Carbon Capture and Sequestration: Silver Bullet or Black Hole?
Covered by Courtney Mitchell
Moderator:
Jeff Johnson, Senior Correspondent, Chemical & Engineering News
Panelists:
Bruce Braine, Vice President, Strategic Policy Analysis, American Electric Power
Thomas Feeley, Technology Manager, National Energy Technology Lab, U.S. Department of Energy
Sarah Forbes, Senior Associate and CCS Specialist, World Resources Institute
Coal is responsible for 36% of carbon emissions in the United States and 50% of electricity is produced by coal fired power plants. Though the panel was a very diverse group, all agreed that carbon capture and sequestration (CCS) has the potential to save the coal industry in a world of possible CO2 caps. Sarah Forbes opened the discussion with a history of the carbon sequestration process. She emphasized that risk assessment and site selection are the most important aspects in that there must be sufficient cap rock and the capacity to hold carbon. After injection, the CO2 dissolves in the rock pores and forms solid carbonates over time which causes the risk of leakage to decrease over time. Though this process is somewhat understood, the environmental, health, safety and economic risks associated with CCS are still being researched.
Carbon sequestration can be used for any source of CO2, not just coal. In fact, Bruce Braine stated that the natural gas and oil companies have been doing it for years on a very small scale. The success and effects of large scale operations are still very uncertain. However, Sarah Forbes referred to current projects where carbon has been successfully captured, liquefied, transported, sequestered and permanently trapped. She states that global cooperation of the research community is vital to the success of CCS.
Before one can inject carbon into the ground, it must be captured which is a very expensive process. This is the most complicated issue because capturing carbon requires an average of 32% of the energy created at a power plant. If post combustion capture techniques were utilized at existing pulverized coal power plants, it is estimated that energy costs would increase by 40%. Using oxygen combustion at these plants would possibly be much less expensive. Pre-combustion techniques applicable at integrated gasification combined cycle plants would require energy costs to be increased by 25%. American Electric Power is retrofitting the Mountaineer plant in New Haven, West Virginia with new chilled ammonia technologies which would use only 15% of the plants energy to capture carbon. If the 2009 initial operation goes well, the company hopes to begin using this technology on a commercial scale by 2012.
All panelists agreed that CCS is not a silver bullet but that including this in a portfolio accompanied by nuclear power, renewable energy, improved energy efficiency, advanced coal generation, andplug-in hybrid electric vehicles will significantly reduce carbon emissions and hopefully ward off climate change.