The potential of carbon capture and storage to mitigate global climate change is still widely contested; in this study CCS’s potential benefits are quantified and its efficacy is examined under several different scenarios (Stone et al. 2009). When estimating the possible benefits of CCS, the most important variables that need to be addressed are the storage retention time of the reservoirs used, the energy penalty of the operation, the extent that CCS technology will be deployed, future emissions scenarios, and the degree of climate sensitivity. The study finds that CCS technology is worthwhile, and has the potential to significantly curb rising temperatures, especially in the short term.— Shanna Hoversten
Stone, E., Lowe, J., Shine, K., 2009. The impact of carbon capture and storage on climate. Energy & Environmental Science 2, 81–91.
E.J. Stone and colleagues analyzed the potential benefits of CCS under a variety of circumstances by combining a model of the carbon cycle with a model for CCS storage potential and propensity for leakages. One of the strengths of this study is that Stone et al. took into account the atmospheric sensitivity to increased CO2, which had previously been ignored in similar models. The study modeled climate change reductions under two IPCC scenarios—the A1F1 which constitutes a fossil fuel intensive world, and the B1 which represents a world driven by clean, resource-efficient technology. The effects of variable retention times, energy penalties, fractions of fossil fuel emissions released from a single plant, and the fraction of global fossil fuels emissions subject to CCS are then modeled.
The result is that there are considerable benefits to deploying CCS technology, especially in the short term. It is much easier to achieve a break-even point for shorter time spans than longer time spans due to the small but constant leakage that will occur from the storage site. Even so, it may be beneficial to apply this technology in the short term while we are still looking for alternative energy sources that do not emit such a high concentration of CO2. The importance of these short-term measures will also depend on climate sensitivity, as the maximum temperature reduction benefits of CCS will increase with heightened climate sensitivities.
Retention time was found to have a significantly greater effect on the efficacy of CCS projects than did other factors such as energy penalty. Even large energy penalties can be tolerated provided that the retention time of the storage site is adequate. However that does not mean that storage sites should only be considered if they have the ability to store the CO2 for a 10,000 year duration; one of the most interesting findings of this study was that the use of storage reservoirs previously considered to have insufficiently low leakage rates may still have the potential to confer climate benefits. Storing the CO2 for even a short period of time may allow for stabilization of atmospheric CO2 concentrations which would in turn reduce climate sensitivity and mitigate substantial rises in temperatures.