French geologist Emmanuel Masini knew nothing about venture capital and wasn’t trying to raise a round when he landed term sheets from three big-time investors — including Bill Gates.

Masini is the founder of Mantle8, one of a cohort of companies racing to find natural hydrogen: a gas locked under the Earth’s crust which, if it can be extracted, could change the world.

This small cohort of companies lean towards secrecy because – revealing any details on where they’re looking for hydrogen could tip off competitors.

But Mantle8 is, as Masini puts it, “coming out of the wood work,” today, announcing a $3.4m fundraise from Gates’ Breakthrough Energy Ventures and climate investor Kiko Ventures.

Interest in the sector is ticking up. In January, natural hydrogen startup Snowfox, a spinout from the University of Oxford, said it had raised an undisclosed sum from mining conglomerate Rio Tinto and oil and gas major BP.

In the US, Koloma, raised $245m in 2023 — the industry’s largest round to date — including backing from Breakthrough Energy Ventures.

A world-changing molecule?

Hydrogen is a clean fuel when burned, and many climate-friendly technologies rely on it, from green steel manufacturing to the production of cleaner shipping fuels.

The catch? The majority of the hydrogen used today is produced using fossil fuels and green hydrogen, which is produced using renewables, is expensive. It costs between $4 to $6 a kilo.That means every tonne of green steel needs between $200-$300 worth of hydrogen.

But tapping into deposits of naturally occurring hydrogen would change the equation significantly, with gas extracted from underground rather than needing to produce it. Estimates from Stanford University suggest natural hydrogen could cost $0.5 a kilo, a fraction of the price.

“Natural hydrogen is magic,” says Masini, who founded Mantle8 in September 2024. “If what we’re doing works, it’s going to be the most affordable hydrogen because nature is creating it.”

The first and only instance of natural hydrogen extraction was a deposit found in Mali, though questions over its purity remain.

Bill Gates previously shared his excitement for the potential of natural hydrogen, telling The Economist: “It could be gigantic or it could be a bust, but if it’s really there... wow!”

Don’t leave the crusts!

Mantle8 is developing three tools to help find natural hydrogen deposits.

The first is an AI tool that finds places with the right conditions for natural hydrogen formation. It’s looking for areas with a certain type of rock, called mantle.

Once a deposit has been located, Mantle8’s second tool creates an image of it beneath the surface, allowing researchers to calculate size and depth. Lastly, Mantle8 is working on tech that can measure the composition of the gas in the deposit.

“Mastering those three aspects of technology across the exploration value chain, from locating the deposit to production, then you can go faster, so you can deliver super efficiently,” says Masini.

Mantle8 has already located several deposits, including several in France.

Drilling into the earth’s crust is expensive, but Masini is confident that if Mantle8 can prove its found a deposit worth extracting, the capex to do so will follow.

The startup currently has a team of 8 geologists but plans to double that number across 2025. Whether they can be the first to find and safely extract the potential wonder gas remains to be seen.

“Delivering the first kilogram of clean, natural hydrogen is a pivotal point for the entire economy,” says Masini. “As a geologist, that’s my duty.”

Source: https://sifted.eu/articles/natural-hydrogen-mantle8-bill-gates

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