Solar Thermal Power Plants - Renewable Energy: Technology, Economics and Environment - page 227

75 US$/m 2 /5-37/. For the overall plant, in total, specific investment costs of ap-
proximately 2,000 €/kW are assumed (Table 5.18).
Table 5.17 Parameters of the assessed solar pond

Nominal capacity 5 MW a (peak capacity)
Collector surface 250,000 m 2
Heat exchanger external; the brine is pumped from the pond and recycled to the
pond in cooled condition
Full-load hours 1,150 h/a
Storage deepest water layer of the pond serves as thermal storage
Solar share 100 %
Net efficiency b 1 %
a The average capacity amounts to approximately 650 kW; at short-term higher capaci-
ties are possible so that higher revenues can be achieved (peak-load power); b effi-
ciency between incident solar radiation and produced electric energy.

Operation costs. For this purpose, operation costs are estimated at a lump-sum of
1 % of the investment costs. Besides the maintenance of the heat exchangers and
the ORC plant further measures are required since the salt that diffuses from the
bottom to the surface has to be retrieved. Compared to conventional steam power
plants, the required water quantity is thus many times higher.
Table 5.18 Estimation of the power generation costs of a 5 MW solar pond provided with
external heat exchanger

Specific investment costs 2,000 €/kW

Operation costs 100,000 €/a

Power generation costs 0.14 €/kWh

Electricity generation costs. According to Table 5.18, the power generation costs
for a solar pond of a surface of 250,000 m 2 and annual operation costs of ap-
proximately 100,000 €, amount to approximately 0.14 €/kWh. However, it has
been assumed that brine or appropriate salt are available at the site free of charge,
so that only transportation measures are required.
For an economic assessment within the scope of operational optimisation, it
also has to be considered that electric capacity must be available at any time of the
day. Solar ponds can thus generally also serve as peak-load power stations.

Environmental analysis. The environmental effects of solar pond power plants
are largely similar to those of solar tower power plants; they are thus discussed in
Chapter 5.2.2 on solar tower power plants. Additionally, the salt brine might cause
environmental effects when polluting the surroundings of a solar pond. Also, the
use of fresh water during the operation of such plants might be considerable. In
areas with a shortage of water this could lead to environmental effects.