Storage Versus Renewables

There is intense debate about the wisdom of diverting resources to develop CO₂ capture and storage which might be used alternatively to develop more renewable energy. Considerations to be taken into account are

• The feasibility of a rapid conversion to renewables in the time frame required to limit climate change.
• The potential speed with which deep cuts could be made with capture and storage technology.
• The extra cost of implementing storage would give a competitive advantage to renewables which might be more effective than direct subsidies
• The potential for environmental damage from very large scale implementation of renewables.
• The reduction in energy efficiency of resulting from capture and storage activities which increases reliance on fossil fuel. More efficient or renewable technologies, while not delivering the same deep cuts in emissions certainly help reduce dependency on fossil fuels.

Public Acceptability

Implementing carbon dioxide capture and storage on a commercial scale will be a massive undertaking involving major modifications to power stations, construction of an extensive additional high pressure transport pipeline system, exploration for and development of underground storage reservoirs with associated CO₂ injection wells. It is to be expected that there will be some local public concern about general safety, possible disruption during construction, the routing and location of pipelines, wells and storage sites. Additionally there may be wider public concerns about the general acceptability of CO₂ storage on a large scale. It is too early to know how extensive such concerns will be. Demonstration projects, such as that proposed at Ketzin and others around the world, which are already in operation, all help towards understanding of this issue.

Sustainability

Approximately one third of all CO₂ emissions due to human activity come from fossil fuels used for generating electricity, with each power plant capable of emitting several million tons of CO₂ annually. A variety of other industrial processes also emit large amounts of CO₂ , for example oil refineries, cement works, and iron and steel production. These emissions could be reduced substantially, without major changes to the basic process, by capturing and storing the CO₂. There are many ways in which CO₂ emissions can be reduced, such as increasing the efficiency of power plant or by using natural gas instead of coal as a fuel. However, most scenarios suggest that these steps alone will not achieve the required reductions in CO₂ emissions. The capture and storage of CO₂ from fossil fuel combustion could play an important part in solving this problem. In the long-term, the world's energy system may have to be based on non-fossil energy sources. Decarbonising the use of fossil fuels, by capture and storage of CO₂, would help the transition to a future carbon-free energy system.

Regulatory and Legal Issues

Any form of injection of CO₂ into reservoirs under the sea raises issues as to the interpretation of provisions under several international treaties. The movement of CO₂ over national borders raises issues of whether the CO2 or any other components which might be present in it classify as wastes upon which there are legal restrictions. Owner ship and responsibility for stored CO₂ in the long term is an unresolved issue.

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