For this study, we use the long-term yearly average of global irradiation at optimum tilt angle for Burkina Faso, covering the period from 1994 to 2018. These data are from the WORLD BANK database [24] . The Burkina Faso presented in Figure 3 is the studied area. It is a Sahelian country located in Western Africa between latitudes 9˚ and 15˚ north, and longitudes 6˚ west to 3˚ East. Burkina Faso has a surface area of 274,200 km² and is characterized by significant interannual climate variability.

Electrolysis is the process by which water is split into hydrogen and oxygen using electricity or electrical energy. The electrolyzer Figure 4 , is the instrument that transforms a portion of the electrical energy that is given into chemical energy. In this study, we utilize the PEM electrolyzer because of its proven efficiency and popularity in the energy industry [9] . This method uses a solid polymeric PEM to separate the anode (oxidation electrode) from the cathode (reduction electrode) [9] . Green hydrogen is the name given to the hydrogen generated when the energy used to power the electrolyzers originates from a renewable source [25] . There is also grey hydrogen produced from fossil fuels and blue hydrogen produced from natural gas with carbon [4] . The reason for the use of PEM is its high rate of hydrogen synthesis, purity of gases, and energy efficiency [26] . Numerous research [27] - [32] estimated hydrogen generation using the PEM. With an efficiency of 75% [27] - [32] , the electrolyzer is expected to use 53 kWh to produce 1 kg of hydrogen [32] .

Solar PV arrays, a power conversion system, and a water electrolysis system make up the solar energy-to-hydrogen conversion system. The water electrolysis conversion process in the solar energy-to-hydrogen conversion system uses a PEM electrolysis system with 54 kWh per kilogram of hydrogen [27] . A crystalline silicon panel with an efficiency of 17% and a panel density of 0.337 (acceptable density to minimize shading) [33] is the solar PV technology in use [32] . Equation 1 defines the electricity generated by the solar energy conversion system:

$E_{solar}\left(\text{Wh}\cdot {\text{year}}^{-1}\right)=GTI\cdot S_{coverarea}\left({\text{m}}^2\right)\cdot {\eta }_{PV}{\eta }_{pc}{\eta }_{pf}{\eta }_{derating}$ (1)

Equation 2 governs the mass of hydrogen (kg) generated by the solar energy-to-hydrogen conversion system, while Equation 2 calculates the swept area availability of the solar farm.

Table 1 presents characteristics of input parameters used in Equation 1, Equation 2, and Equation 3 for the solar energy-to-hydrogen conversion analysis. To estimate the potential for producing hydrogen from electrical energy, the following scenarios are considered: use of the available suitable area of each region, and we consider only 10% of solar energy from these areas.

$M_{H_2}\left(\text{kg}\cdot {\text{year}}^{-1}\right)=\frac{E_{solar}{\eta }_{elec}}{E_{elec}}$ (2)

$S_{coverarea}=\text{suitable area}\left({\text{m}}^2\right)\times \text{PV panel\_spacingdensity}$ (3)

$S_{coverarea}=\text{suitable area}\left({\text{m}}^2\right)\times \text{PV panel\_spacingdensity}$ (4)

Hydrogen energy has the potential to help re-electrify rural areas, mainly in villages without grid electricity [22] . More, electricity produced from hydrogen could replace fossil fuel-based energy sources in the home and industrial sectors, such as gasoline or diesel generators [36] . It is estimated that 1 kg of GH₂ may provide 20 kWh of power with present technology (4.5 Mt GH₂/90 TWh) [37] , while in another article [29] , according to thermodynamic properties, 1 kilogram of hydrogen contains 33.3 kWh ≈ 120.1 MJ (lower heating value). Equation 5, which uses hydrogen for re-electrification, shows the potential for this process. We use that 20 kWh of energy can be produced from 1 kilogram GH₂.

$R{E}_p\left(\text{GWh}\right)=\frac{20}{1000}\cdot M_{H_2}$ (5)

One kilogram of GH₂ can replace 3.785 L of petrol [36] , while 1 kg of hydrogen has the same energy content as one US gallon of gasoline [38] . We use the following equation (Equation 6)to assess the quantities of petrol that could be avoided by using GH₂.

$PR\left(\text{L}\right)=M_{H_2}\times 3.785$ (6)

This part aims to estimate the amount of CO₂ and CO (Equation 7)that could be avoided if hydrogen were used instead of petrol (or gasoline).

${\text{CO}}_2\text{or}\text{CO}\left(\text{kg}\cdot {\text{L}}^{-1}\right)=PR\cdot S{E}_F$ (7)

$S{E}_F$ is the specific emission factor of the corresponding greenhouse gas. For CO₂, $S{E}_F=2.3\text{kg}\cdot {\text{L}}^{-1}$ while $S{E}_F=0.00413\text{kg}\cdot {\text{L}}^{-1}$ for CO [39] .

As illustrated in Figure 5(b) , the mean solar PV potential energy over the entire country has been presented on an annual basis for the period 1994 - 2018. This result is derived from Equation 1, using global irradiation at optimal tilt present in Figure 5(a) . The distribution of potential from solar-powered electrolysis across Burkina Faso is uniform, with elevated levels observed in the northern regions of the country. The results of the suitable area, annual solar PV energy, and Green Hydrogen GH₂ potential estimation are displayed in Table 2 , while the yearly Potential energy production by region is shown in Figure 6 . Using only 10% of solar PV which corresponds to 2591.85 MWh.year⁻¹ for the entire region, the annual hydrogen production potential can reach up to 36 tons.year⁻¹. The highest and the lowest annual hydrogen production potential are 6.12 and 0.38 tons.year⁻¹. Concerning the potential of GH₂ energy, the production reaches 720 MWh.year⁻¹. The highest and the lowest annual GH₂ energy production potential are respectively 122.4 and 7.6 MWh.

The results of the estimated amount of annual petrol (or gasoline) replacement with hydrogen by each region are displayed in Figure 7 . Figure 8 and Figure 9 show the quantity of annual greenhouse gases CO₂ and CO emissions that could be prevented. It is estimated that the quantity of petrol (or gasoline) is 136252.7 liters. Using hydrogen produced from 10% solar PV energy, the maximum and minimum amounts of petrol that can be substituted with hydrogen are respectively 23153.72 and 1440.72 liters. In accordance with the stipulated conditions, the replacement of petrol (or gasoline) has the potential to prevent 313.38 tons of CO₂ on a national scale. In terms of CO, the utilisation of hydrogen has the potential to engender a reduction of 562.71 kg on a national scale. The substitution of petrol for hydrogen in the re-electrification of rural communities lacking adequate energy access has the potential to contribute to a reduction in greenhouse gas (CO₂ and CO) emissions in Burkina Faso.

This phenomenon has the potential to contribute to a reduction in the year’s total CO₂ emissions, which part driven by the combustion of fossil fuels (7.02 MtCO₂), as reported by [40] . This gradual emission reduction, when implemented across all sectors, has the potential to enhance the country’s climate change mitigation efforts and carbon neutrality goals. As part of its energy policy, Burkina Faso has undertaken a significant transition towards renewable energy sources. This approach is part of a commitment to guarantee universal access to electricity, a crucial objective for the country’s socio-economic development. As part of this study, two agencies have been created: the National Agency for Renewable Energy and Efficiency (ANAREE) and the Burkina Faso Agency for Rural Electricity (ABER). With this study, only 10% of solar PV energy production for GH₂ production for re-electrification and replacing fossil fuel generators with hydrogen fuel cell generators will provide environmental benefits and reduce air pollution, as evidenced by the reduction of CO₂ and CO emissions. This integration can drive the vision of Burkina Faso’s carbon neutrality and net-zero goal by 2060 (Climate Action Tracker 2023), bringing economic benefits through additional revenue generation from GH₂ exports, fostering the development and creation of new jobs within the energy sector, and contributing to the achievement of the United Nations’s Sustainable Development Goals (SDGs), particularly SDG 7 (Affordable and Clean Energy) and SDG 13 (Climate Action), which emphasized the importance of sustainable energy solutions in achieving broader development objectives.

However, it is important to note that certain limitations may potentially compromise the validity of the study results. Initially, it is important to note that the data used for the computation of global irradiation at optimum tilt encompasses a comparatively limited period (1994-2018). In contrast, the climatological data sets require three decades of observations. Secondly, the study has not adequately evaluated the areas most suitable for the generation of PV energy. Further investigations could entail the use of raster and polygon data pertaining to water bodies, protected areas, and forests, with a view to achieving greater accuracy in the evaluation of suitable land. This would facilitate the identification of viable land within the spatial model. Finally, for a period of several months, Burkina Faso has been divided administratively into 17 regions. This is not updated because the data is of a shapefile nature. For that we use the previous shapefile which, we use the previous shapefile, which comprises thirteen regions.