The global concern about the depletion of traditional energy resources and climate change has led to the promotion of various sustainable, environmentally friendly, and reliable energy resources such as hydrogen. Hydrogen holds great potential as a clean and versatile energy carrier. It is considered a clean energy carrier because, when used in fuel cells, its only byproduct is water vapor. The history of hydrogen dates to ancient times as seen in Figure 1 below. There are different types of hydrogen based on the method of production and the amount of greenhouse gases emitted. The popularly known hydrogen types are highlighted in Figure 2. However, the understanding of its properties and potential uses has evolved significantly over the centuries. Different methods are being exploited to produce hydrogen and aid decarbonization.
History of Hydrogen
Types of Hydrogen
Nowadays, most of the hydrogen generated today including blue hydrogen is produced from natural gas through steam reformation such that the accompanying greenhouses are captured. Green hydrogen on the other hand is environmentally friendly and produced through water electrolysis. It has the potential to decarbonize energy-intensive industries such as transport and chemical, but, the cost of green hydrogen is still high, and the demand for renewable energy cannot be met.
The drawbacks of green hydrogen have led to recent scientific discoveries about white hydrogen. White hydrogen is a naturally occurring hydrogen that can be found geologically in subsurface deposits and produced during fracking. It is extracted and purified without the release of carbon emissions. It was revealed that there is more white hydrogen beneath the earth’s surface than previously believed. Currently, about 35 countries including Germany, Mali, Netherlands, the United States, the United Kingdom, Australia, and Japan are exploring the potential of white hydrogen.
In contrast to green hydrogen, white hydrogen can be extracted at a lower cost by drilling through the earth’s surface without the need for other renewable energy sources for electrolysis or the expense of an electrolyzer. In a recent statistic, the cost of producing grey, blue, and green hydrogen ranges from $0.98 to $2.93 per kilogram, $1.8 to $4.70 per kilogram, and from $4.5 to $12 per kilogram respectively. To provide context, an estimate by researcher Viacheslav Zgonnik suggests that white hydrogen may be the cheapest alternative to gas at $0.1 to $1 per kilogram, even less expensive than the currently predominant grey hydrogen.
Also, white hydrogen is readily available as a renewable, non-polluting energy if found alone compared to grey or blue hydrogen as the process of generation only includes extraction and purification. The process is simple compared to other types of hydrogen production. However, white hydrogen is rarely pure, it is mostly found combined with other elements or gases such as Nitrogen, Methane, and Helium. For instance, while over 99% of H2 explored from the Bougou-1 field in Mali is pure at the surface, some other regions have it in a fraction of 80% H2, 20% CH4, 70% H2 + 30% N, etc. This means that further process would be required to extract pure hydrogen. In addition, this also signifies that the depth of capture, concentration, and output of white hydrogen would vary substantially across different locations globally. Hence, discovering white hydrogen in a particular location does not imply that it is commercially viable and that a value chain needs to be created there.
In conclusion, while white hydrogen has the potential to become the clean energy of the future for an affordable, reliable, sustainable, and clean energy option for all; research is yet to ascertain if the process of drilling to extract white hydrogen has any negative environmental impact in addition to the quantity that can be extracted. Therefore, nations need to start incorporating white hydrogen into their national hydrogen policies and strategies to utilize its potential fully. This will increase research and development of white hydrogen