The role of Life Cycle Engineering in hydropower plants from the viewpoint of modernization and upgrading is getting a more important status in the 21st century. Many hydropower plants were built from the 1950s through 1980s and although in most of the cases a proper maintenance has been performed, the aging process cannot be fully eliminated which makes at least rehabilitation necessary. From the main phases in the life cycle of a hydropower plant as shown in Fig. 1 the three phases Operation, Maintenance and Optimization are of major interest for further investigations and assessment. They are the most affected phases during the life time in relation to the age and the changing environment of a hydropower plant.
During the last decade the operating of a hydropower station has passed through basic changes mainly driven by new market conditions. The increasing demand of grid services, i.e. regulating energy, availability for grid stabilization and prevention of black-outs, can result in a change of operating conditions, increased number of start/stops or load rejections which have direct influence on the residual life of relevant components and must be considered in a possible modernization or upgrading scenario.
Maintenance strategies of hydropower plants can differ in a wide range, depending on many factors such as size and type of the units, environmental and operating issues. Whereas, the predictive (or preventive) concept is in a favour compared to the corrective (or reactive) concept. It is essential for a modernization or upgrading project to know about this concept type and the related inspection periods or repairs which have been carried out during the past of the hydropower plant in order to gather information about the reliability and availability of the existing equipment in a hydropower plant.
In the optimization phase of a hydropower plant’s life cycle, questions about the feasible modernization scenario may arise. There can be on the one side pure rehabilitation with the goal of life extension and restoration of the original performance levels, or, on the other side modernization including an increase of output and replacement of major parts with modern and more efficient design. Independent of the chosen scenario, the result of a rehabilitation or upgrading measure should achieve the optimum energy production improvement combined with a restoration of the safety level and the extension of the residual life of individual components.
For modernization and upgrading projects of hydropower plants, the life cycle engineering is focused on three main phases – operation, maintenance and optimization – which should be carefully studied in advance to gain the maximum benefit in all aspects, technological, economical and ecological. Thus, modernization and/or upgrading can efficiently contribute to the sustainable use of water resources.