Injection and Geologic Sequestration of Carbon Dioxide (Paperback) | Released: 02 Feb 2020

For several decades the federal government has funded efforts to explore the feasibility of mitigating the release of greenhouse gases (GHGs) while burning fossil fuels as a source of energy. Carbon capture and storage (CCS)-the process of capturing manmade carbon dioxide (CO2) at its source, such as a coal-fired power plant, and storing it before its release into the atmosphere-has been proposed as a technological solution for mitigating emissions into the atmosphere while continuing to use fossil energy. Underground carbon storage, known as geologic sequestration, is the long-term containment of a fluid (including gas or liquid CO2 in subsurface geologic formations). Long-term storage of CO2 can also occur incidentally through enhanced oil recovery (EOR), a process of injecting CO2 into an oil or gas reservoir that can significantly increase the amount of oil or gas produced. The U.S. Department of Energy (DOE) leads the federal government's carbon storage research and development (R&D) as part of the agency's fossil energy programs. The agency conducts research on geologic sequestration and EOR, and carries out the Regional Carbon Sequestration Partnerships (RCSP) program-a set of public-private partnerships across the United States to deploy testing and development of CO2 injection and storage. To date in the United States, nine projects have injected large volumes of CO2 into underground formations as demonstrations of potential commercial-scale storage. Four of these projects are actively injecting and storing CO2-one in an underground saline reservoir to demonstrate geologic sequestration and three in oil and gas reservoirs as part of EOR. Currently, while numerous large-scale storage R&D projects are ongoing in the United States, none of the projects injecting CO2 solely for geologic sequestration are operating in a commercial capacity. The Safe Drinking Water Act (SDWA), administered by the U.S. Environmental Protection Agency (EPA), provides authorities for regulating underground injection of fluids and serves as the framework for regulation of geologic sequestration of CO2 and EOR. The major purpose of the act's Underground Injection Control (UIC) provisions is to prevent endangerment of underground sources of drinking water from injection activities. EPA has promulgated regulations and established minimum federal requirements for six classes of injection wells. In 2010, EPA promulgated regulations for the underground injection of CO2 for long-term storage and established UIC Class VI, a new class of wells solely for geologic sequestration of CO2. The well performance standards and other requirements established in the Class VI rule are based on the distinctive features of CO2 injection compared to other types of injection. Two Class VI wells, both in Illinois, are currently permitted by EPA in the United States. No state has issued a permit for a Class VI well. CO2 injection for EOR is conducted using Class II wells (associated with oil and gas production). SDWA also authorizes states to administer UIC programs in lieu of EPA, known as primacy. For Class VI CO2 geologic sequestration wells, only North Dakota has primacy. Most oil and gas producing states have primacy for Class II wells and regulate these wells under their own state programs. Congress has supported carbon storage via underground injection through recent legislation directing DOE to expand R&D activity and increasing the federal tax credit for underground carbon storage. A policy challenge that Congress may face with underground carbon storage is balancing protection of underground sources of drinking water with supporting and encouraging the development of cost-effective CCS technology. If Congress were to explore future policy in this area, Members may consider the potential health and environmental risks (beyond any related risks to underground sources of drinking water) not addressed by SDWA.