Deep down, beneath the bottom of the ocean, hydrogen gas (H2) is forming.
Once thought to be rare, a new model published in Geophysical Research Letters indicates that the gas beneath the seafloor is being produced at a rate that’s at least an order of magnitude higher than production under the continents.
The model takes into account a range of factors that would affect how much hydrogen gas is made and stored down below, including the quantity of serpentinized rocks — those that are chemically altered by water as they get pushed up by spreading tectonic plates. Hydrogen gas forms as a byproduct of this process.
It was previously believed that hydrogen gas only originated from slow-spreading plates because they produce the most serpentinized rock. Though fast-spreading tectonic plates contain “smaller quantities of this rock, our analysis suggests the amount of H2 produced there might still be large," study lead author Stacey Worman of the University of Texas at Austin says in a press release.
If large enough quantities of the gas were found beneath the oceans, it could be put to use as a substitute for fossil fuels. Burning hydrogen produces abundant energy and emits nothing but water vapor, making it a clean and green fuel.
Currently, the only means of obtaining the gas is through secondary processes. "You start with water, add energy to split the oxygen and hydrogen molecules apart, and get H2,” Worman explains. “You can then burn the H2, but you had to use energy to get energy, so it's not very efficient."
Mined hydrogen gas, on the other hand, would be a viable primary fuel source. But the scientists must first track the fate of the gas after it is produced. "Maybe microbes are eating it, or maybe it's accumulating in reservoirs under the seafloor. We still don't know," she says.
You might also like: The Two-Billion-Year-Old Nuclear Reactors of Gabon, Africa