THE energy and climate change universe is abuzz with the new developments around discovery of large deposits of natural or “white” hydrogen, with many commentators hailing it as great news and a potential game-changer in the battle against climate change. Fossil-fuel related carbon dioxide (CO2) emissions are today, even after so many international emissions control agreements and considerable installed capacity in renewable energy, still 91 per cent of global CO2 emissions. It is little wonder that news of any promising new source of non-fossil energy is greeted with much fanfare and excitement. However, as with several other supposed silver bullet solutions for the energy and climate crises, the reality turns out to be quite different upon closer examination or practical experience. Earlier articles in these columns by my colleague had looked at the different types of hydrogen, nicknamed with different colours based on source material and method of production, that are currently being manufactured as substitutes for fossil fuels, but then discussed how each of them turned out to be not as environment friendly as had appeared at first glance.

On the face of it, white hydrogen too appears to tick all the right boxes and offer a plentiful and clean energy solution. Going by past experience, a closer look is warranted.

THE BIG DISCOVERY
In July this year, two scientists at France’s National Centre for Scientific Research at the University of Lorraine were assessing methane levels in a disused coal mining basin, using a very sensitive new probe analysing gases dissolved in water in sub-soil rock formations when they came across low concentrations of hydrogen gas at around 200 metres depth. By itself, this was not surprising since hydrogen is often encountered, and in borewells. However, at 1,100 metres depth, the hydrogen concentration was 14 per cent, and then 20 per cent at 1,250 metres. The now surprised scientists estimated that there was a large hydrogen reservoir underneath, which they estimated at anywhere between 6 million and 250 million tons of what is now known as white or natural hydrogen. Efforts are now underway to drill down to 3,000 metres.

That is a very wide range, and the big questions are about the commercial viability of this and other possible reservoirs, are they really this large, how many other such deposits are there, and are current or modified technologies available that could enable quick deployment? Whatever the answers that may emerge in the next few years, for now the France finds and some earlier ones have triggered a rash of media articles, although a mini gold rush of sorts has been on for some years in different parts of the world, with several start-ups and legacy companies caught up in it.   

Of course, the presence of hydrogen in borewells has been known for many years, but was either ignored in the very early years because hydrogen’s usefulness was not appreciated at that time or because the quantities encountered were too small. Also, since nobody was really pursuing or prospecting for hydrogen reserves, there are very few historical or other records to guide contemporary scouting.

The current craze for white hydrogen was sparked off by a chance discovery in the village of Burakebougou in Mali in 1987 when a person drilling for water received when he leaned over the borehole while smoking a cigarette. The well was quickly capped and forgotten about till an oil company uncapped it in 2011 and reported that the well contained 98 per cent pure hydrogen. The gas was then used to generate electricity which continues to supply the village of around 4000 persons to this day. An article published about this in 2018 drew the attention of scientists and entrepreneurs.

Since then, reservoirs have been found in the US, Eastern Europe, Russia, Oman, Mali and France. Gold Hydrogen in South Australia scoured archives and found that a number of boreholes dug in the 1920s while prospecting for oil had encountered hydrogen but had no interest in it and so abandoned the bores.

Optimists estimate that there could be tens of billions of tons of hydrogen all over the world. Much of this may be very small deposits, or in remote places, under the sea and so on. But if even a small percentage is available in commercially viable quantities, it could be far more than the 100 million tons a year of quite energy – or carbon-intensive hydrogen currently produced, or the 500 million tons annually projected to be produced by 2050.

Two other salient points must be mentioned here, from the optimists’ point of view. First, white hydrogen is believed to be not a finite resource but produced continually by geological processes such as water reacting with iron-rich or other rocks with high basic content (the opposite of acidic) rocks or radiolysis, that is radiation-driven separation of hydrogen from water. Replacement time for what has been used could be equivalent to a human lifetime. Second, going by experience in Mali and in test bores elsewhere, white hydrogen could be produced at 1 dollar/kg compared to about 6 dollars/kg for “green hydrogen,” that is hydrogen produced using solar energy or other renewables.
  
THE SCEPTICAL VIEWPOINT 
A far less optimistic view is taken by several engineers and scientists about renewables, while conceding that white hydrogen could provide some relief from fossil fuels, especially compared to the dubious benefits of natural gas as a “transitional” fuel between oil or coal and, it is not the panacea that some people believe.
One such expert argues that, from a carbon standpoint, the various “colour-names” of hydrogen are misleading. Readers may recall, from earlier articles in these columns by my colleague as referred to earlier, that green hydrogen is made by electrolysis of water using renewable energy, the least carbon-intensive of all hydrogen making processes; grey hydrogen is made by steam reforming i.e., reaction with methane using fossil fuels, an energy and carbon-intensive process; blue hydrogen also by steam reforming of methane, but by capturing the carbon dioxide released during the reaction, which is carbon-intensive since it uses fossil fuels and uses a lot of energy in carbon sequestration besides being expensive. This expert then argues that only two colours are required to describe hydrogen produced using different raw materials and techniques, namely black and green for high-carbon and low-carbon hydrogen.  A group of professionals, academics and industrialists called the Hydrogen Science Coalition have collectively defined the dividing line at 1kg carbon dioxide equivalent or CO2e being used to produce 1kg hydrogen.
Several issues need to be considered to answer that question.
In what form is the hydrogen found? Is it almost pure hydrogen as found in Mali, or is it found in lower concentrations or mixed with other gases or liquids, and at what depth? What will it cost in money and carbon terms to extract pure hydrogen from this? Then there is the eternal issue of transportation, which also imposes money and carbon penalties. And finally, there is the question of quantities in which it will actually be available when the gold rush is over and a few prospectors return with a handful of gold dust.
All in all, a simplified answer is likely to be that, white hydrogen is certainly likely to be competitive as against black hydrogen, by whatever other colour or shade it is called. Several white hydrogen companies will certainly be viable, too. But it may not be the magic bullet some people always hope to find in the battle against climate change.