Oxyfuel economics for low-, mid-, and high-sulfur coals

摘要

In previous work[1], we summarized cost and performance for Oxyfuel retrofit to PC boilers of various sizes for several coal types. In that work, incremental capital costs associated with the retrofit were amortized and added to operating and fuel cost to obtain the total annual costs and implied electricity cost for the resulting low-CO_2 plant. For comparison with other CO_2 capture strategies, we calculated a simple cost per ton of CO_2 avoided as the quotient of increased cost over the base case (without retrofit) and the amount of CO_2 avoided. We summarize that work here and extend it, recognizing that the broad deployment of Oxyfuel retrofit will result in a capacity reduction of 30 to 35%. That reduction must be made up, either by increased utilization of existing capacity or by construction of new capacity; either option adds to the total cost of the CO_2 reductions achieved. Moreover, most new capacity options will produce some CO_2, reducing the net CO_2 emission reduction benefit to be credited to the original retrofit. We describe a simple procedure to account for these changes in the net benefit calculation and demonstrate the usefulness of assigning a CO_2 emission metric to electricity produced by various sources.