Optimization of Gas Turbines Maintenance Contracts for Power Plants Long-Term Competitiveness

摘要

The fact that modern-day gas turbines are operated at high firing temperatures makes them the technology when used in a combined cycle that delivers the highest efficiency among the fossil-fuel power plants, with 60%+ net efficiency capabilities being a reality. Gas turbines are also proving to be the fossil-fuel technology of choice when it comes to operational flexibility, with abilities of high cycling and peaking, fast startups and load ramps. High firing temperatures and operational flexibility are however also the reason for relatively intense service costs of gas turbines compared to other fossil-fuel technologies. GT service aspects, being an important element in the overall cost of electricity equation for gas-fired power plants, have been continuously analyzed and optimized by the power plant operators as well as the original engine manufacturers (OEM’s) and independent service providers (ISP’s). The proliferation of independent service providers to a certain degree has opened up the competition in this particular field, resulting in continuous lowering of the service costs as well as improvements in the quality of after-sales services. At the same time, many different maintenance contract models have been developed in order to suit specific customers’ needs, operating regimes and technology class. For the latest most-advanced gas turbine technologies on the market the power companies typically prefer to enter in to some form of long-term service agreement with the original engine manufacturer which covers engine outages as well as supervisory support on the operations-side, and typically including commercial performance guarantees pertaining to availability, degradation and the like. On the other hand, for more mature well proven GT technologies, experienced owners may alternatively prefer a more flexible approach and purchase or repair spare parts and services as and when needed, either from the OEM or independent service providers. This paper analyzes advantages and disadvantages of various GT service models and their long term impact on power plant competitiveness from the power plants operators’ perspective, based on several case studies and recent maintenance technology trends.