Tuesday, July 15, 2008

EPA Issues Proposed Rules For GHG Geologic Sequestration

Jul 15: U.S. EPA announced its proposed rule to regulate carbon dioxide (CO2) geologic sequestration that can prevent industrial emissions the greenhouse gas (GHG). Secure, long-term underground storage of GHG is one way scientific innovation could lessen the effects of climate change. EPA Administrator Stephen Johnson said, "Today's proposal paves the way for technologies that would protect public health and help reduce the effects of climate change. With proper site selection and management, geologic sequestration could play a major role in reducing emissions of carbon dioxide into the atmosphere."

EPA's proposed regulation creates a consistent, national framework for the injection of carbon dioxide underground and protection of underground drinking water resources. The rule would create a new class of injection wells under the authority of the Safe Drinking Water Act's Underground Injection Control (UIC) program. The proposed rule builds on the existing UIC program, including extensive requirements to ensure wells are appropriately located, constructed, tested, monitored, and ultimately, closed with proper funding. It would apply to owners and operators of wells that will be used to inject carbon dioxide into the subsurface for the purpose of long-term storage.

Carbon capture and storage (CCS) is part of a portfolio of technologies available to reduce greenhouse gas emissions. EPA is coordinating with the Department of Energy on carbon sequestration research and development. EPA is requesting public comments on the proposed rule for 120 days following publication in the Federal Register.

EPA indicates that while the elements of the proposal are based on the existing regulatory framework of EPA’s Underground Injection Control (UIC) Program, modifications address the unique nature of CO2 injection for GS. The relative buoyancy of CO2, its corrosivity in the presence of water, the potential presence of impurities in captured CO2, its mobility within subsurface formations, and large injection volumes anticipated at full scale deployment warrant specific requirements tailored to this new practice.

CO2 is captured from flue gas produced by fossil-fueled power plants or industrial facilities, typically compressed to convert it from a gaseous state to a supercritical fluid, and transported to the sequestration site, usually by pipeline. The CO2 is then injected into deep subsurface rock formations through one or more wells, using technologies that have been developed and refined over the past several decades. To store the CO2 as a supercritical fluid, it would likely be injected at depths greater than approximately 800 meters (2,625 feet), where the pressure and temperature below the earth’s surface are sufficient to keep the CO2 in a supercritical state.

When injected in an appropriate receiving formation, CO2 is sequestered by a combination of physical and geochemical trapping processes. Physical trapping occurs when the relatively buoyant CO2 rises in the formation until it reaches a low-permeability layer that inhibits further upward migration, or when residual CO2 is immobilized in formation pore spaces. Geochemical trapping occurs when chemical reactions between the dissolved CO2 and minerals in the formation lead to the precipitation of solid carbonate minerals. Similarly, naturally-occurring CO2 deposits have been physically and geochemically trapped in geologic formations for millions of years.

The United States has abundant CO2 storage potential in onshore and offshore deep saline formations, depleted oil and gas fields, and deep, unmineable coal seams. These formations are present across the country and 95 percent of the largest stationary sources in the nation that emit CO2 are within 50 miles of a candidate CO2 storage reservoir.

On July 10, the House Energy & Commerce Committee, Energy and Air Quality Subcommittee, held a hearing on H.R. 6258, the Carbon Capture and Storage Early Deployment Act, that was introduced by Subcommittee Chairman Rick Boucher (D-VA) on June 12 [See WIMS 6/12/08]. The bipartisan legislation would advance the development and deployment of carbon capture and storage (CCS) technologies [See WIMS 7/10/08]. The bill, which has strong, bipartisan support, is designed to accelerate the time CCS becomes generally available by creating a Carbon Storage Research Corporation and a $1 billion annual fund to be distributed by the Corporation in the form of grants and contracts to governmental, academic and private entities for projects with the purpose of accelerating the commercial availability of CCS technologies.

Access a release from EPA with links to an audio file of the announcement (
click here). Access a prepublication copy of the proposed rule (click here). Access a fact sheet on the proposal (click here). Access EPA website on Geologic Sequestration of Carbon Dioxide for extensive information (click here). Access the H.R. 6258 hearing website for a webcast and links to all testimony (click here). Access legislative details for H.R. 6258 (click here). [*Energy, *Climate]

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