Publication Overview
The IEA Greenhouse Gas R&D Programme has issued reports assessing the cost of CO₂ capture technologies for power generation using all of the three main types of process, i.e. pre-combustion, post-combustion and oxy-combustion capture. A report has also been issued on the implications if other impurities are co-captured along with the CO₂. In most of the variants of these processes there is an economic or practical limit to the percentage of the CO₂ which can be captured. There has been increasing interest in recent years in the concept of “zero emission power generation” which would in essence be the complete 100% capture of all CO₂ and other emissions of gaseous components, principally the sulphur and nitrogen oxides. A study has thus been proposed, building on the previous work, to explore this concept in more depth. In formulating this study it is considered more appropriate to consider the concept as providing “near zero” emissions to the atmosphere since thermodynamic limitations make complete capture inappropriate for some of the contending processes.
Publication Summary
Oxy-combustion processes can be adapted to provide near zero emission performance of CO₂ capturing power plant without significantly increasing cost of electricity. Pre and post combustion processes can be adapted but at marginal costs which are excessive and cannot easily reach the close to 100% possible with oxy-combustion.
Life cycle considerations limit the overall reduction of emissions in the full fossil fuel to electricity energy chain because of emissions caused by transport and production. These are sufficient to question the wisdom of increasing capture of CO₂ emissions at power plants beyond the economic optimum even for oxy-combustion. Also the “zero emission” advantage of oxy-combustion is significantly diminished as a result of these additional emissions.
Capture processes already eliminate many of the toxic emissions and further increases in CO₂ capture percentage would yield little or no further advantage with respect to SOx, NOx, particulate or mercury emissions
