Rock Solutions: A Solid Underground CO2 Storage Engineering Challenge
An example of layering gravel, sand, and clay to prevent CO₂ from leaking.Copyright Mila Taylor, Seven Lakes High School, Katy ISD, Texas
Students explore how environmental engineers design underground systems to store carbon dioxide (CO₂) as part of climate change mitigation efforts. Working in teams, students build and test a physical model representing subsurface rock layers using sand, gravel, and clay. A baking soda and vinegar reaction generates carbon dioxide gas to simulate the movement and potential leakage of stored CO₂ within the system. After collecting quantitative data on leakage, students analyze the effectiveness of their designs and iteratively improve their models using the engineering design process. Through this activity, students investigate how properties such as porosity, permeability, and cap rock integrity influence the success of geological carbon storage.
Environmental engineers design carbon capture and storage (CCS) systems to reduce atmospheric CO₂ emissions. These systems inject CO₂ deep underground into porous rock formations, where it is trapped beneath impermeable cap rock layers. Engineers must carefully evaluate the porosity and permeability of underground rock formations, as well as the integrity of the cap rock, to ensure the CO₂ remains safely contained over long periods of time. By studying geology, fluid movement, and monitoring technologies, engineers can design storage systems that help mitigate climate change while protecting groundwater and surrounding ecosystems.
After this activity, students should be able to:
- Describe how porous and impermeable materials affect fluid and gas movement.
- Explain the role of cap rock in trapping gases underground.
- Collect and analyze quantitative data from a physical model.
- Apply the engineering design process to improve system performance.
- Evaluate trade-offs between storage capacity and leakage.