This Topical Report presents the results of Task 4 of the Westinghouse ATS Program. The purpose of Task 4 is to determine the technical development needs for conversion of the gas-fired ATS (GFATS). Two closely related, advanced, coal-based power plant technologies have been selected for consideration as the CFATS -- air-blown, coal gasification with hot gas cleaning incorporated into an Integrated Gasification Combined Cycle (IGCC), and the Second-Generation Pressurized Fluidized Bed Combustion (PFBC) combined cycle. These are described and their estimated performance and emissions in the CFATS are reported. A development program for the CFATS is described that focuses on major commercialization issues. These issues are in the areas of combustion, flow distribution, structural analysis, and materials selection.