OSHTEMO TOWNSHIP, Mich. — The pressurized air able to pass through one rock can't always pass through another.
In large warehouse lined with rock samples from around the state, Dr. Autumn Haagsma demonstrated the difference with a bicycle pump, causing bubbles to burst forth from a piece of sandstone submerged in a beaker. A denser, darker rock allowed no such effervescence.
"The difference between a reservoir and a confining system," said Haagsma, hopelessly pushing down on the bike pump, attempting to force air into the denser rock to no avail.
The porous and not-so-porous properties of rocks are important to understanding the science of carbon capture and storage, says the assistant director of the Michigan Geological Survey at Western Michigan University.
In August, WMU and its partners were awarded a three-year, $5M grant from the Department of Energy to develop a "roadmap" of Michigan's underground rock formations as part of the federal government's effort to advance carbon capture and storage nationwide.
"The goal is that this is a transitional technology," said Haagsma, speaking about the sustainability-minded nature of carbon capture. "It's going to give us the time we need to make our processes more efficient."
In Michigan — a state that annually produces 70 million tons of carbon dioxide — researchers estimate its rock formations could hold 70 billion tons of the greenhouse gas.
"The goal is to store it deep enough so that you are meeting some pressure and temperature conditions," said Haagsma, explaining the process of harnessing the flighty form of matter.
When stored a half-mile below the surface, carbon dioxide behaves similarly to a liquid, according to Haagsma, and can be safely contained in porous rock formations. Meanwhile, dense rock surrounding these deposits can keep carbon dioxide from creeping to the surface and contaminating a water supply, for example.
"[At a greater depth] it becomes more manageable and you can understand how it's going to behave a little bit better, and control where it's going to flow better," Haagsma said.
In the Upper Peninsula, the area's volcanic rocks offer an "exciting" potential, as they could react with CO2 in such a way as to change it into a solid, a process called mineralization.
In the Lower Peninsula, Mount Simon sandstone is another "key formation" to target.
"I think my favorite thing about [the research] is the different types of storage, and those different types of storage happen at different places in Michigan," Haagsma said.
