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Table of Contents

PPRG Contents

Major Topic Sections

Fossil-fueled Power
Non-Fossil Generation
End-Use Efficiency
Electricity T&D
Carbon Sequestration
Non-CO2 Reductions
Other GHG Reductions

Related topics in this section

Up to Section Head
Advanced Coal Power
Turbine Efficiency
Cogeneration & CHP
Natural Gas
Upgrading Controls
Plant Equip. Upgrades
Coal Prep & Handling


 Repowering Older Plants


As power plants age, the efficiency of steam production equipment declines and/or the equipment becomes technologically obsolete, even with regular maintenance. Rather than replace aging steam production equipment in kind, some utilities have chosen to replace it with new technology. This process is called "repowering" and offers the opportunity to increase the efficiency of the process through the installation of new, improved equipment. Repowering with more efficient equipment can reduce net emissions of greenhouse gases and air pollutants compared to operating the original equipment. Repowering with equipment that uses lower-carbon fuels can further reduce net greenhouse gas emissions.

Repowering can take several forms. It can involve the replacement of the boiler with a new steam-producing facility, or it can involve a totally new steam production process involving a combustion turbine and heat steam generator and additional generating equipment.

Repowering with a natural gas-fired combustion turbine and adding a heat recovery steam generator improves overall efficiency, and often increases the electrical output of the facility. Greenhouse gas emissions could be reduced as natural gas is lower in carbon than the fuel previously used. Repowering with a combustion turbine also has environmental benefits of more effective control of SO2, NOx, and particulate emissions.

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 References, Sources, and Other Useful Data

Electric Power Research Institute, “SOAPP-REPO 3.0: SOAPP-REPO Combined-Cycle Repowering Workstation" (Software  product, Version 3.0, May 2005)

The State-of-the-Art Power Plant Repowering Products (SOAPP-REPO) WorkStation version 3.0 is a software application that integrates process design, costing, and financial analysis for combined-cycle repowering of existing fossil steam plants, enabling users to quickly assess the viability of a repowering scenario on a site-specific basis. The SOAPP-REPO 3.0 application includes a re-use plan for the steam turbines, feedwater heaters, and balance-of-plant equipment and critical data inputs for the existing steam cycle and re-used equipment.

Electric Power Research Institute, “Repowering Existing Fossil Steam Plants”

Repowering evaluation methodology typically used in the United States, technology options, and the SOAPP repowering software now available to facilitate evaluations are reviewed in this paper.

Federation of Electric Companies of Japan, "Green Handbook Peer Review: Instructions for the Operation & Maintenance Technologies and Efficiency Improvements for the Coal fired Power Plants", (April 2007)

This textbook has been prepared by Japanese electric power companies as a contribution to “PGT-06-01: Best Practices for Power Generation” one of the activities undertaken by the ‘Power Generation and Power Distribution Task Force’ in the context of the ASIA-PACIFIC PARTNERSHIP on Clean Development and Climate. The textbook describes important issues associated with maintaining, and enhancing, levels of heat efficiency at a coal-fired thermal power plants, and constitutes a summary of matters of which all technicians working in power generation plants need to be aware. The 482 pages in this manual cover in depth the best practices for thermal power plants for functional and operational control, maintenance and efficiency control, and environmental preservation.

Siemens Power Generation, “Repowering”

The gas turbine (GT) in conjunction with a heat recovery steam generator (HRSG) and a steam turbine (ST), makes combined cycle power plants (CCPP) to the most efficient power generation facilities. Existing direct fired plants can utilize this advanced cycle concept by adding a GT and a HRSG. This so called repowering scheme makes the existing power generation facility equally efficient as modern combined cycle power plant. There are several alternatives to combine and integrate a gas turbine into an existing steam power plant. A detailed assessment of the existing plant equipment as well as technical and economic boundary conditions of a specific project determines the optimal approach and the selection of the repowering concept.

U.S. Department of Energy, National Energy Technology Laboratory, “Clean Coal Technology Compendium”

The Clean Coal Technology Compendium is a comprehensive repository of information generated through the Department of Energy's major clean coal demonstration programs. The information is organized by program: Clean Coal Power Initiative (CCPI), Power Plant Improvement Initiative (PPII), or Clean Coal Technology Demonstration Program (CCTDP).

U.S. Department of Energy, National Energy Technology Laboratory, “Combustion - Fluidized-Bed Combustion Repower: FBC Repowering Project Overview”

This is the overview page for discussions of the projects in CHIPPS, PFBC, GFBCC, and APFBC repowering series.  These projects detail how existing power plants can be improved using advanced combustion technologies.  The present PFBC, GFBCC, and APFBC repowering efforts are described in a series of 14 volumes.

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Last revised: Dec. 11, 2009.