Air pollution impacts from carbon capture and storage (CCS)
Carbon Capture and Storage (CCS) consists of the capture of carbon dioxide (CO2) from power plants and/or CO2-intensive industries such as refineries, cement, iron and steel, its subsequent transport to a storage site, and finally its injection into a suitable underground geological formation for the purposes of permanent storage. It is considered to be one of the medium term 'bridging technologies' in the portfolio of available mitigation actions for stabilising concentrations of atmospheric CO2, the main greenhouse gas (GHG).
Within the European Union (EU), the European Commission's 2011 communication 'A Roadmap for moving to a competitive low carbon economy in 2050' lays out a plan for the EU to meet a long term target of reducing domestic GHG emissions by 80–95 % by 2050. As well as a high use of renewable energy, the implementation of CCS technologies in both the power and industry sectors is foreseen. The deployment of CCS technologies thus is assumed to play a central role in the future decarbonisation of the European power sector and within industry, and constitutes a key technology to achieve the required GHG reductions by 2050 in a cost-effective way.
A future implementation of CCS within Europe, however, needs to be seen within the context of the wider discussions concerning how Europe may best move toward a future low-energy, resource-efficient economy. Efforts to improve energy efficiency are for example one of the core planks of the EU's Europe 2020 growth strategy and the European Commission's recent Roadmap to a Resource Efficient Europe, as it is considered one of the most cost-effective methods of achieving Europe's long-term energy and climate goals. Improving energy efficiency also helps address several of the main energy challenges Europe presently faces, i.e. climate change (by reducing emissions of GHGs), the increasing dependence on imported energy, and the need for competitive and sustainable energy sources to ensure access to affordable, secure energy. While CCS is therefore regarded as one of the technological advances that may help the EU achieve its ambitions to decarbonise the electricity generating and industrial sectors by 2050, its implementation is considered a bridging technology and in itself should not introduce barriers or delays to the EU's overarching objective of moving toward a lower-energy and more resource-efficient economy. The technology should not, for example, serve as an incentive to increase the number of fossil fuel power plants.
In terms of emissions of pollutants, it is well known that efforts to control emissions of GHGs or air pollutants in isolation can have either synergistic or antagonistic effects on emissions of the other pollutant group, in turn leading to additional benefits or disadvantages occurring. In the case of CCS, the use of CO2 capture technology in power plants leads to a general energy penalty varying in the order of 15–25 % depending on the type of capture technology applied. This energy penalty, which offsets the positive effects of CO2 sequestration, requires the additional consumption of fuel, and consequently can result in additional 'direct' emissions (GHG and air pollutant emissions associated with power generation, CO2 capture and compression, transport and storage) and 'indirect' emissions, including for example the additional fuel production and transportation required. Offsetting the negative consequences of the energy penalty is the positive direct effect of CCS technology, which is the (substantial) potential reduction of CO2 emissions. It is thus important that the potential interactions between CCS technology implementation and air quality are well understood as plans for a widespread implementation of this technology mature.