What is Carbon Sequestration?

Carbon sequestration encompasses the processes of capture and storage of CO₂ that would otherwise reside in the atmosphere for long periods of time. DOE is investigating a variety of carbon sequestration options. Geologic sequestration involves the separation and capture of CO₂ at the point of emissions followed by storage in deep underground geologic formations. Terrestrial sequestration involves the net removal of CO₂ from the atmosphere by plants and microorganisms and its storage in vegetative biomass and in soils. There is significant opportunity to use terrestrial sequestration both to reduce CO₂ and to obtain the ancillary benefits such as habitat and water quality improvements that often result from such projects. The DOE is focusing its efforts for terrestrial sequestration on increasing carbon uptake through reforestation and amendment of minelands and other damaged soils. In addition, regional efforts are examining terrestrial sequestration through various land management techniques including no-till farming and wetland restoration.

It is expected that large numbers of new power plants and fuel processing facilities will be built in the coming decades, in both the developing world as well as in some areas of the developed world, such as the U.S. and Canada. These new facilities, along with existing plants having the potential for being appropriately retrofitted, will create ample opportunities for deploying efficient and cost effective CO₂ capture technologies. DOE's CO₂ capture efforts seek to cost effectively capture and purify CO₂ using post-combustion, pre-combustion, or oxy-combustion technologies for carbon capture.

Geologic sequestration is defined as the placement of CO₂ into an underground repository in such a way that it will remain permanently stored. DOE is investigating five types of underground formations for geologic sequestration, each with different challenges and opportunities for CO₂ sequestration: (1) mature oil and natural gas reservoirs, (2) deep unmineable coal seams, (3) deep saline formations, (4) oil- and gas-rich organic shales, and (5) basalt formations.

The process of CO₂ sequestration includes monitoring, mitigation, and verification (MM&V) as well as risk assessment at the sequestration site. DOE's MM&V efforts focus on development and deployment of technologies that can provide an accurate accounting of stored CO₂ and a high level of confidence that the CO₂ will remain permanently sequestered. Effective application of these MM&V technologies will ensure the safety of sequestration projects with respect to both human health and the environment, and provide the basis for establishing carbon credit trading markets for sequestered CO₂. Risk assessment research focuses on identifying and quantifying potential risks to humans and the environment associated with CO₂ sequestration and helping to ensure that these risks remain low.

DOE's Carbon Sequestration Program

DOE's Carbon Sequestration Program involves two key elements for technology development: (1) Core R&D and (2) Demonstration and Deployment. The Core R&D element contains five focal areas for carbon sequestration technology development: (1) CO₂ Capture, (2) Carbon Storage, (3) Monitoring, Mitigation, and Verification, (4) Non-CO₂ Greenhouse Gas Control, and (5) Breakthrough Concepts. Core R&D is driven by industry's technology needs and is accomplished through laboratory and pilot-scale research aimed at developing new technologies and new systems for GHG mitigation. Core R&D provides technology solutions which support Demonstration and Deployment in the areas of Regional Carbon Sequestration Partnerships, FutureGen, and other commercial opportunities. Experiences with Demonstration and Deployment provide "lessons learned" which are used by Core R&D in developing further technology solutions.

In addition, DOE is part of an international collaboration in the area of carbon sequestration, participating in the Carbon Sequestration Leadership Forum (CSLF). The CSLF is an international climate change initiative that is focused on the development of improved, cost-effective technologies for the separation and capture of CO₂ and for its transport and long-term safe storage. The purpose of the CSLF is to make these technologies available internationally and to identify and address wider issues relating to carbon capture and storage.

DOE's Carbon Sequestration Program is developing a portfolio of technologies with great potential to reduce GHG emissions. The Carbon Sequestration Program's primary concentration is on dramatically lowering the cost and energy requirements of pre- and post-combustion CO₂ capture. The goal is to have a technology portfolio by 2012 for safe, cost-effective and long-term carbon mitigation, management and storage, which will lead to substantial market penetration after 2012. In the long-term, the Program is expected to contribute significantly to the President's goal of developing technologies to substantially reduce GHG emissions.