VT Science Corner: Reaching for net zero with underground CO2 storage (2024)

Climate change is melting glaciers, increasing sea level, extending hurricane season, and intensifying wildfires.

Of course, Earth’s climate has undergone dramatic changes over its 4.5-billion-year history, but industrialization has accelerated the rate of climate change by pouring billions of tons greenhouse gases into the atmosphere each year.

Greenhouse gases include water vapor, carbon dioxide, methane and nitrous oxide, among others.

These gasses trap heat that would otherwise leave the planet. Since heat makes Earth habitable, we need greenhouse gases to survive. But we all know the old saying, too much of a good thing …

In terms of climate change, “too much of a good thing” is excess carbon dioxide gas or CO2.

The industrial revolution gave us the steam-powered engine, which required thermal energy (heat) to produce steam. This led to the rampant use of fossil fuels, such as coal, oil, and natural gas.

Over the last 150 years, fossil fuels became the central drivers of industrialization worldwide, powering economies through electricity production and transportation on a massive scale. But burning fossil fuels produces CO2, and lots of it.

How can we grow our economy without growing CO2 emissions?

This is an all-hands-on-deck problem. Energy efficiency is part of the solution, where we simply use less energy to achieve the same outcome — such as more miles-per-gallon. Also, carbon-free energy sources such as nuclear, solar, wind and geothermal produce less CO2.

Still, certain industrial processes such as steel, cement and ammonia production cannot be fully decarbonized by changing energy sources.

That’s where a technology known as carbon capture and geologic sequestration (CCS) could come into play. CCS separates CO2 from industrial waste gas and then uses injection wells to pump the CO2 back into deep geologic formations, where it becomes isolated from the atmosphere.

The technology needed for CCS is not new. We’ve been separating gases from flue stacks for a very long time.

Water scrubbing for gas separation and purification has been used for more than 100 years; and there are now far more sophisticated methods to carefully separate and purify CO2 from industrial waste gas.

And we know that geologic formations are really good at storing fluids (or gasses) for long periods of time. Oil and gas deposits are the most obvious examples.

In order to commercialize CCS technology, the Bipartisan Infrastructure Law (BIL) and Inflation Reduction Act offers industrial operators substantial incentives to offset expenditures required for deployment.

Much of the BIL funding is being distributed through the U.S. Department of Energy to support efforts for identifying geologic formations suitable for CO2 storage.

Here at Virginia Tech, our research team is working on projects that may unlock new geologic formations for CO2 storage.

We are members of the Southeast Regional CO2 Utilization and Storage Acceleration Partnership, a federally funded program to address key technical barriers for geologic carbon storage throughout the southeast United States.

We are studying carbon storage in deep limestone formations of South Florida, as well as the more complicated geologic structures here in Southwest Virginia. Our team is also partnering with Colorado School Mines to study the CO2 mineralization potential of iron-rich rocks in the western U.S.

And we are partnering with colleagues in the Virginia Tech Department of Mining and Minerals Engineering and the Virginia Department of Energy to assess the potential for carbon mineralization in mine waste throughout the Mid-Atlantic.

Carbon capture and geologic sequestration will not fully decouple economic growth from runaway CO2 emissions. But this technology is likely to play an important role in decarbonizing the hard-to-abate industrial sectors, particularly if we can find geologic formations that will store CO2 near major CO2-emitting industrial facilities.

As the world reaches for technological solutions to its most vexing problems, Virginia Tech students, faculty, and researchers are using science to find solutions. Geologic carbon sequestration may turn out to be one of these solutions.