DOE Funds Capture (and Use) of CO2

JULY 16, 2010

Although there is no magic bullet for reducing carbon dioxide (CO₂) emissions in the power industry, capturing carbon at the source—such as coal-fired power plants—could go a long way in cutting emissions while maintaining generation capacity. Recent rounds of funding from the U.S. Department of Energy (DOE) aim to develop CO₂-collecting technologies and put captured carbon to use, rather than storing it underground, which can be costly.

“Charting a path toward clean coal is essential to achieving our goals of providing clean energy, creating American jobs and reducing greenhouse gas emissions,” said U.S. Energy Secretary Steven Chu.

While coal-fired generation represents 33 percent of total U.S. CO₂ emissions, it accounts for 83 percent within the electricity sector, according to a white paper by CFC Senior Consultant Rod Nefsky. Trimming these emissions with currently available, post-combustion capture technologies is possible, although significant energy is required to do so. “It is estimated that a plant’s net capacity could drop by as much as 30 percent,” Nefsky said in the paper. “This means an existing coal plant rated at 300 mw would drop to 210 mw.”

Research and development projects that were awarded $67 million from DOE seek to reduce that energy “penalty,” in turn reducing costs. The research aims to reduce added costs to less than 30 percent for a new pulverized coal plant and less than 10 percent for a new advanced gasification plant. The research will focus on three technology areas that could be retrofitted to existing plants:

• Membranes. These specially manufactured materials allow certain gases to pass through while stopping others. A project testing the technology at the Arizona Public Service Cholla Power Plant will receive $14.7 million from DOE.
• Solvents. These liquids absorb CO₂ and can be added to absorber units, which flue gas is directed through. A variety of chemicals will be tested using DOE funds, including amine-, piperazine- and carbonate salt-based solvents.
• Solid sorbents. These solids, similar to solvents, absorb CO₂. One DOE-funded project will test this method of CO₂ capture, utilizing $11 million to develop a 1-mw pilot unit.

A second round of DOE funding totaling $4.4 million will investigate uses for CO₂ once it is captured. Transporting and permanently storing CO₂ is costly—citing MIT, Nefsky notes that annualized pipeline transportation and storage costs are estimated to be $5.50 per ton of carbon dioxide. The nation’s coal-fired power plants produced about 1.7 billion tons of CO₂ in 2009, according to the U.S. Energy Information Administration.

Potential uses for captured CO₂ include producing chemicals that can be used in industrial processes; creating a substitute for Portland cement in concrete; producing acrylate compounds, which are commonly used in plastics; and curing precast concrete.

Further Reading

Rod Nefsky’s white paper, “Carbon Capture and Sequestration,” provides an overview of current technology options and is available on CFC’s Member website.