Page 16 - Design of Solar Thermal Power Plants

1.2 BRIEF INTRODUCTION TO SOLAR THERMAL POWER GENERATION 9

and surface slope 3%dapproximates 16,000 GW, which is similar to
that of the United States; the potential capacity to be installed with a
2
direct normal irradiation of not less than 7 kWh/(m day) approximates
1400 GW. In terms of annual power generation capacity, China’s poten-
tial annual CSP generation capacity is 42,000 TWh/year, which means
that even if all fossil fuel energy resources become exhausted, China will
still enjoy abundant CSP generation resources far beyond those required
for self-sufficiency.
China has abundant solar energy resources. Its annual solar irradiation
2
falls approximately in the range of 1050e2450 kWh/m ; on average, the
solar energy that irradiates the 9.6 million square kilometers of land in
China every year is equivalent to 1700 billion tons of standard coal. About
300,000 square kilometers of the Gobi Desert in China, which accounts for
about 23% of China’s total desert area, can be used to develop solar power
generation. Based on existing CSP generation technologies and annual
conversion efficiency, constructing power plants on China’s 70,000 square
kilometers of sand would result in annual power generation that would
satisfy power demands of China equal to those for all of 2018. China’s
extremely abundant solar and sand resources are especially prevalent
western China, where CSP technologies will play a significant role in
economic development, environmental protection, and resource protec-
tion. As constantly supported by the 8th, 10th, 11th, and 12th Five-Year
Plans of China on science and technology issued by the Ministry of
Science and Technology of the People’s Republic of China, numerous
achievements have been made on parabolic trough, solar tower, and
parabolic dish CSP generation systems. In July 2011, the Beijing Badaling
megawatt-level solar tower power plant was completed and started to
produce steam [3]; it started generating power in August 2012. The power
plant can generate power not only by pure solar energy, but also by being
connected with fossil fuels in a parallel manner. The Chinese first para-
bolic trough solar power plant was completed in the Yanqing district of
Beijing in 2017.
CSP generation is capable of applying two thermal cycles, namely
direct and indirect (double-loop). The former directly drives the steam
turbine unit for power generation (Fig. 1.1) by using the steam produced
by the receiver. The latter produces steam thermally using the working
media-water or fluid with a low boiling point in the auxiliary system
through thermal exchange during the thermal cycle of the main system
and thus driving the steam turbine unit for power generation (Fig. 1.2).
Compared with a conventional thermal power plant, the most intuitive
difference between the two is that the conventional boiler is replaced with
thermal collection and storage facilities in CSP generation, whereas the
thermal cycle mode and respective equipment applied for thermalework-
power conversion are basically the same as those used in conventional
power plants. In comparing an CSP power plant’s acquisition mode with