carbon capture and storage

carbon capture and storage
Name	Carbon Capture and Storage
Caption	The Sleipner gas field in the North Sea was a pioneer in large-scale geological storage.
Other names	CCS, Carbon Sequestration

carbon capture and storage. It is a process designed to mitigate climate change by capturing carbon dioxide emissions from industrial sources, transporting them, and injecting them into deep geological formations for long-term isolation from the atmosphere. The technology is considered a critical component in strategies to achieve net zero emissions, particularly for sectors that are difficult to decarbonize, such as cement production and steelmaking. Major international bodies, including the Intergovernmental Panel on Climate Change and the International Energy Agency, have highlighted its importance in global climate scenarios.

Overview

The fundamental concept involves intercepting CO2 at the point of emission before it can enter the Earth's atmosphere. This process is distinct from natural carbon sinks like forests or oceans, representing a technological form of carbon sequestration. The development of this field has been significantly advanced by projects like the Sleipner gas field operation, managed by Equinor, and research initiatives supported by the United States Department of Energy. The goal is to prevent the release of greenhouse gases from major industrial activities, thereby reducing the cumulative impact on global warming.

Technologies

Capture technologies are primarily categorized into post-combustion, pre-combustion, and oxy-fuel combustion. Post-combustion systems, often using amine-based solvents, separate CO2 from the flue gas of power plants, a method demonstrated at facilities like the Boundary Dam Power Station in Saskatchewan. Pre-combustion capture involves gasifying fuel, a process integral to Integrated Gasification Combined Cycle plants, and is a focus of research at institutions like the Massachusetts Institute of Technology. Oxy-fuel combustion burns fuel in pure oxygen, resulting in a more concentrated CO2 stream. Transportation is typically via pipeline networks, such as those operated by Denbury Resources, or by ship. Storage relies on injecting CO2 into deep geological formations, including depleted oil and gas fields and saline aquifers, with monitoring to ensure containment.

Applications and projects

Major applications are found in fossil fuel-based power generation, natural gas processing, and heavy industries like chemical plants producing ammonia or ethanol. The Petra Nova project in Texas was a landmark application on a coal-fired plant. In the North Sea, the Northern Lights project, a joint venture by Equinor, Shell, and TotalEnergies, is developing infrastructure for cross-border CO2 transport and storage. Other significant initiatives include the Gorgon gas project in Australia and the planned Net Zero Teesside cluster in the United Kingdom. Enhanced Oil Recovery, where CO2 is used to increase extraction from oil fields, has been a commercial driver, particularly in the Permian Basin.

Environmental and economic considerations

Proponents argue it is essential for meeting the targets of the Paris Agreement and can create employment in regions with legacy industrial infrastructure. However, the process is energy-intensive, potentially increasing local air pollution and water consumption at capture sites. The economic viability heavily depends on carbon pricing mechanisms, such as the European Union Emissions Trading System, and government incentives like the 45Q tax credit in the United States. Lifecycle analysis must account for potential leakage from storage sites, which could negate climate benefits and pose risks to local ecosystems and groundwater.

Policy and regulation

National and international frameworks are evolving to govern this technology. The London Protocol has been amended to allow for cross-border transport of CO2 for sequestration. In the United States, the Environmental Protection Agency regulates geological storage under the Underground Injection Control program. The European Union has developed the CCS Directive to establish standards for safe storage. International collaboration is fostered through forums like the Carbon Sequestration Leadership Forum and missions under the Mission Innovation initiative. Support from entities like the World Bank and the Asian Development Bank is also shaping policy in developing economies.

Challenges and limitations

Key challenges include high capital expenditure and operational costs, which have led to the cancellation of projects like Kemper Project. Public acceptance, or the "Not In My Backyard" sentiment, particularly regarding pipeline safety and storage integrity, remains a significant social hurdle. Technical risks involve the long-term integrity of caprock formations and the potential for induced seismicity. There is also debate that widespread deployment could perpetuate reliance on fossil fuels and divert investment from renewable energy sources like solar power and wind power. Monitoring, verification, and accounting for stored CO2 over centuries present unresolved legal and technical questions.

Category:Climate change mitigation Category:Industrial processes Category:Energy technology