A Graphical Technique for the Comparison of Carbon Dioxide Capture and Sequestering Costs in Coal-based Electrical Generation with Natural Gas Combined Cycle Technology under
North American Conditions

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John H. Walsh
Energy Advisor


The object of this paper is to present a simple graphical technique to illustrate the range of possibilities for the capture and sequestering of carbon dioxide from coal-based generation in relation to the natural gas-based combined-cycle process (NGCC) under North American conditions. The publication of an interdisciplinary study by the Massachusetts Institute of Technology in June of 2003 entitled The Future of Nuclear Power provided comparative data on the levelized cost of electricity produced in the NGCC process as a function of the delivered cost of natural gas. Data on conventional nuclear generation in PWRs included an assessment of the advances expected in the latter technology over the years for comparison. Cost data was also provided for electricity generated in modern coal-based pulverized fuel-firing combustion technology. This information allowed the preparation of a graph in which the cost of electricity was plotted as a function of cost of natural gas delivered to the generation facility. By extrapolating the data, it was possible to find the equivalence point for these other generating technologies in terms of natural gas cost on a self-consistent basis.

By comparing the average cost of natural gas delivered to electrical generating stations over a year to the average price of gas traded on the NYMEX Market over the same year, the equivalent price could be adjusted to trading prices that could be related in a consistent way to resource assessment studies. This procedure is now possible because the present generally higher price of gas makes the inherent variability in this adjustment less important than in the past. The extra cost of the capture and sequestering of carbon dioxide is assumed here to be two cents per kWeH which is added to the levelized cost of 4.2 cents/kWeH given in the report for a modern pulverized coal installation. Even with no increase in the real price of coal in the interim, an equivalence with the natural gas- based process is not reached until 2031 at a real price increase of 3% per year for liquefied natural gas (LNG) imported into North America from surplus countries by cryogenic tanker. Nevertheless, it is possible that delivered prices could increase even faster due to the difficulties and delays in providing the necessary facilities for much increased LNG shipments despite the adequacy of the resources of conventional gas around the world for many years. If not, a carbon tax or other similar financial supporting instruments will be needed to justify the provision of facilities for the capture and sequestering of carbon dioxide in coal-based generation.

November 2003
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Tel: (613) 745-6279
E-Mail: jhwalsh@ca.inter.net

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