IEA Energy Technology Essentials: CO2 Capture and Storage

IEA Energy Technology Essentials: CO2 Capture & Storage

Overview:

The International Energy Agency (IEA) Energy Technology Essentials provide a comprehensive overview of carbon dioxide capture and storage (CCS), a critical technology aimed at reducing greenhouse gas emissions from various industrial sectors.

Key Processes:

1. CO2 Capture:
   • Pre-combustion: Utilizes fossil fuel treatments like coal gasification and natural gas reforming, followed by shift conversion.
   • Post-combustion: Involves capturing CO2 from flue gas in supercritical pulverized coal combustion (SC/PCC) plants and natural gas combined cycle (NGCC) plants. Oxyfuel combustion offers another method, producing nearly pure CO2 for easy separation.
   • Natural Gas Wells: CO2 is separated directly from the gas stream during extraction.

Technical Details:

• Capture Efficiency: Pre-combustion methods are currently promising, offering application to integrated coal gasification combined cycle (IGCC) and natural gas combined cycle (NGCC) plants.
• Post-combustion: Utilizes chemical absorption from flue gas in SC/PCC plants and NGCC, and oxyfuel combustion, which involves additional costs for oxygen supply.
• Separation Methods: Membrane-based techniques are under development for both pre- and post-combustion processes.

Costs and Performance:

• Costs: Capture costs vary widely, from $30 to $90 per tonne of CO2, depending on technology, CO2 purity, and location. Transport costs are generally $1-$10 per tonne per 100 km, and storage plus monitoring costs $2-$5 per tonne.
• Impact on Electricity Cost: Adds approximately 2-3 US cents per kilowatt-hour (kWh).
• Projected Costs: By 2030, CCS costs are anticipated to be around $25 per tonne of CO2, reducing the impact on electricity cost to 1-2 US cents per kWh.

Status and Potential:

• Demonstration and Deployment: CCS is being demonstrated in a few industrial storage facilities with capacities over 3 million tonnes per year. Many oil fields utilize CO2 for enhanced oil recovery (EOR).
• Geological Storage Potential: Global geological storage capacity is estimated to equal at least 80 years of current CO2 emissions.
• Barriers: High costs of large-scale demonstration projects, operational costs, and permanent safe storage. Need for regulatory frameworks, government policies, and incentives for emission reduction, along with public acceptance.

Future Trends:

• Integration of Technologies: Multiple CCS technologies are likely to coexist, requiring further research and development to enhance efficiency and reduce costs.
• Innovation: Development of ion-transport membranes and new oxygen production techniques for oxyfuel combustion is expected within 5-10 years.
• Environmental Benefits: Oxyfuel combustion has potential to reduce NOx emissions and possibly sulfur emissions, although its long-term effects are still under investigation.

Conclusion:

CO2 capture and storage is a pivotal technology in combating climate change, offering significant potential for reducing emissions from industrial processes. Despite technical advancements and cost considerations, effective deployment and widespread adoption face substantial challenges, primarily economic and technological, necessitating continued research and policy support.