The Potential for Geologic Hydrogen for Next-Generation Energy
there would likely be enough hydrogen across all the global deposits to last for hundreds of years. Ellis is convinced that the amount of hydrogen in the Earth’s interior could potentially constitute a primary energy resource.
“The key,” he said, “is to understand if hydrogen exists in significant accumulations that can be economically accessed, and if so, how to find these resources.”
Taking Lessons from Oil and Gas
To begin to understand the potential for hydrogen accumulation, scientists need a better geologic model to understand how the hydrogen forms, where it comes from within the rock layers, and where it ends up.
Ellis notes, “We’re fortunate that we are not starting from scratch here.”
Relying on his background in petroleum geology, he is working to create a model that uses the petroleum system approach.
The petroleum system is a conceptual model designed for understanding the occurrence of petroleum within geologic basins. It has been used by petroleum geologists for decades to effectively guide oil and gas exploration and to derive accurate assessments of undiscovered petroleum resources.
The model helps geologists analyze the geologic factors that must come together to effectively form a petroleum accumulation. Picture a geologist who is following a series of clues to solve a puzzle. First, a source rock must contain organic material capable of generating petroleum. Then, the geologist must consider any pathways the petroleum could follow as it escapes the source rock and migrates through other rock layers. In addition, the geologist must identify any porous reservoir rocks where the petroleum could accumulate. Last, the geologist must evaluate whether there are rocks in the vicinity that could have sealed the fluid in place, often for millions of years. If any of these components fail, then the geologist can deduce that a petroleum accumulation wouldn’t form.
The Hydrogen System
To adapt the petroleum system model for hydrogen accumulations, geologists must identify how natural hydrogen forms within rock layers, what types of natural processes might affect the hydrogen once formed, and how the hydrogen can get trapped in rock layers along its way to the surface.
Geologists already know that there are dozens of natural processes that generate hydrogen but understanding hydrogen resource potential requires identifying which of those mechanisms are capable of generating large quantities of the gas. One such process that scientists generally agree upon happens when groundwater interacts with iron-rich minerals like olivine. (Olivine is a magnesium iron silicate that has a green hue