climate impacts. Hydrogen (H₂) has emerged as a potential alternative energy source with near-net-zero emissions. In the African continent, for sustainable access to clean energy and the transition away from fossil fuels, this paper presents a new approach through which waste energy can produce green hydrogen from biomass. Bio-based hydrogen employing organic waste and biomass is recommended using biological (anaerobic digestion and fermentation) processes for scalable, cheaper, and low-carbon hydrogen. By reviewing all methods for producing green hydrogen, dark fermentation can be applied in developed and developing countries without putting pressure on natural resources such as freshwater and rare metals, the primary feedstocks used in producing green hydrogen by electrolysis. It can be expanded to produce medium- and long-term green hydrogen without relying heavily on energy sources or building expensive infrastructure. Implementing the dark fermentation process can support poor communities in producing green hydrogen as an energy source regardless of political and tribal conflicts, unlike other methods that require political stability. In addition, this approach does not require the approval of new legislation. Such processes can ensure the minimization of waste and greenhouse gases. To achieve cost reduction in hydrogen production by 2030, governments should develop a strategy to expand the use of dark fermentation reactors and utilize hot water from various industrial processes (waste energy recovery from hot wastewater).

1. Introduction

Worldwide, as countries’ populations and economies grow, energy demand is expected to increase significantly by 2050, and the need for energy will increase by approximately 80% [1]. This reveals the existing global concern about the emissions of greenhouse gases (GHGs), for example, carbon dioxide (CO₂) and methane (CH₄), which lead the world into a disturbing climate change crisis. Non-renewable sources, such as fossil fuel, natural gas, and coal, represent most current energy sources, emitting over 33 gigatons (Gt) of CO₂-eq/a. Hence, the United Nations (UN) documented the 7th Sustainable Development Goals (SDGs 7) towards confirming access to reasonable, dependable, sustainable, and recent energy [2]. In addition, after the 21st Conference of the Parts in Paris, energy decarbonizing has become an essential goal for each government. Therefore, countries have begun developing national approaches and policies to ensure energy grid transitions [3]. Regarding energy security issues, major influential countries are actively shifting toward sustainable energy sources [4].

African nation policymakers are facing the challenge of enabling economic growth while managing the related dramatic increases in energy demand [5]. Africa’s population is approximately 16% of the world’s residents and is the second-most populous continent worldwide, with almost 1.34 billion people, growing with an annual percentage of 2.5% [6]. Despite the total primary energy supply (TPES) visibly increasing by 3% annually, in the African continent, the energy consumption rate is the lowest per capita worldwide; it consumes no more than 3.3% of global primary energy. Over 640 million Africans have no access to electricity, affecting approximately 50% of West Africans, 60% of South Africans, 2% of North Africans, and the majority of Eastern and middle Africans. Meanwhile, the Gross Domestic Product (GDP) per capita has reached a peak in North Africa. This makes the electricity access rate on the continent the lowest in the world at just over 40% [7].

Africa holds 7.6% and 7.5% of the world’s confirmed crude oil and natural gas reserves, representing 9.1% and 6% of total global production, respectively. Moreover, about 4.2% and 3.9% of global consumption is from oil and natural gas. South Africa is the seventh major coal producer worldwide [8]. Africa’s electricity generation comes from 40% natural gas, 30% coal, 16% hydropower, and 9% oil, with vast provincial differences; for example, South Africa, the 14th highest GHG emitter worldwide, depends primarily on coal, whereas North Africa depends on natural gas [9,10].

Energy in Africa is based on a mix of renewables and fossil fuels, which will be a bridge during the roadmap transition to green energy. This transition aids in controlling economic vulnerability and facing the extraordinary prices of imported fuels, especially during global disputes and wars. Fossil fuel is Africa’s primary energy source, prompting many African governments to provide subsidies for fossil fuel products [11]. Due to efficient combustion kinetics, lack of CO₂ emissions, and high energy, hydrogen (H₂) is specified as a promising alternative fuel. However, consuming hydrogen to decarbonize the economy necessitates producing it through a non-emission-producing technique. Producing green hydrogen using this method is an essential approach that integrates the requirements of sustainable development in the long term [12]. Figure 1 illustrates the potential hydrogen production worldwide.

This work will focus on Africa’s most mature green methods for short-term hydrogen production.

2. Africa’s Natural Resources and Possible Energy Mix

Africa has vast renewable energy (RE) resources that support the continent’s demand for electricity to enhance economic progress and achieve broader goals for CO₂ reduction. Africa has the world’s highest untapped renewable energy potential, only utilizing about 11% of its capacity [14,15]. Whereas hydroelectric potential is up to 350 gigawatts (GW), solar energy has a potential of about 10 terawatts (TW) (with an annual solar radiation of about 2000 kW h/m²), geothermal energy is estimated at 15 GW, and wind energy at 110 GW [16]. In addition to a significant bioenergy potential estimated at 520 GWh yearly, wood is supplied from abundant forests. Despite these rich resources, Africa still faces many energy-related challenges.

To support its global decarbonization market structure, green hydrogen will require technology scaling, infrastructure deployment, cost reduction, and the enactment of appropriate legislation and policies. Africa is rich in RE sources, with a wealth in wind, solar, and other natural resources. However, its abundant RE sources are not well exploited, and the African energy mix relies mainly on hydropower, which accounts for 15%, compared to 5% of other RE sources in electricity generation [17].

The total energy supply (TES) in Africa increased by 83% from 2000 to 2022, reaching about 33 337 003 TJ (terajoule), accounting for 5% of the global total in 2022. The largest sources of energy in Africa in 2022 were biofuels and waste, with a total energy supply of 39%, and oil, with a total energy supply of 26% [18], as illustrated in Figure 2.

Hydrogen has been widely explored as a potential global energy resource in recent years because of its favorable benefits as a perfect energy carrier, which include its cleaner emission, higher energy density, and capability to be transported and stored [19,20]. According to the production technology applied (Figure 3), hydrogen is identified by thirteen color codes. These codes include orange (gold), green, blue, gray, yellow, brown, black, turquoise, purple, cyan, pink, red, and white hydrogen [21,22,23]. The two primary colors associated with hydrogen are green and blue [15]. Green hydrogen technologies are utilized to mitigate anthropogenic GHG emissions. However, the global share of green hydrogen in total hydrogen production remains below 17%. Worldwide strategies for supporting green hydrogen production pathways are emerging, aiming to increase output tenfold or more by 2050 [5]. This is driven by the urgent need for H₂-based fuels to substitute fossil fuels to combat climate change. Generally, H₂ is particularly desirable in countries with extreme import dependency.

3. Africa as a Potential Hub for Green Hydrogen Production (GHP)

Ambitious green H₂ (renewable H₂) production goals have been established to mitigate climate change. From a GHG mitigation viewpoint, green H₂ is the best approach. The International Renewable Energy Agency (IRENA) states that H₂ demand must grow to 614 Mt/a to reach a net-zero carbon emissions target [25]. Only 30% of electricity generation is currently powered by renewable low-carbon technologies [26]. An estimated 95% originates from non-renewable energy sources (fossil fuel-based H₂) [27]. International goals for renewable energy adoption aim to overcome the climate change crisis and move the globe toward net-zero emissions and carbon-neutral energy sectors by 2050. Moreover, the strain on resources, particularly water and RE, leads to competition with other critical uses. Despite the promising potential of green H₂, the path to large-scale production is burdened with barriers and challenges, which demands a holistic and strategic approach. Worldwide H₂ production stands at over 50 million tons per annum. To achieve zero-carbon (carbon-neutral) H₂ as part of a clean global energy system, a cost-effective process must be provided in the short-term, and long-term global effort is needed to shift from high operational expenditure (OPEX) and overcome barriers of energy-intensive and expensive processes [28].

Expanding production capacity and cost reduction will have a notable benefit for the global economy. It boosts economic growth and plays a part in providing additional employment to susceptible societies and entities. Between 300 and 700 jobs can be created for each 1 GWe of installed Power-to-X capacity [29]. The European Union Energy Earth Shots initiative, designed to fast-track inexpensive, clean energy solutions, has established its initial target or “Shot” to decrease the price of zero-emission hydrogen to USD 1 per 1 kg within a decade. In the United States, the Department of Energy (DOE) has set a goal to decrease hydrogen production costs to USD 1 per kilogram by 2030. Strengthening the economy of clean hydrogen would reduce exposure to geopolitical and oil price variability, as well as lower energy costs for nations that rely on fossil fuels [23].

Cost-cutting measures are critical to support the vision of a future powered by hydrogen fuel, and incentives in research and development (R&D) are required [30]. Economically, scaling hydrogen-based energy from pilot-scale projects to large-scale production capacities is not easy; the high capital requirements can be discouraging. R&D should work on expanding the horizons of green hydrogen production technologies to combat climate change and make the cost feasible in the short term. International collaboration is crucial for realizing the global hydrogen economy, as it allows for the sharing of knowledge and resources globally, leveraging the varied strengths of all countries [31]. Hence, creating policy frameworks and collaborating with governments, industry stakeholders, and researchers are required.

Africa is a key player in green hydrogen production; besides the local initiatives, various global initiatives have been launched for trading the continent’s green H₂ [8]. The accessibility of renewable energy sources (RESs) characterizes Africa’s elevated opportunity to produce green hydrogen-based energy. African Hydrogen Partnership (AHP) was established to initiate renewable hydrogen economies, foster joint efforts, and build partnerships across borders. This will aid in offering solutions to African countries’ economic, social, and environmental barriers. Despite so, the “hydrogen futures” notion took root among scholars and the political field in the 2000s [32]. But the current unprecedented gas crisis, coupled with continuing market instability and political unpredictability due to the diplomatic and physical Russia–Ukraine conflict, has accelerated a pioneering “dash for hydrogen gas” in Europe to mitigate energy security risks [33]. European nations face several challenges in attaining the local capacity to generate their renewable energy regionally [34]. Consequently, European organizations identify African countries as potential partners, seeking their support in achieving the goal of the Paris Agreement for a green future. This collaboration between these two continents is part of the “European Hydrogen Strategy”. A business umbrella organization called “Hydrogen Europe” has revealed that the existing African natural gas infrastructure can directly transport renewable hydrogen from North Africa to Europe. Green H₂ transportation in Africa will benefit from using pipelines that will reduce the price to about 0.22 USD/kg, in the direction of transference from North Africa toward Europe [35]. Regarding the existing infrastructure routes of seaports, roads, and railways, AHP mapped six possible landing regions, specifically Morocco, Egypt, South Africa, Ethiopia–Djibouti, Nigeria–Ghana, and Tanzania–Rwanda–Kenya for a green H₂ economy [36], as illustrated in Figure 4a,b. Not all countries have access to renewable sources, which might limit their dependence on these renewable sources [37]. North African regions’ high renewable energy potential means a high potential for green H₂ production. The joint strategy between North Africa and Europe on renewable H₂ can support the progress of the European energy arrangement established on a cutting-edge hydrogen policy of 50% renewable hydrogen and 50% renewable electricity by 2050 [38]. The hydrogen strategy identifies potential projects with stakeholders and consultants across African and European nations, strategically subsidized by the European Fund for Sustainable Development. Additionally, in 2020, the European Investment Bank (EIB) provided over EUR 3 billion across Africa to achieve (1) the expansion of 2050 decarbonization targets; (2) climate-related financing, estimated at 2250 TWh or 24% of the total energy demand; and (3) solutions addressing challenges related to poverty, peace, fairness, ecological dilapidation, and discrimination [39].

Additionally, further funds, such as the Connecting Europe Facility (CEF), were allocated to support the advancement of critical infrastructure investments [6]. The new Neighborhood Development and International Cooperation Instrument (NDICI) was launched with a total fund of EUR 80 billion to focus on climate objectives from 2021 to 2027 [40]. Projects of Common Interest (PCIs) were established via the regulation of the Trans European Energy Networks (TEN-E Regulation) and European Energy Networks, focusing on hydrogen.

Figure 4. (a) Six recognized potential landing regions [10], (b) capabilities of the selected landing zones for hydrogen market development [41].

Figure 4. (a) Six recognized potential landing regions [10], (b) capabilities of the selected landing zones for hydrogen market development [41].

4. Possible Water Usage Consequences for GHP in Africa

Freshwater is a key input resource for green hydrogen production within an electrolyzer powered by renewable electricity. In the electrolysis process, GH is produced by splitting (breaking apart) freshwater (H₂O) into hydrogen (H₂) and oxygen (O₂) gases (Equation (1)). To yield 1 kg of hydrogen by electrolysis, the solid oxide electrolyzer cells (SOECs) currently consume 9.1 kg of freshwater [42,43], and polymer electrolyte membrane (PEM) electrolyzers consume from 18 to 25 kg [44,45]. In addition, 3.7 to 5.2 tons of freshwater is used for each kilowatt peak (KWp) in the upstream sections of photovoltaic (PV) module construction, in addition to PV mirror cooling and cleaning during operation [46]. In addition to using freshwater resources in constructing and maintaining solar and wind energy plants, this can be problematic in water-scarce areas.

2 H₂O (l) → 2 H₂ (g) + O₂ (g)

(1)

While Africa has abundant water resources, not every area has them, and several regions are currently freshwater-stressed [47,48]. In Africa, using scarce freshwater in electrolysis technology can impede social and economic growth, create water conflicts and disputes, impoverish communities, increase hunger and sickness, fuel violence, and exacerbate insecurity and conflict-driven migrations in fragile regions [47]. For example, around 400 million people in sub-Saharan Africa are unable to obtain clean water for drinking, and this situation is expected to worsen with global warming and climate change [47,49]. Conflicts between herders and farmers in the Horn of Africa, disputes over large dam projects in the Basin of Nile River, and turbulence in the Lake Chad district reveal the ways in which water-related conflicts are deeply intertwined with broader socio-economic threats, with far-reaching implications for development [50]. Figure 5 illustrates the ongoing decade-long trend of rising forced displacement in Africa, with the number of displaced individuals surpassing 40 million in 2023. Even the desalination of non-freshwater (wastewater and sea water bodies) for GHP requires high energy and produces a toxic hypersaline effluent [51,52,53].

Electrolysis-based H₂ production is strongly connected to power generation, which is enhanced with the rise in power production. Typically, RE sources are intermittent, and their availability depends on the time and weather, leading to inconsistency and variation in supply. Therefore, relying solely on a renewable resource is not straightforward [55]. Additionally, the accessibility of these resources is not uniform across areas owing to different geographic distributions. Some areas have wind, others have sunlight, and some do not have enough access to these sources. For commercial viability, solar energy requires a solar irradiance of about 3.5 kWh/m²/day, and wind power requires a wind speed of about 5 m/s for economical operation [56]. Integration between renewable resources (applying hybrid systems) should be carried out to mitigate intermittency and availability issues. To address the discrepancy between production and load, multiple energy conversions through a combined cycle power plant (CCPP) are necessary to meet the power demand of electrolyzers [57].

Regarding electrolysis techniques, elevated quantities of minerals, for instance, nickel, platinum, zirconium, lanthanum, iridium, palladium, and yttrium, are essential [58]. In addition, RE technology components, including wind turbines, PV glass and cells, and generators, require large amounts of complex metals and minerals for extraction, purification, and manufacturing, such as steel, aluminum, copper, silver, gallium, silicon, cadmium, neodymium (or dysprosium), tellurium, and indium [59]. Several countries worldwide have excluded H₂ production by electrolyzers, as these pieces of equipment rely heavily on noble minerals that may not be readily available and increase capital expenditures [60]. The prohibitive cost of the electrolyzer technique faces limited supporting infrastructure and financing; many investments and ventures are needed. Establishing the required infrastructure is quite a considerable investment, and in a developing continent such as Africa, this may act as a hindrance since many countries on the continent are battling colossal debt. Figure 6 shows public debt across African countries in 2022 in USD billions.

Water scarcity and conflicts in Africa are complex issues needing multifaceted solutions, including enhanced water resource management, sustainable practice investments, regional cooperation, and conflict resolution mechanisms. Konecna [62] identified 44 water conflicts in Africa from 2018 to 2023, most likely related to several factors, which are agricultural dependency, water infrastructure investments, ethnic segregation, income inequality, political instability, water scarcity, water quality, and population growth alongside urbanization rates. Some case studies include the Nile River Basin (Egypt, Sudan, and Ethiopia), where Ethiopia seeks to produce hydroelectric power by constructing the Grand Ethiopian Renaissance Dam (GERD), which has led to tensions between these countries; the Lake Chad Basin (Nigeria, Chad, Niger, and Cameroon), where, as a result of climate change, intensive use, and unsustainable agricultural activities, Lake Chad has shrunk drastically by about 90%, which severely affects the livelihoods of millions of residents who rely on the lake for farming and fishing; the Zambezi River Basin (Zambia and Zimbabwe), where variations in water distribution have been a basis of disagreement due to water management and dam construction (the Kariba Dam, which supplies hydroelectric power to both countries); the Senegal River Basin (Senegal and Mauritania), where disputes have arisen regarding the distribution of water resources for agricultural and industrial activities, in addition to the construction of the Manantali Dam, which exacerbated these conflicts; and the Rift Valley Lakes, which include Lakes Nakuru, Naivasha, and Bogoria (Kenya, Ethiopia, and Tanzania), where conflicts have arisen because of significant water stress due to increasing demand from agriculture, tourism, and urbanization.

5. Land Use Dimension vs. GHP via Electrolysis in Africa

Generally, African countries have extensive vacant lands, and gaining access to these lands for large-scale development faces significant difficulty in most countries. Meanwhile, RE for GHP via electrolysis facilities requires large areas of land to develop the electrolysis infrastructure [63], and establishing wind and solar energy infrastructure requires powering the electrolyzers [64]. Africa is home to many developing countries with land used for housing, agriculture, and bio-diversification [65]. The construction of large RE and GHP infrastructure plants may lead to deforestation, soil contamination, erosion, and ecological imbalances [66]. In Africa, land acquisition is complicated due to tenure regimes [67]. Similarly, the acquisition and degradation of productive lands for GHP might exacerbate existing food shortages and insecurity, particularly in countries suffering from scarce food production and accessibility [68]. Natural habitats and biodiversity can be negatively impacted, particularly in areas with elevated biodiversity [69]. GHP in Africa will put the land under further stress due to mining rare elements and raw materials for electrolysis technology. All these issues could further be exacerbated, leading to conflicts, forced migration, and human rights abuse [70].

For large-scale hydrogen production, land requirements can vary significantly depending on the technology applied and the energy source. The land requirements may vary based on the land needed for facilities, biomass cultivation, and renewable energy installations. As stated by Tonelli et al. [71], the land supply for each country, C, is calculated according to Equation (2):

A_c = D_c/(S_cη) ∀ c ∈ C

(2)

where D_c is the total demand of hydrogen in country c; A_c is the land area occupied; S_c is the amount of energy generated per unit of area; and η is the conversion efficiency (electricity to hydrogen).

Finally, electrolyzers for GHP put pressure on scarce water resources, rare elements, and land. The site of electrolyzer investment needs to be carefully selected, considering its richness in renewable energy sources, tenure security, political stabilities, and overall security [6].

6. Biomass as a Multi-Gain Green Gold in GHP

6.1. Historical Background and Conversion Routes from Biomass to Hydrogen

People have utilized biomass as an energy source for cooking and heating since about 1.5 million years ago. Burning has been the primary way of converting biomass into energy, and it is commonly applied in developing regions lacking bioenergy facilities. Modern energy production from biomass has become an essential renewable energy source, surpassing wind and solar energy as alternative energy sources [72]. Up until 1870, biomass was the principal energy source, and wood was the primary energy producer. In the late 1600s, Britain’s requirement for wood dramatically increased, and timber was scarce. Wood was replaced as the main energy source by coal and then petroleum [73]. Despite fossil fuels (coal and petroleum) originating from ancient biomass, they are not classified as biomass due to extensive geological alteration [74]. Therefore, biomass is the only carbon-based renewable resource in nature, containing other abundant elements, such as hydrogen and oxygen. The physicochemical properties of biomass are similar to those of fossil fuels, making it an ideal alternative for H₂ production [75]. According to the type and quantity of biomass feedstock, it can be converted into hydrogen-rich gas and other forms of energy products by using thermochemical, biochemical/biological, electrochemical, and hybrid conversion processes [74,76,77].

Generally, the chemical exergy exerted from biomass is difficult to quantify [78]. Consequently, a standardized environmental approach and the statistical correlation suggested by Szargut and Styrylskawas [79], as represented by Equations (3) and (4), may be used.

$$e_{0,\mathrm{b}\mathrm{i}\mathrm{o}\mathrm{m}\mathrm{a}\mathrm{s}\mathrm{s}}={\beta \mathrm{L}\mathrm{H}\mathrm{V}}_{\mathrm{b}\mathrm{i}\mathrm{o}\mathrm{m}\mathrm{a}\mathrm{s}\mathrm{s}}$$

(3)

where e_0,biomass is the standard chemical exergy of a pure chemical compound (biomass at the environmental temperature T0 and environmental pressure P0), LHV_biomass is the lower heating value, and β is defined as

$$\beta ={\displaystyle \frac{1.0412+0.2160\left(\frac{{\mathrm{Z}}_{\mathrm{H}}}{{\mathrm{Z}}_{\mathrm{C}}}\right)-0.2499\left(\frac{{\mathrm{Z}}_{\mathrm{O}}}{{\mathrm{Z}}_{\mathrm{C}}}\right)\left[1+0.7884\left(\frac{{\mathrm{Z}}_{\mathrm{H}}}{{\mathrm{Z}}_{\mathrm{C}}}\right)\right]+0.0450\left(\frac{{\mathrm{Z}}_{\mathrm{N}}}{{\mathrm{Z}}_{\mathrm{C}}}\right) }{1-0.3035\left(\frac{{\mathrm{Z}}_{\mathrm{O}}}{{\mathrm{Z}}_{\mathrm{C}}}\right)}}$$

(4)

where Z_H, Z_C, Z_O, and Z_N are the weight fractions of hydrogen, carbon, oxygen, and nitrogen in the biomass, respectively.

Largely, according to Roos [80], for renewable H₂ generation costs, Equation (5) is applied to detect the levelized cost of H₂ (LCOH):

$${\mathrm{L}\mathrm{C}\mathrm{O}\mathrm{H}}_2\left[{\displaystyle \frac{\mathrm{€}}{{\mathrm{k}\mathrm{g}}_{{\mathrm{H}}_2}}}\right]={\left({\mathrm{O}\mathrm{P}\mathrm{E}\mathrm{X}}_{el}+{\mathrm{O}\mathrm{P}\mathrm{E}\mathrm{X}}_{{\mathrm{H}}_2\mathrm{O}}\right)}_{\mathrm{v}\mathrm{a}\mathrm{r}}\left[{\displaystyle \frac{\mathrm{€}}{{\mathrm{k}\mathrm{g}}_{{\mathrm{H}}_2}}}\right]+{\displaystyle \frac{\left({\mathrm{C}\mathrm{A}\mathrm{P}\mathrm{E}\mathrm{X}}_{{\mathrm{H}}_2}\left[\frac{\mathrm{€}}{{\mathrm{k}\mathrm{W}}_{el}}\right]\times {crf}_{{\mathrm{H}}_2}\left[\frac{1}{\mathrm{y}}\right]+{\mathrm{O}\mathrm{P}\mathrm{E}\mathrm{X}}_{{\mathrm{H}}_{2}fixed}\left[\frac{\mathrm{€}}{{\mathrm{k}\mathrm{W}}_{el} \mathrm{x} y}\right]\right)\times {\mathrm{L}\mathrm{H}\mathrm{V}}_{{\mathrm{H}}_2}\left[\frac{{\mathrm{k}\mathrm{W}h}_{output}}{{\mathrm{k}\mathrm{g}}_{{\mathrm{H}}_2}}\right]}{{FLH}_{{\mathrm{H}}_2}\left[\frac{h}{\mathrm{y}}\right]\times {\mathsf{\eta }}_{{elect.\mathrm{t}\mathrm{o} \mathrm{H}}_2}\left[\frac{{\mathrm{k}\mathrm{W}h}_{{\mathrm{H}}_2}}{{\mathrm{k}\mathrm{W}h}_{\mathrm{e}\mathrm{l}} }\right]}}$$

(5)

where LCOH is the levelized cost of hydrogen, OPEX is the operational expenditure, CAPEX is the capital expenditure, crf is the capital recovery factor, FLH is the full load hours, ${\mathrm{L}\mathrm{H}\mathrm{V}}_{{\mathrm{H}}_2}$ is the lower heating value of hydrogen, and η is the conversion efficiency.

6.2. Near-Term Prospects of Biomass-Based GHP in Africa

Biomass is a renewable energy source resulting from various waste materials, including agro-industrial waste, sewage sludge, industrial by-products, animal waste, a diverse range of municipal wastes, and various other sources. Hydrogen production from biomass is crucial in emerging sustainable RE systems, potentially serving as a practical step in reducing waste and achieving a climate with zero GHG emissions [23]. Biological hydrogen production applying biomass as clean substitute energy is attractive and progressively crucial as it is renewable, generates low CO₂ emissions, has a low sulfur content, and minimizes waste. Green H₂ is produced from biomass (biomass-based H₂) technologies, ensures energy efficiency, and requires fewer resources [11]. As biomass-based H₂ technologies advance in terms of scalability and become more cost-effective, they are predicted to be essential in transitioning to a green energy future.

Africa has a small carbon footprint of around 3% of the world’s GHG emission. Traditional biomass is the primary source of energy for everyday demands. As mentioned, the growth in PV development by 2050, combined with intensive mining for raw materials required by renewable energy technologies, might raise serious concerns, as pasturelands, croplands, plantations, and urban regions have expanded in Africa over the past two decades and are expected to continue growing in the coming decades [81,82]. Hence, developing and improving the use of biomass offers an effective way to promote a circular H₂ economy by introducing cheaper, cleaner, and more sustainable energy sources into the continent’s energy mix. Therefore, residual biomass management systems will benefit from bio-H₂, since this type of H₂ does not compete with electricity for domestic consumption.

This could make it suitable for transition in the mid- and long-term in the direction of a H₂ economy. Biomass-based green H₂ production could meet the energy transition goal without putting the electricity demand of the African countries at risk. Therefore, fewer investments will be required in the short term with the growth in bio-H₂ capacity. Biological hydrogen plants, which utilize waste and biomass as feedstock, are characterized by reduced stress on the energy grid and reduced demand for renewables. This flexibility allows hydrogen to be used in rural areas where electricity poverty remains prevalent. Bouvet et al. [83] estimated above-ground biomass (AGB) at nearly 85 Mg·ha⁻¹. In addition, AGB values of up to 300 Mg·ha⁻¹ were assigned to dense forests and diverse vegetation (Figure 7a,b).

Thermochemical and biological technologies are the two pathways applied to convert biomass. Thermochemical processes include combustion, pyrolysis, gasification, and liquefaction. Combustion gas or gaseous streams and methane (CH₄) are obtained [85]. Meanwhile, biological processes frequently producing CH₄ include biophotolysis, photofermentation, and dark fermentation. According to the composition and properties of the biomass, the GHP pathway is selected [86].

Dark fermentation of biomass is a mature commercialized approach with good long-term prospects among hydrogen production technologies, demonstrating efficiencies of 60–80% [87]. It produces hydrogen from biomass by converting simple sugars into hydrogen, ethanol, carbon dioxide, or organic acids (mainly acetic, lactic, and butyric acid), as illustrated in Equations (6)–(9). This can be used in manufacturing processes that do not separate hydrogen from other gases, such as methanol or steel production. Additionally, bioethanol reforming can drive the H₂ industry due to its high H₂ yield. Dark fermentation procedures offer advantages and are particularly profitable as they can continuously yield hydrogen and do not depend on solar energy [88]. In addition, it can be powered by waste heat from industrial processes to make green hydrogen production more cost-effective and scalable [89]. Two-stage fermentation can be used to produce more hydrogen, starting with dark fermentation and proceeding to photofermentation. The benefit of this technique (for commercial use) is its low-cost relative to electrolyzers and acceptable process productivity.

Throughout several phases, dark fermentation reactions, facilitated by anaerobic microorganisms, produce hydrogen gas in the dark through a series of biochemical processes at temperatures ranging from 25 to 80 °C or higher. The primary phase involves the enzymatic hydrolysis of high-molecular-weight organics into water-soluble organics and the hydrolysis of simple organics into volatile fatty acids (VFAs), H₂, and CO₂ [90,91]. H₂ is mainly formed by the anaerobic metabolism of pyruvates obtained through carbohydrate catabolism [92].

C₆H₁₂O₆ → 2H₂ + CH₃CH₂CH₂COOH + 2CO₂

(6)

C₆H₁₂O₆ + 2H₂O → 4H₂ + 2CH₃COOH + 2CO₂

(7)

C₆H₁₂O₆ + 4H₂O → 8H₂ +CH₃COOH + 4CO₂

(8)

C₆H₁₂O₆ + 6H₂O→12 H₂ + 6CO₂

(9)

To implement H₂ strategies, tropical regions can utilize their natural resources to produce low-carbon H₂ from biomass technologies. In practice, green hydrogen production efforts should be directed toward developing bio-based hydrogen production by dark fermentation processes that use organic waste and biomass. These processes are not affected by the environmental variables and geographic locations that lead to intermittency and fluctuations in renewables.

Overall,

Table 1. Comparison of the H₂ production cost of water electrolysis vs. DF according to Ghasemi et al. [94], and references therein.

Method	Feedstock	Production Cost
Water electrolysis	Alkaline water electrolysis (AWE)	6 EUR/kg
	Proton exchange membrane (PEM) electrolysis	7 EUR/kg
Dark fermentation (DF)	Wastewater, agricultural waste, and molasses	2.7 USD/m3
	Food waste	1.02 USD/m3–2.29 USD/m3
	Organic biomass	2.57 USD/kg

reveals the economic advantages of using biomass over electrolysis methods in GHP, in addition to its environmental benefits. Additionally, capturing the collected biogenic carbon from biomass and removing it from the natural carbon cycle, such as in a gasification plant using carbon capture and storage (CCS) procedures with an extraction rate of 95%, generates negative emissions of −16 to −21 kg of CO₂eq per kg of H₂ [93].

7. Long-Term Stability and Support for Regulatory and Policy Frameworks

For GH to become a noteworthy portion of the global energy mix, regional and national availability of roadmaps, supportive regulations, policy frameworks, and strategies for the hydrogen sector development in clear and transparent terms are crucial to the approval and development of the hydrogen sector as an energy source. However, the development of hydrogen sector roadmaps in predominantly African countries is still in the early stages of adoption [48]. Incentives like carbon pricing, subsidies, and renewable energy goals can help drive GH adoption. The creation of these policies requires collaboration between governments, stakeholders, and researchers. Overcoming the technological boundaries and scalability challenges of GH adoption requires a multifaceted approach, with long-term policy stability and regulatory certainty being critical for attracting private investments in GH projects. Governments can implement helpful policies, such as long-term off-take contracts, feed-in tariffs, and fixed purchase fees, to reduce investment risks and ensure a stable market for GH. Policy frameworks should prioritize sustainability, environmental protection, and carbon reduction goals to offer a clear and reliable path for the GH industry [11]. GH adoption may face several challenges and barriers such as technological limitations, scalability issues, and the development of infrastructure, which would need more investments.

8. Conclusions

This work presented many issues related to GHP. Throughout, it addressed the most mature methods, particularly GHP from freshwater by electrolysis. African countries face problems of scarcity and disputes over freshwater. Moreover, the high infrastructure cost required for such technologies is an exorbitant cost that African countries burdened with debt cannot implement. In addition, it is necessary to provide the rare elements needed for electrolyzer operation. Due to tribalism and political instability, conflicts over land and its complex ownership systems persist. The expansion of pastures to meet the need for food further complicates the situation. All this and more requires the enactment of special laws and legislation to protect these investments, which donor countries will provide, increasing African countries’ financial burdens and debts.

Hence, to achieve energy security and address Africa’s energy gap, this work reveals the need to leverage the biomass available in the African continent for GHP as a regenerative RE source. Biomass is low in carbon intensity and is expected to mitigate GHG emissions and alleviate the climate change crisis. Financing renewable energy projects to produce green hydrogen from biomass is not capital-intensive, and developing countries can embark on large-scale development of such renewable energy without relying on international donors and investors.

According to the study analysis, it is crucial to intensify future research in biomass H₂ production technologies. Regarding industrialization prospects, biohydrogen production processes have simple H₂ generation, low costs, negative GHG emissions, sustainability, and eco-friendliness. Stakeholders can collaborate to launch clear and secure hydrogen policies and regulations to address challenges related to green hydrogen, such as investments, infrastructure, and technological limitations, to enhance energy security and promote economic growth. As global communities work toward meeting the Paris Agreement goals, international cooperation can support ongoing R&D, facilitate technology transfer, improve infrastructure, reinforce regulatory and policy frameworks, and enhance public–private partnerships, helping to establish hydrogen as a future fuel and smooth the transition to clean energy.

This paper suggests using biomass to obtain green hydrogen from the African continent in the short term and supporting the dark fermentation process with waste energy. This presents a double benefit by obtaining hydrogen at the lowest cost. In contrast, dark fermentation technologies are not affected by the intermittent nature of renewable energy, which means it is not always available when needed. Therefore, the expansion of the use of biomass in GHP creates successful partnerships, especially with the European continent, without putting pressure on the wealth of African countries or depleting their natural resources.