The idea of a vast, untapped reservoir of natural hydrogen, (1) one that could transform global energy systems, is as enticing as it is elusive. If a substantial, economically viable hydrogen field exists and can be exploited with minimal leakage to the atmosphere, it would mark a paradigm shift, offering a relatively clean energy source with low operational emissions. Unlike fossil fuels, which require carbon-intensive extraction and combustion, or green hydrogen, (2) which depends on large-scale renewable energy input, natural hydrogen could provide an energy supply that does not require conversion from electricity or fossil fuels, making it a potentially simpler and more continuous resource. (3) However, because hydrogen is an indirect greenhouse gas, any future exploitation must include robust monitoring strategies to quantify and minimize atmospheric losses in order to preserve its environmental advantages.

But there is a fundamental challenge: despite numerous documented hydrogen occurrences worldwide, no truly large-scale, commercially viable reserve has been found. This reality forces us to confront a crucial question, are we on the verge of discovering a new energy frontier, or will natural hydrogen remain a scientific curiosity (4) with limited economic impact?

To answer this, we must address two key uncertainties: Where should we look for a major natural hydrogen deposit? And what steps are needed to confirm its economic viability? The answer requires an exploration strategy that combines geological understanding, advanced detection techniques, and a willingness to take financial risks. If we fail to find a large reserve, alternative strategies, such as engineered subsurface hydrogen production (hydrogen farming (5)/stimulated hydrogen (6)), will become increasingly necessary, albeit at a higher cost.