Dynamical Behavior of CSP Plants

Renewable energy plant that produces electricity by means of solar irradiation. A specific of concentrated solar power is that the incoming sunlight is optically concentrated by parabolically shaped mirrors. The concentrated solar flux allows heating of a medium to temperatures of 200–1000 °C. Such high temperature medium can be stored before the heat is used in a steam power cycle to generate electricity.

A CSP system that uses line focusing concentrators in the form of parabolic troughs. The receiver is arranged in the focal line of the concentrator.

A CSP system that uses optical concentration onto a small aperture area located at the top of a tower. A large number of heliostats forms the solar field. The mirror area of each heliostat can be tracked in two axes such that the reflection of the incoming sunlight is always onto the aperture area.

The term “dynamic” describes a technical process that depends on time. The time-dependency in CSP applications is mostly determined by variations of external sources like irradiance acting on the technical system.

Technical installations used to manipulate a technical system in order to keep certain variables at their design values.

The process of modeling and simulating how a CSP plant would behave over a typical year including the given weather data information. The results are annual values of electricity production and electricity consumption that can be used for economic evaluation.

Solar thermal power plants are utility scale power production systems that work with an intermediate thermal cycle and a conventional steam turbine cycle. Whereas other entries in this book give insights into the different CSP technologies this chapter focuses on the dynamic behavior of concentrating solar power plants. The solar irradiation is a volatile source of energy that imposes variations in available energy on different time scales. The most prominent one is the daily profile of available irradiance with its peak usually in the middle of the day. The ideal daily irradiation profile is superposed by varying extinction effects in atmosphere and by short-term fluctuations induced by clouds passing over the plant. Apart from the daily profile, the available solar energy shows a typical seasonal profile with higher monthly sum in summer and lower values in winter. It is mainly those changes in solar irradiation that cause the technical system to be in a dynamic mode of operation nearly all the time. The analysis of dynamic behavior and design of appropriate control concepts has evolved into an important discipline in solar engineering. The chapter provides the reader with an overview on the relevant dynamic effects and introduces today’s state of the art. At the end of the chapter an outlook on future approaches in the field of dynamic behavior will be given.