Environmental Engineering Reference
In-Depth Information
Figure 5.4 Advanced central receiver thermal
solar power installations PS10 (left) and PS20,
near Seville, Spain. These systems of accurately
tracking mirrors (functionally similar to
Figure 5.1) image the sun onto the central
receivers, which are described as the collector at
temperature T
c
in Equation 5.3. Following the
analysis above, maximum system efficiency g
L
(mechanical power output divided by sun power
input) will occur at T
c
¼
2544 K. Achieving such
a high receiver temperature is an as yet unmet
challenge in materials science and
engineering (http://www.solarpaces.org/
Tasks/Task1/ps10.htm.).
so
P
s
ciency is 14.7%. This is a situation,
unlike that in silicon solar cells, where a large increase in ef
ciency is potentially
available. The operating ef
ciency of this plant has also been given as 18%.
In practical terms, since the suns input is available at no cost, the advantage of a
more ef
cient system is directly in the available power, which could be raised from
11MW (at 14.7% ef
ciency) to 60.7MWat 81% ef
ciency (molten lithiumheat
fluid,
assuming 300 K ambient).
To estimate the value that would come from the added 49.7MWpotential capacity,
let us assume all the power is put into the electric grid at 0.1 $/kWh. On a yearly basis,
the added revenue from the upgrade, assuming the sun power is available 0.33 of the
time, would be 0.33
¼
74.9MW. At 11MWrated capacity, the ef
10
7
10
6
$14.4 million/year.
This seems a large payoff for upgrading a portion of the system. (The land area and
the mirrors would be unchanged in this upgrade.) The reason that this was not done
may be that the technology for the (tungsten receiver/molten lithium heat
fluid)
system is not available, but one can see potential for such an advance. The design of a
turbine that will convert the high temperature into mechanical energy is also an
aspect for possible improvement.
In European Community report dated 2006 (http://ec.europa.eu/energy/res/
sectors/doc/csp/ps10_final_report.pdf.), it is stated that the total investment in PS10
is 35 million Euros, about $52.5 million. In a crude assessment, the cost per watt is
49.7MW
3.15
0.1$/3.6
¼
