You are here

How to Store Carbon

March 17, 2016 - 3:30pm


Carbon capture and storage is a key component of the U.S. Department of Energy’s approach to combatting climate change. The concept is simple: capture CO2 before it leaves a power plant so it can’t trap heat in the atmosphere. Energy innovators have developed many technologies to separate CO2 from the gas stream of coal-fired power plants, but what happens once CO2 has been captured? CO2 storage is a little more complicated than simply locking the captured gas into a vessel and throwing away the key.

Carbon storage involves transporting the captured CO2, usually in liquid form via pipeline, and injecting it deep underground in geologic formations. Energy researchers study these extensively to ensure each formation is suitable for long-term storage. Choosing the right location is critical to the long-term safety and viability of a carbon storage project. The storage formation must have a porous, permeable layer to hold the CO2 and an impermeable overlying sealing layer, or “caprock,” which will prevent the CO2 from making its way to the surface or overlying groundwater resources. During and after injection, the CO2 plume is monitored as it migrates within the storage target to ensure that is effectively contained.

Monitoring and assessment can be a complicated task. Subsurface geologic systems used to store CO2 are formed by natural processes over millions of years, which makes them inherently complex and variable. Given this inherent uncertainty, how do we ensure geologic storage of CO2 is safe, permanent and worthwhile?

We need to develop a science-based methodology to quantify environmental risk of carbon storage projects over time.

The National Risk Assessment Partnership (NRAP) is a consortium across five National Labs working on exactly this methodology. The information it provides will help guide site selection, operational decision making and risk management.

Led by the National Energy Technology Laboratory (NETL), NRAP relies on the Energy Department’s expertise across multiple disciplines -- including reservoir engineering, geology, geophysics, statistics and environmental engineering -- to help remove barriers to widespread deployment of CO2 storage.

Recently, NRAP released a cutting-edge set of seven modeling tools designed to help evaluate environmental risks of large-scale carbon storage operations. You can find the detailed list here

The new tools are now undergoing extensive review from volunteer beta-testers including members from industry, regulatory agencies, universities and other research organizations, such as the NETL-managed Regional Carbon Sequestration Partnerships. The NRAP project team will then implement improvements based on the beta-testers’ feedback, with the final tool release expected by fall of this year.

The NRAP toolset will ensure carbon storage is safe, viable and worthwhile. The tools will help regulators quantify risks in order to evaluate specific projects. And they will increase investor confidence in carbon capture and storage projects since long-term costs can be estimated more easily. In the end, this is a win for carbon storage. And a win for carbon storage is also a win in the fight against climate change.
Editor’s Note: This post was created by the National Energy Technology Laboratory, one of the Department of Energy’s 17 National Labs.