ENERGY SECURITYThe Potential for Geologic Hydrogen for Next-Generation Energy

Hydrogen, you may recall from your school days, is a gas. It is considered the cleanest fuel, because burning it only produces heat and pure water. Engineers have even created a way to use it to generate electricity in the hydrogen fuel cell. In brief, this works because the fuel cell binds hydrogen and oxygen together to make water, generating electricity in the process.

Although its primary use as an energy source today is in rocket fuel, hydrogen is expected to play an important role in future energy systems. It may offer a solution for reducing the carbon footprint of processes that cannot easily be electrified, such as long-distance flights and industrial heating. The catch is, the vast majority of hydrogen is manufactured using natural gas through a process that consumes energy and releases large amounts of carbon dioxide into the atmosphere.

Scientists have known for some time that hydrogen also occurs naturally, generated through geologic processes. Tapping into natural sources would eliminate the problem that dogs manufactured hydrogen, because it wouldn’t release those large amounts of carbon into the atmosphere. There’s just one problem: there’s little scientific information available about how much hydrogen is out there, or where it might be found.

A Global Perspective
To get a sense of the amount of hydrogen gas that the Earth may be storing, USGS research geologist Geoffrey Ellis enlisted the help of his Energy Resources Program colleague Sarah Gelman to develop a global resource model. Before they could use a model to estimate the amount of hydrogen available, they had to advance scientific understanding about the behavior of hydrogen in the subsurface. The pair used existing knowledge of analogues such as natural gas to fill the gaps in existing knowledge and develop their hydrogen model. 

“Using a conservative range of input values, the model predicts a mean volume of hydrogen that could supply the projected global hydrogen demand for thousands of years,” Ellis said. 

However, he quickly cautions, “We have to be very careful in interpreting this number, though.  Based on what we know about the distribution of petroleum and other gases in the subsurface, most of this hydrogen is probably inaccessible.” 

In other words, hydrogen supplies are too deeply buried, or too far offshore, or in accumulations that are too small, making it highly unlikely they could ever be economically recovered.

The good news is, if even a small fraction of this estimated volume could be recovered,