CO₂ Capture and Storage

1. What is carbon dioxide capture and storage?

• 1.1 What is CO₂ capture and storage and what could its applications be?
• 1.2 What role could CO₂ capture and storage play in the fight against climate change?

1.1 What is CO₂ capture and storage and what could its applications be?

Carbon dioxide (CO₂) is a greenhouse gas that occurs naturally in the atmosphere. Human activities are increasing the concentration of CO₂ in the atmosphere thus contributing to Earth’s global warming. CO₂ is emitted when fuel is burnt – be it in large power plants, in car engines, or in heating systems. It can also be emitted by some other industrial processes, for instance when resources are extracted and processed, or when forests are burnt.

Carbon dioxide capture and storage (CCS) is one of the techniques that could be used to reduce CO₂ emissions from human activities. It could be applied to emissions from large power plants or industrial facilities.

The process involves three main steps:

1. capturing CO₂, at its source, by separating it from other gases produced by an industrial process
2. transporting the captured CO₂ to a suitable storage location (typically in compressed form)
3. storing the CO₂ away from the atmosphere for a long period of time, for instance in underground geological formations, in the deep ocean, or within certain mineral compounds.

Some of the technologies needed for this process are more mature than others. By mid-2005, three commercial projects had already been implemented that store CO₂ captured in underground geological formations as part of oil and gas extraction or processing projects. More...

1.2 What role could CO₂ capture and storage play in the fight against climate change?

Most scenarios for global energy use project a substantial increase of CO₂ emissions throughout this century in the absence of specific actions to mitigate climate change. They also suggest that the supply of primary energy will continue to be dominated by fossil fuels until at least the middle of the century.

Therefore, techniques to capture and store the CO₂ produced combined with other technological options could play a role in the fight against climate change.

However, no single technology option will provide all of the emission reductions needed to stabilize greenhouse gas concentrations in the atmosphere at a level that prevents dangerous interference with the climate system.

Other technological options to stabilize greenhouse gas concentrations in the atmosphere include:

• reducing energy demand by increasing energy efficiency;
• switching to less carbon-intensive fuels (from coal to natural gas, for example),
• increasing the use of renewable energy sources and/or nuclear energy (each of which, on balance, emit little or no CO₂);
• enhancing natural carbon sinks (such as forest); and
• reducing greenhouse gases other than CO₂ (such as methane).

CO₂ capture and storage would be an option for developed countries which need to reduce CO₂ emissions and have significant sources of CO₂ suitable for capture, access to storage sites and experience with oil or gas operations. But there are many barriers to deployment in developing countries. Creating conditions that would facilitate diffusion of this technology to developing countries would, therefore, be a major issue for the adoption of CO₂ capture and storage worldwide. More...