Carbon capture and sequestration (CCS) is an emerging technological development which enables coal to be used while avoiding significant greenhouse-gas emissions. The most effective way to combat the predicted impacts of climate change is to limit carbon dioxide (CO₂) emissions, particularly from coal-burning power plants. CCS is ready to be deployed now but is expensive. Although CCS presents challenges, environmental concerns can be mitigated through careful project planning and execution. If the current administration successfully passes and funds a climate bill, CCS will achieve the incentive needed for commercialization.
There are several risks associated with CCS. Some of the most common risks include long-term leakage of CO₂ back to the atmosphere either through an inadequate seal or a seal damaged through operation. These high-volume leaks may produce an asphyxiation hazard to people or ecosystems. Potential escape mechanisms include unplugged wells, faults, fractures, and insufficient permeable caprock. Another concern is the contamination of drinking-water aquifers caused by CO₂ leaks. A method to mitigate this risk is to prohibit any CCS activities above the lowest-drinking aquifer. Finally, another concern is that CO₂ injected into brine reservoirs could pollute future drinking-water alternatives.
The best tool to manage risk is the regulatory framework promulgated for CCS projects at the state or federal level. These regulations must be grounded in a thorough, scientific understanding of the risks involved and ensure they are managed properly. Rules must be flexible, adaptive, performance-based, and include requirements for site characterization, site selection, and long-term monitoring
Amy Hardberger, Managing the Risks of CO2 Sequestration, Sᴏᴜᴛʜᴡᴇsᴛ Hʏᴅʀᴏʟᴏɢʏ (Sept./Oct. 2009).