Page 53 - Design of Solar Thermal Power Plants

46 1. INTRODUCTION

FIGURE 1.31 Ivanpah tower power plant under commissioning (September, 2013).

Decreased efficiency of Solar Two in the United States is caused by
the heliostat being located too far from the receiver tower after the
area of the concentration field was enlarged, sometimes even to
the south of the tower with an extremely low optical efficiency. Thus
the efficiency of the concentration field is low. Furthermore, if the
large-scale heliostat concentration field is poorly designed, the
spillage loss of the receiver might be great, which results in a
decrease in the efficiency of the collector field. Special attention
should be paid to this when designing a large-scale tower power
plant. The Ivanpah tower plant is under commissioning (Fig. 1.31)
with a total capacity of 392 MW; it consists of three receiver towers,
with each receiver tower corresponding to a capacity above 130 MW.
5. Energy storage utilization factor. This is the percentage of available
thermal energy to the total thermal storage capacity in the energy
storage system.
6. Solar multiple. Ratio of the net thermal power of the solar field at the
design point to the thermal power required from the solar field to run
the power block at rated power, which reflects differences between
thermal collection system capacity and power generation system
capacity. This parameter at a specific design point can be used to
define the rated capacity of the steam turbine and thermal storage.