Introduction to Geological Storage of CO2
Carbon dioxide (CO2) is formed when fossil fuels—such as oil, gas, and coal— are burned to provide energy for industrial and domestic use. Fossil-fuel-related CO2 emissions account for more than 80 percent of greenhouse gas emissions in the United States and about one-third of those CO2 emissions come from coal or gas power plants. Unless properly captured at power plants and stored in deep geologic formations, CO2 is released into the atmosphere as a greenhouse gas, which contributes to global warming and ocean acidification.
Carbon capture, utilization and storage (CCUS) is considered a powerful tool to limit CO2 emissions into the atmosphere. It involves the process of capturing waste CO2 from large point sources, such as fossil fuel power plants, transporting it to a storage site, and injecting it in an underground geological formation, called a reservoir. The CO2 will stay in the reservoir for a very long time (more than 1,000 years). Geological reservoirs are chosen because they are of sufficient depth, thickness, porosity, and permeability to permanently and safely contain the CO2.
PNNL is working to advance the scientific understanding of how CO2 reacts with rocks and minerals when it is injected into the subsurface as part of the carbon storage process and to use this knowledge to advance the accuracy of models that will be used to predict its fate. Through various partnerships in the United States and abroad, PNNL is also contributing to the characterization of suitable geological sites for long-term storage of CO2 and the development of new monitoring and data management methods.More general information on CCUS can be found on the International Energy Agency website and on the National Energy Technology Laboratory website.