Natural Hydrogen- a big new green energy resource?

Hydrogen is being talked up as a new clean zero carbon fuel. When you burn it you mainly just get water. But although the planet has a lot of it, in the form of sea/river water and fossil hydrocarbons, it’s hard to separate pure hydrogen gas out. The chemical processing of hydrocarbons is expensive and releases carbon dioxide gas, while the electrolysis of water is clean but not a very efficient use of power. 

However it has recently become clear that there may be a substantial natural geological hydrogen resource underground which might be extractable easily and cheaply. The most recent discovery is the largest so far.  Gas measurements taken at a bubbling pool almost 1km underground in a chromium-ore mine in Albania found 84% was pure hydrogen. It was estimated that the mine as a whole was releasing about 200 tonnes of hydrogen annually. There had been some explosions there in the past.  

The Albanian find may be the largest so far, but, as Hydrogen Insight has reported,  there have been several others around the world, including in NE France, Northern Spain and Southern Australia. And the hunt goes on for more. For example, the US Department of Energy has made $20m of grant funding available for technologies to measure and exploit natural hydrogen. University of Texas energy systems researcher Michael Webber told Science magazine, ‘If you look for it, you’ll find it’. If properly collected it could mean that naturally occurring H2 could be commercially exploited at low cost around the world. 

However, there is a debate about whether the resource would be large enough globally to matter.   The French research agency CNRS says ‘it is still too early to say whether natural hydrogen will take a significant place in our energy mix, or remain a niche curiosity. We also point out that natural hydrogen is not a renewable resource, in the sense that production rates are far too slow compared to the world's energy needs. In addition, these geological environments are often home to a deep and fragile biosphere that proliferates thanks in part to the presence of hydrogen’. 

Although, not everyone agrees about this. It is possible that these environments might actually be continually producing natural hydrogen quite rapidly. As Hydrogen Insight noted, it is all very speculative at this stage, but on the optimistic side, rough estimates from incidental hydrogen discoveries during oil & gas exploration, and seepage to the surface via so-called ‘fairy circles’, indicates that there could be enough natural hydrogen to meet anywhere from a quarter to five times the current global demand. It doesn’t have to be high purity hydrogen. Australian developer Gold Hydrogen says that ‘if natural hydrogen can be produced from the subsurface as part of a raw gas stream, then that raw gas can be processed at surface to yield a high purity hydrogen gas which can be used as an energy source’.

With the Albanian find providing a new emphasis, and exploratory drilling also now going on across much of Europe, as well as in Morocco and Brazil, and the USA (Nebraska, Arizona, and Kansas), the prospects for what has variously been called  ‘white’ or ‘gold’  hydrogen could be very good, as Fred Pearce has reported in a useful overview, which has also been relayed in Hydrogen-Central.com.  The review notes that Bill Gates has joined the hydrogen rush, making a major investment in a company that is exploring for hydrogen in the US Midwest. Gates also says ‘it’s on every continent’ and it’s certainly fascinating to see that a natural hydrogen power project was first pioneered in Mali in West Africa in 2012, and (given its relatively low extraction depth requirement) that it has an estimated extraction cost of less than $0.50 per kilogram, cheaper than any other source of hydrogen. 

Looking to the future, with experts like Geoffrey Ellis, a geoscientist at the USGS in Denver, talking about there being  something like 10 trillion tons of natural, or ‘geologic’, hydrogen buried underground worldwide, it could become a major renewable source globally . Ellis estimates that the Earth may generate hundreds of millions of tons of new natural hydrogen annually.

Of course, there could be problems. The Pearce review article quotes Stuart Haszeldine, a geologist at the University of Edinburgh, who says, ‘hydrogen is very leaky. It leaks almost as fast as it is produced, and certainly over geological time, it’s not accumulated to any great extent.’ And the review article also noted that, in any case, ‘many reserves will be too deep or remote to tap easily - around hydrothermal vents in the deep ocean, for instance’.  Extracting anything from underground also has risks, as we have learnt with fossil fuels, with, for example, escaped hydrogen gas potentially causing environmental problems. But assuming issues like that can be dealt with, the energy potential could be huge. The review article says that that, ‘if Ellis is right, then just a small fraction could meet the world’s needs for centuries’. And it says it could in places be tapped for less than $1,000 per ton,  according to  Emily Yedinak of the U.S. Department of Energy’s (DOE) Advanced Research Projects Agency-Energy, ‘making it substantially cheaper than manufactured hydrogen’.

As Pearce noted, ‘geologists have long known that processes in the Earth’s crust can make hydrogen gas from water. The most prevalent way appears to be serpentinization. This occurs when iron-rich rocks such as olivine are in contact with underground water and rust, capturing the oxygen to make iron oxides and leaving behind hydrogen.’ But he says ‘until recently this chemical reaction was seen as little more than a geological curiosity’. However, although Russian geologist Vladimir Larin ‘was making the case half a century ago that we live on a “primordially hydrogen-rich planet”,  few researchers showed much interest in exploring whether that assumption was true’. But now things may be changing and we may find at least part of the solution to our energy problem sitting under our feet...although it’s still too early to say for sure how much is there are how much it will cost to extract it.