Cost-effective maintenance for the new millennium

As we move into the new Millennium, commercial pressures deriving from deregulation and privatisation of the electricity supply industry are providing renewed impetus to reducing unit price to consumers by examining and minimising all controllable costs in both the production and supply. Reducing power generation plant maintenance expenditure offers an obvious opportunity to compete more effectively. However, depending on the local generating capacity/demand situation, improving plant availability may offer substantially higher rewards. The challenge is to target and minimise maintenance expenditure in order to achieve (only) the required level of plant availability without compromising personnel safety. Inspection and maintenance programmes defined on the basis of a systematic risk assessment, focus expenditure to components where it will be most effective in reducing failure outages, thereby offering the opportunity to reduce unplanned unavailability. Planned unavailability can also be reduced either by shortening plant overhauls as a result of risk-focused maintenance or by using the risk assessment as the basis for extending the interval between plant inspections. The risk profile for different inspection/maintenance strategies and the associated costs can be compared to determine the optimum strategy for the particular generating environment. This paper illustrates a practical approach that has been adopted to plan plant inspection programmes on a risk basis. Two applications are described. The first demonstrates the approach in a situation where increased plant availability was the goal. The second describes the use of risk-based inspection planning to provide the foundation for a successful application to increase the interval between statutory inspections of boilers.