Carbon capture and sequestration (CCS) is perhaps commercially viable but not proven at commercial scale, according to 100 clean-energy experts that recently released their recommendations to the White House: "Powering Forward: Presidential and Executive Agency Actions to Drive Clean Energy in America."

The authoring committee, a group of CEOs and energy experts led by former Colorado Governor Bill Ritter, Jr., focuses primarily on renewable energy and natural gas, but does take aim at the assumptions the U.S. Environmental Protection Agency (EPA) is using to justify its proposed requirement for CCS at new coal-fired power plants.

The EPA is precluded by law from requiring the use of technologies that have not been demonstrated commercially.

CCS can also be applied to natural gas-fired power plants and industrial facilities such as fertilizer plants.

The International Energy Agency reports (IEA, 2011) that electricity from coal power plants with carbon capture costs 74 percent more than reference plants without capture.  IEA also opines that CCS is an emerging technology in the power sector, where it has not been demonstrated at large scale.

The Congressional Research Service technology assessment (2013) states that the primary drawbacks to existing carbon capture technologies are their high cost and large energy requirements, and the lack of any commercial, full-scale plants using the technology.

The U.S. Department of Energy (DOE) is the major supporter of capture and sequestration research, development and demonstration. Its program aims to develop by 2020 a portfolio of CCS technologies for large-scale deployment. In 2009 it selected three large-scale CCS demonstration projects that aimed to capture and store 6.5 million tons of CO2 per year. The three have completed phase I: research and planning, and are starting phase II: design, construction and operation.

• Decatur, IL, project to inject CO2 into the Mount Simon sandstone. Archer Daniels Midland and the Illinois State Geological Survey project is awaiting a Class VI injection well permit.
• Lake Charles, LA, project for CO2 use in enhanced oil recovery (EOR) in West Hastings oil field, TX. Leucadia has completed preliminary designs. Construction of the petroleum coke gasification plant, which will be the source of CO2, should begin in early 2014.
• Port Arthur, TX, project by Air Products and Chemicals, Denbury, Valero Energy and the University of Texas Bureau of Economic Geology, will provide CO2 from steam-methane reformers for enhanced oil recovery. The project began CO2 capture and EOR in 2013.

Outside the U.S., Sleipner, a North Sea deep subsea injection project by Statoil has been injecting CO2 since 1996. It was the world's first commercial CO2 storage project. By May 2008 10 million tons of CO2 had been injected. Injection currently costs $17 U.S./ton CO2.