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Pennsylvania State Geologists Building Zillow, but for Rocks

The Pennsylvania Geological Survey and those who partner with it are building a new web tool to help potential developers of carbon storage projects peruse the state's geological offerings.

Rocks Stones
(TNS) — The Pennsylvania Geological Survey and partners are building a web tool to help potential developers of carbon storage projects peruse the state's geological offerings.

Like a Zillow for rocks.

With almost $1 million from the U.S. Department of Energy, state geologists will be testing hundreds of rock samples and using that data to extrapolate if and where might be a good place to permanently store a climate menace that belches out of smoke stacks across the region.

Researchers are focusing on an area known as the Rome Trough, which is a long depression that stretches through portions of northern West Virginia and southwestern to central Pennsylvania. A trough typically sits between two fault lines.

The idea that unwanted carbon dioxide could be permanently sequestered in deep underground layers instead of being vented into the atmosphere and accelerating climate change has been around for decades.

Some Pennsylvania geologists have been working for at least that long to figure out if the rock layers under the Keystone State have hospitable pockets for long-term carbon storage. That is, if there are formations that are deep and porous and capped by unbroken slabs of impermeable rock that would act like a lid to keep CO2 from escaping.

Now, with billions of federal funds available for the development of such projects and many billions more in tax incentives — each metric ton of CO2 captured equals $85 in tax credits — Pennsylvania may be poised for carbon storage development.

First, though, interested parties will need to drill test wells. And before that, they'll need to figure out where to drill.

Despite Pennsylvania's century and a half of drilling holes in the ground and pulling out millions of years of geological history in core samples and drill cuttings, there are only seven wells that hit the basement rock. All are in the northwestern tip of the state, where the basement is the closest to the surface — at 5,000 to 6,000 feet underground.

In southwestern Pennsylvania, it is several times deeper.

"Where I'm sitting in Washington County and as you move farther south through Greene, it could be in excess of 20,000 feet deep," said Kris Carter, assistant state geologist and geologic resources division manager who is spearheading the Pennsylvania portion of the project.

"The error bar on that is pretty big," she warned.

The deepest well in Pennsylvania was drilled in 1973 in Somerset County. At 21,460 feet, it still didn't hit the basement.

"That depth is a lot of the reason why we don't have deep test wells here," said Michele Cooney, a geoscience supervisor with the Pennsylvania Geological Survey. West Virginia's Geological Survey and Battelle are other project partners.

Ms. Cooney will be the one selecting which of the 646 core samples available in the state's own collection will be tested for this project.

The researchers will subject existing cores and cuttings, most donated by the industry, to a series of tests to gauge how permeable or porous the different layers are, what kinds of minerals are found there, whether the rock is brittle and how much pressure it can withstand. These characteristics will help determine if a particular formation might be a good sponge for CO2 or a suitable cap rock.

The work will take two years and will culminate in decades worth of physical knowledge represented in a digital and publicly accessible format.

While Ms. Carter stressed that the goal of the work isn't to site projects but rather to "make sure that people have a good understanding of what's beneath their feet," the Department of Energy is definitely encouraging the development of CO2 capture and storage hubs.

DOE's goal, according to the funding announcement for this project, is to "accelerate the safe and socially equitable deployment of one of the nation's most promising decarbonization solutions."

Many states are trying to speed up the process of granting permits for CO2 injection wells, called Class VI wells. Right now, that's handled by federal environmental regulators. The process takes years and is still in its infancy — only one project has received a class VI permit to date. Dozens are pending, many in Louisiana, California, and Illinois.

None are in Pennsylvania. Ms. Carter said no company has yet applied to drill anything resembling a test well.

Yet the permitting application requires loads of technical data that isn't widely available yet. And that's partly where this effort comes in.

Carbon storage isn't the only point of interest underground. There's already a huge ecosystem of industrial activity in the subsurface, all of which informs not just where the geology might work for certain applications but where other human ventures might make good geology impractical to develop.

"The more you know about a particular layer of rock, the more confident you are in saying, 'Well, in this case, it can take CO2' or 'It can't.'"

© 2023 the Pittsburgh Post-Gazette. Distributed by Tribune Content Agency, LLC.