Reducing the Number of Turbine Starts in Concentrating Solar Power Plants Through the Integration of Thermal Energy Storage

Abstract

The operation of steam turbine units in solar thermal power plants is very different than in conventional baseload plants. Due to the variability of the solar resource, much higher frequencies of plant startups are encountered. This study provides an insight to the influence of thermal energy storage (TES) integration on the typical cycling operation of solar thermal power plants. It is demonstrated that the integration of storage leads to significant reductions in the annual number of turbine starts and is thus beneficial to the turbine lifetime. At the same time, the effects of storage integration on the electricity costs are analyzed to ensure that the designs remain economically competitive. Large storage capacities, can allow the plant to be shifted from a daily starting regime to one where less than 20 plant starts occur annually. Additionally, the concept of equivalent operating hours (EOHs) is used to further analyze the direct impact of storage integration on the maintenance planning of the turbine units.