Scientists Say Earth Has Made Enough Hydrogen to Power Humanity. Here’s How to Find It.

There’s growing optimism that huge amounts of natural hydrogen are stored deep underground. Now, researchers have identified the key geological features that could help us hunt for the clean-burning fuel.

Hydrogen is a leading contender to replace fossil fuels because it only produces water when burned in combustion engines or used to power fuel cells.

We already produce a substantial amount of hydrogen for industrial purposes, such as during the production of fertilizer. But most hydrogen is generated from hydrocarbons, leading to waste gases that add 2.4 percent to global carbon-dioxide emissions.

Efforts are underway to create greener sources of the gas by using renewable electricity to split water into hydrogen and oxygen. But the technology is still far from being commercially viable.

Recently, the discovery of large deposits of underground hydrogen has led to hopes there may be significant natural sources of the clean fuel. Last year, researchers estimated Earth’s crust could hold 5.6 trillion metric tons (6.2 trillion tons) of the gas, though they admitted much of this is probably impractical to extract.

Now, another team has identified the key ingredients required to discover large, commercially viable deposits of hydrogen. In a paper in Nature Reviews Earth & Environment, they outline the process likely to produce significant amounts of the gas and what rock structures allow it to collect in places we can reach.

“One successful exploration recipe that is repeatable will unlock a commercially competitive, low-carbon hydrogen source that would significantly contribute to the energy transition,” lead author Chris Ballentine, from Oxford University, said in a press release.

The researchers estimate that in the last billion years, Earth has produced enough hydrogen to support humanity’s energy needs for at least 170,000 years, though much of this may have been lost to natural processes.

The gas mainly forms during chemical reactions, like when water oxidizes iron-rich rocks and gives off hydrogen as a byproduct or radiation from rocks splits water molecules into hydrogen and oxygen. Interestingly, the researchers rejected a popular theory that hydrogen is supplied to the crust by the fluid mantle layer below.

For a useable deposit to form, the researchers say you need a combination of three ingredients: a hydrogen source, rock formations that can hold the gas to form a reservoir, and a natural seal that prevents the hydrogen from escaping.

“One place that is attracting a lot of interest is in Kansas where a feature called the midcontinental rift, formed about one billion years ago, created a huge accumulation of rocks (mainly basalts) that can react with water to form hydrogen,” Ballentine told LiveScience. “The search is on here for geological structures that may have trapped and accumulated the hydrogen generated.”

Some of the most promising formations include those that used to be at the bottom of the ocean but were later pushed onto land by geological processes or those formed from hardened lava after volcanic eruptions. The researchers have formed a company called Snowfox Discovery to start hunting for large hydrogen deposits.

But it’s important to remember that even if we do discover significant amounts of the gas, it won’t be a slam dunk for the environment. Hydrogen is highly flammable and must be stored at high pressure, leading to safety concerns that may restrict where it can be used.

That also means it’s not compatible with the pipes and tanks used to transport and store fossil fuels, so we’d need to build a huge amount of new infrastructure. Hydrogen is also much less energy-dense than fossil fuels, limiting its use in areas like aviation.

Regardless, having an abundant source of clean-burning fuel would certainly be a major boon for our efforts to fight climate change. With any luck, this new guide for hydrogen prospectors will make that a reality in the near future.