Title: Analysis of management methods and application to maintenance of geothermal power plants

Abstract

The unit cost of geothermal energy depends on the capital investment, operations and maintenance
(O&M) costs. The capital costs are substantial but are incurred only at the inception of the power
plant and can be optimized at the inception stage. The O&M costs are incurred throughout the life
of the plant and determine the economic operation of the power plant. The greatest part of O&M
costs goes to maintenance cost. To make geothermal power plants (GPPs) economical, the maintenance
functions should be optimized by carefully selecting and planning the maintenance strategies that
will address the maintenance needs of the plant at the least cost. This research was carried out to
obtain a clear understanding of the modern management concepts and to assess their suitability to
management of maintenance in geothermal power plants. The objective of the study was to propose a
methodology that can be used to compare the management methods and determine a method that can
optimize maintenance of GPPs to make the plants operate economically.
The research involved literature review of maintenance and management methods. The maintenance
methods analysed were preventive maintenance (PM), condition based maintenance (CBM) and corrective
maintenance (CM). The management methods analysed were Six Sigma, Reliability Centered Maintenance
(RCM) and Lean method. To understand the maintenance needs of GPPs, a failure mode and effect
analysis was performed. The methods were assessed to determine their suitability in management of
maintenance of geothermal power plants. The management methods were then compared by using
analytical hierarchy process (AHP) and cost model.
The research showed that not one maintenance or management method can effectively address
maintenance needs of any system hence a combination is always desirable. It was found that the
formal management methods have been widely applied in the aviation industry, nuclear plants and
some power systems but not much is written on its application in GPPs. During informal discussions
and observation in GPPs, it was found that most of the plants applied in-house developed management
methods to model their maintenance procedures using equipment maintenance manuals for guidelines.

It is concluded that to optimize maintenance of GPPs, a suitable combination of the management
methods should be designed. RCM should be applied to design the appropriate maintenance strategies,
six sigma to address chronic problems and lean to identify and eliminate wastes. A successful
combination has great potential to optimize maintenance processes in GPPs and make the plants
economical.