plants today employ subcritical steam conditions, which give lower efficiency (typically 36 to 37 percent). Some early supercritical units, however, are still operating satisfactorily. The most efficient supercritical steam unit operating in the United States is the Marshall 4 unit of Duke Power, which was installed in 1970 with a design efficiency of 40 percent and today operates at a 38 percent efficiency without a FGD (flue gas desulfurization) unit (Electric Light and Power, 1993). Typical capital costs of modern U.S. subcritical pulverized coal plants equipped with an FGD system range from about $1,100 to $1,500/kW, with typical electricity costs of about 40 to 55 mills/kWh. 1

Current Programs

The DOE program to improve pulverized coal-based power generation systems builds on several aspects of current pulverized coal power generation technology that are commercial or near-commercial, including:

  • staged air and other combustion modification techniques for NOx control;
  • selective noncatalytic NOx reduction using ammonia or amines;
  • advanced (supercritical) steam conditions to 590 °C (1100 °F), 31 MPa (4,500 psia);
  • combined power generation and space heating (hot water);
  • combined power generation and process steam (cogeneration);
  • coal-water slurry combustion with up to 70 percent coal by weight; and
  • expansion turbine electricity generation using steam, hot combustion gases, or heated air.

As shown in Table 7-1, there are three major components of the DOE RD&D (research, development, and demonstration) program on pulverized coal-based power generation systems: the APC (advanced pulverized coal) systems activity incorporating the LEBS (low-emission boiler system) program and the coal-fired cogeneration program; the IFC (indirectly fired cycle) system activity comprising the externally fired combined-cycle (EFCC) and HIPPS (high-performance power system) programs; and the direct coal-fired heat engines systems activity, incorporating two distinct but related power generation systems—direct coal-fired gas turbines and direct coal-fired diesels. The major technology goals for these programs are summarized in Table 7-1. The FY 1994 budgets for these activities were $9.1 million for advanced pulverized coal and $14.4 million for IFCs.

Advanced Pulverized Coal

The LEBS program is focused on improvement in currently available pulverized coal systems through integration with advanced combustion and emissions

1  

Personal communication from C. McGowin, Electric Power Research Institute, to E.S. Rubin, Vice Chair, Committee on Strategic Assessment of DOE's Coal Program, May 1994.



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