The Catalyst Review January 2025 - 6

SPECIAL FEATURE
Feedstock/ source
H2 production technology/
mechanism
Natural gas
Steam methane reforming
Methane pyrolysis
Biomass
Biomass gasification
Biomass pyrolysis
Coal
Wind & water
Solar & water
Nuclear & water
S-I
Cu-Cl
Olivine & water
Hydrocarbons/ biomass/
waste & heat
Water & ionising
radiation
Organic compound &
anaerobicmicroorganisms
Photosynthetic bacteria/
cyanobacteria/ algae &
light & water
Electrolysis of water
Deep-seated/ thermal
decomposition
Radiolysis
Fermentation
Photosynthesis
Microbial/
biological
n/a 6[(Mg1.5 Fe0.5)SiO4] + 7H2O →
3[Mg3Si2O5(OH)4] + Fe3O4 + H2
n/a or CCS
n/a
CH4 + 1/2O2 → 2H2 + CO
2H2O → 2H2 + O2
C6H12O6 + 2H2O → 2CH3COOH+
2CO2 + 4H2
2H2O → 2H2 + O2
1.26-10.57
Coal gasification
CCS
Electrolysis of water
n/a
CCS
CCU
n/a
CCS
CCU
n/a
CO2
abatement/
elimination
technology
n/a
Example of main chemical
reaction(s)
CH4 + H2O → CO + 3H2
CH4→ 2H2 + C
C + H2O → CO + H2 (steam);
C + CO2 → 2CO (carbon)
CxHyOz → xC + y/2 H2 + CO +
CO2
C + H2O → CO + H2 (steam);
CO + H2O → CO2 + H2
2H2O → 2H2 + O2
Estimated carbon
intensity
(kg-CO2e/
kg-H2)
10.09-17.21
2.97-9.16
1.9-9.14
0.31-8.63
-11.66-17.55
TBD
Thermochemical cycle
CCS or n/a1
14.4-30.9
0.78-10.35
0.52-2.2
1.32-7.1
0.47-2.13
0.41-2.2
0.7-1.8
~0.4-1.5
Estimated
levelized cost
of production
(USD/kg)
1.36-2.45
1.22-2.26
1.03-2.16
1.21-2.19
2.27-3.60
1.48-3.00
0.96-1.88
1.40-3.60
3.56-10.82
3.34-14.87
3.29-8.21
1.47-2.71
1.47-2.70
Potentially <1
Table 1. Key hydrogen generation processes, their estimated carbon intensity and levelized cost of production. 1. Thermochemical cycles are
processes designed to produce hydrogen gas from water using a series of high-temperature chemical reactions driven by heat energy from an
external source (most often a nuclear reactor of concentrated solar power). However, in principle, fossil fuels could also be used. 5,6
Currently, the only confirmed reserve of natural hydrogen is located in Mali
As of now, among all reported instances of native hydrogen found in various locations worldwide (Figure 1),
only the Bourakébougou hydrogen accumulation in Mali has been thoroughly evaluated through appraisal
drilling and production testing, and it is currently in production. In particular, the first natural H2 well was
accidentally discovered in Mali in 1987 during a water drilling operation.1 While it took decades to appraise
and develop the almost pure (98%) hydrogen accumulation and start production in 2012, at the moment, the
Bourakébougou field powers around 4,000 homes in the nearby village.4
The Bourakébougou field is too small to be considered a game changer
Regarding the hydrogen wells in Mali, even though they produce nearly pure hydrogen, each well, assuming
a flow rate of 1,500 m³ per day, can only yield about 50 tonnes of H2 annually. This amount is equivalent to
roughly three barrels of oil per day.2 Consequently, this output is less than one-tenth of the energy produced
by a medium-sized wind turbine (ibid). At these production levels, thousands of wells would be required to
achieve the output of a relatively small gas field. Therefore, despite its significant scientific relevance and being
the first operational project for the commercial production of native hydrogen, the Bourakébougou case cannot
be regarded as viable for large-scale hydrogen generation and export, nor can it be considered a transformative
solution.
Large-scale production could become economically feasible with multiple discoveries of significant native
hydrogen resources
At the same time, if exploration efforts lead to numerous discoveries of substantial reserves of native hydrogen
similar to the successful case in Mali, large-scale production could indeed become economically attractive.
6
The Catalyst Review
January 2025
Naturally occurring
Manufactured
Origin
The Catalyst Review January 2025

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