Page 25 - Design of Solar Thermal Power Plants

18 1. INTRODUCTION

3. Power dispatching. CSP generation can also serve as a power-
dispatching source for the power grid like a pumped-storage
power plant; under a considerable peakevalley price mechanism, it
will generate greater economic benefits. This also accelerates the cost
payback period of the power plant.
4. During the energy conversion process, photovoltaic power
generation only requires one opticalepower conversion, whereas
CSP power generation requires the secondary conversion of optical
to thermal to power. Although this has increased the difficulty of
system integration, thermal production as the intermediate link of
CSP plant operation has also expanded the application scope of CSP
power-generation techniques. For example, the superheated steam
produced in CSP generation can be used for combined power
generation with conventional coal, gas, and biomass power plants.
Furthermore, the thermal energy produced by CSP generation can
be deemed a by-product for use in seawater desalinization,
industrial thermal and air-conditioning, etc.
5. Raw material supply. Photovoltaic power generation mainly
consists of photovoltaic solar panels. Currently, those that have
been widely applied are crystalline silicon cells and CdTe thin-film
cells, the raw material supplies of which could be tight. Market
prices could rise, especially for those elements of CdTe cells that use
rare metals that are subject to triggering large price fluctuations.
Raw materials of the CSP power plant, on the other hand, are mainly
commodity items such as glass, steel, concrete, and other common
materials in sufficient supply; major price fluctuations in these raw
material supplies are unlikely.

1.2.2 Main Technical Forms of Solar Thermal Power
Generation

1.2.2.1 Solar Tower Power Generation
Solar tower power generation (Fig. 1.8) is a system that transmits solar
irradiation to the receiver mounted on the tower and acquires the high-
temperature heat transfer medium through multiple heliostats by
tracking movement of the sun, generating power directly or indirectly
through the thermal cycle using a high-temperature heat transfer
liquid [6]. Solar tower power plants mainly include a heliostat, a receiver
tower, a receiver, thermal storage, and a generator unit. Under the
working state of the solar tower thermal power plant, all heliostats in
the concentration field reflect daylight through double-axis tracking of the
azimuthal angle and altitude angle to the receiver mounted on the solar
tower in order to thermal the heat transfer fluid inside the receiver of