CHARACTERISTICS

When efficient power plants suffer unplanned outages, less efficient plants must operate to replace that lost generation. Because these outages often occur during peak demand conditions (unlike planned outages that generally occur during off-peak periods) the efficiency differential between the plants is often large, resulting in high incremental increases in emissions, as well as greatly increased generation cost and/or decreased revenue/profits. Reducing the frequency and duration of unplanned outages has become the focus of many utilities throughout the world with outstanding success in many cases.⁷

Many techniques have been effectively utilized to achieve these improvements including: benchmarking, computerized maintenance management systems, reliability-centered maintenance, reliability modeling, outage trend analysis, plant assessments, boiler tube workstations, coal quality evaluation software, and many others. In addition, advanced project investment evaluation systems have been used to prioritize projects, helping to ensure that the most cost-effective projects are implemented first.

Advanced management methods have also been successfully implemented helping to achieve the inherent potential of each individual power plant at the least possible cost. Techniques such as condition monitoring can avoid unexpected outages and help plant management move from a reactionary to an anticipatory style, giving more control over when the plant is removed from service for repair (ideally during times when the incremental efficiency and cost difference is minimal).

SIZE:
Applicable to all unit sizes.

FEATURES:
Can involve steps to reduce both the duration of and frequency of unplanned outages.

COST:
Costs will be minimal for administrative actions, but may be substantial if purchase of computer/software tools is made. However, any actions that improve overall load management will likely be cost-effective.

CURRENT USAGE:
Emission reductions are already enjoyed as a result of improved maintenance in Ireland and South Africa as well as in the U.S.

POTENTIAL USAGE:
Benefits from increasing availability can be obtained by every utility.

ISSUES ASSOCIATED WITH IMPLEMENTING ACTION

• Most utilities have a reasonable understanding of the range of technical options available. However, a wider range of technical "best practices" options should be developed as well as methods allowing utilities to prioritize options according to their economics.
• Making improvements at existing plants will help management to more fully realize the inherent potential of advanced technologies, facilitating use of advanced, highly efficient technologies for new capacity.

CLIMATE CHANGE IMPACT

EMISSION EFFECT:
    

CONDITIONS FOR EMISSIONS MITIGATION:

• Emissions will be reduced directly because of increased efficiency of generation, and indirectly through avoiding higher emissions from operation of less-efficient units.
• This action will not produce large reductions in GHG emissions, but can be useful in achieving substantial reductions in the short-term.

EMISSION ESTIMATE:
Will vary according to the "down" and "replacement" generation sources used.

COST-EFFECTIVENESS:
Since power is dispatched using least-cost source first, any actions that reduce the downtime of least-cost, baseload power will be cost-effective. This action is highly cost-effective, enabling savings to be used for further improvements (boot-strapping).

SECONDARY EFFECTS:
If the outage avoids the emission of fossil-fuel sources, reducing the length of the outage will also reduce emissions of air pollutants. However, if replacement power comes from non-emitting sources, emissions may actually increase.

RESOURCES

• The World Energy Council and UNIPEDE jointly sponsor a Committee on Performance of Thermal Generating Plants.
• Utilities that have reduced annual unplanned availability include Southern Company, Electricity Supply Board of Ireland, and the Republic of South Africa's ESKOM. More information is available in reports published by the joint UNIPEDE/WEC Committee on Performance of Thermal Generating Plant.
• The International Quality & Productivity Center sponsors an annual conference and workshops on Shutdowns, Turnarounds, Outages & Overhauls–Best Practices in Process and Power. http://www.iqpc.com.

CONTACTS

Electric Power Research Institute
Generation Group
Palo Alto, CA
http://www.epri.com

International Quality & Productivity Center
Little Falls, NH
Tel: (973) 256-0211
Fax: (973) 256-0205
info@iqpc.com
http://www.iqpc.com

Southern Electric International, Inc.
Robert Richwine
Atlanta, GA
Tel: (770) 379-6982

Performance of Thermal Generating Plant Committee
World Energy Council
E.V. Nekhaev
London, UK