Environmental Engineering Reference
In-Depth Information
Water can thus be withdrawn from the storage zone at the bottom at an ap-
proximate temperature of 80 to 90 °C. This heat can subsequently be used for
power generation by an ORC process.
Solar pond power plants of electric capacities from a few ten kW up to a few
MW have been built in Israel, the US (Texas), Australia and India (for process
heat provision /5-34/), among other countries. With approximately one percent,
solar thermal efficiencies are low; the mean specific capacities range from 5 to
10 W/m
2
depending on radiation, salt content and maximum temperature. For the
short-term, also higher capacities can be withdrawn; however, in such a case the
solar pond would cool down much faster. Table 5.16 shows typical examples (see
also /5-35/, /5-36/, /5-37/).
Table 5.16
Data of selected solar pond power plants
El Paso
Texas, USA
Beit Ha'Arava
Israel
Pyramid Hill
Australia
Capacity
300 kW
th
70 kW
el
5 MW
el
max.
570 kW
el
(average)
60 kW
th
3,350 m
2
250,000 m
2
3,000 m
2
Pond surface
5.6.2
Economic and environmental analysis
The following explanations are aimed at assessing solar pond power plants ac-
cording to economic and environmental parameters.
Economic analysis.
In line with the preceding assessment method, in the follow-
ing, the power generation costs are calculated for solar pond power plants. Ac-
cording to this, the costs for construction and operation are determined and as-
sessed in the form of annuities. On this basis and the produced electrical energy,
the power generation costs are calculated. For this purpose, a technical lifetime of
25 years and an interest rate of 4.5 % have been assumed.
Since such plants are only installed in areas with a high share of solar radiation,
a reference site has been assumed which is characterised by an annual total global
radiation on the horizontal axis of 2,300 kWh/m
2
.
Table 5.17 outlines the main parameters of the assessed solar pond. The solar
pond power plant investigated here has a capacity of 5 MW.
Investment costs.
Since there are only a few solar ponds, all of them being unique,
there are virtually no market prices available that could serve as a basis for these
analyses. This is why the following cost estimations have been based on literature
values. For this purpose, specific investment costs of 40 €/m
2
of pond surface
have been assumed. Literature values are based on cost estimations for civil engi-
neering works and geomembranes; other sources indicate values between 15 and
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