Page 35 - Design of Solar Thermal Power Plants

28 1. INTRODUCTION

TABLE 1.4 Comparative Performance of Three Concentrating Solar Thermal Power
Generation Systems
Performance Parameters Parabolic Trough Solar Tower Dish-Stirling
Installed capacity 50e600 MW 10e600 MW 5e25 kW
Working temperature of 400 565e1200 750

receiver/ C
Maximum efficiency/% 20 23 30
Annual mean 12e16 16e20 12e25
efficiency/%
Commercialization Rich Yes No
experiences
Thermal storage Yes Yes No
conditions
Power of fossil fuel hybrid Yes Yes Yes
thermal source
Potential of No Yes Yes
BraytoneRankine
combined cycle
Future mean power 6 6 10
generation cost (levelized
electricity cost), US¢/(kWh)

1.2.3 Basic Terms

This section describes the basic concepts of CSP generation that are
frequently used, which will be helpful in providing designers with clear
knowledge of these concepts.
Firstly, “design point.” “Design point” is an important yet hard-to-
understand concept associated with CSP plant design. There is no design
point in the conventional thermal power and photovoltaic power
systems.
The design point is used in a solar power generation system to deter-
mine the parameters of the solar thermal collection and power generation
systems, including year, day, hour as well as the corresponding weather
conditions and solar direct normal irradiance.
The design point is associated with a specific hour and corresponding
solar irradiance and ambient air temperature. It can be used to clarify the
area of concentration field, capacity of the steam turbine generator, ca-
pacity of thermal storage on a quantitative basis, and relationship among
these crucial factors. Normally, a design point is not defined based on
peak value and extreme solar angle under local weather conditions, and
wind speed is not considered. For a large-scale power plant with a