Natural hydrogen: Fluctuation in time
Could wells refill themselves on human time scales?
What this tab covers How availability changes over seconds, days, seasons, years and longer, how predictable it is, and what that means for the plants that use it.If hydrogen is generated continuously underground, wells could be partly recharged on human time scales; the Mali field has produced for years without measurable pressure loss. The evidence is still thin and the question is under active research.
Variation by time scale
| Time scale | What happens | How large |
|---|---|---|
| Years (field behaviour) | No pressure decline observed at Bourakebougou, suggesting ongoing replenishment3 | About 1,300 m3 a day for seven years with no reported pressure drop |
| Years (seepage) | Continuous degassing from faulted ophiolite rocks4 | At least 200 t a year at Bulqize, Albania |
| Decades (exploration) | Hydrogen discovered by accident in Mali in 1987; deliberate exploration only since the late 2010s3 | 18 of 24 exploration wells in Mali (2017-18) found hydrogen |
| Geological | Generation by serpentinisation and radiolysis continues as long as water meets suitable rock13 | Formed wherever water reacts with iron-rich rock or is split by natural radiation |
| Microseconds (lightning, for comparison) | Lightning releases its energy in a fraction of a second at millions of volts, far too briefly and erratically to capture14 | Average flash energy about 3.9 GJ (about 1.1 MWh), NASA estimate for US flashes |
How predictable it is
Unknown at scale. Output from a single well appears steady, but no one yet knows how fast reservoirs recharge, how large they are, or how production will decline over decades.
Natural hydrogen sits between a stock and a flow. Accumulations trapped over long periods behave like a gas field, while active generation may refill them; the balance between the two determines whether a field depletes like natural gas or behaves more like a geothermal reservoir.
Production costs are also untested: stakeholders suggest USD 0.5-1.0 per kg, against USD 3-8 per kg for hydrogen from renewable electrolysis, but these are estimates rather than market prices.
Sources
- The natural hydrogen field without pressure depletion GEO ExPro, 2023
- Discovery of a large hydrogen reservoir in an underground mine in Albania ISTerre, Universite Grenoble Alpes / CNRS, 2024
- How is geologic hydrogen formed? US Geological Survey, 2025
- GLM Estimates of LNOx Over the Continental US: Ground and Cloud Flash Differences (Koshak, AMS 2021) NASA Marshall Space Flight Center (NASA Technical Reports Server), 2021