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Results of the APolloN PRoject ANd coNceNtRAtiNg PhotovoltAic PeRsPective

Fixed PV, Tracked PV and HCPV: Energy Generation Comparison

What are the barriers to overcome in order to make HCPV competitive? An attempt to answer this question
is made by comparing three types of installations, frst of all, from the energetic point of view and then from the
economic point of view. The comparison between fxed conventional c-Si-PV, 2-axis tracked c-Si and HCPV presented
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below is based on theoretical simulations using PVSYST-software .
Three sites have been considered for the analyses: Ragusa (Sicily, Italy), Giza (Egypt) and Tucson (Arizona, USA).
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Ragusa is one of the best sites in Italy but its DNI is 10%, that is to say less than the 6 kWh/m /day limit indicated for
HCPV target areas. Giza has a DNI slightly above this level but the amount of diffuse light is relatively high. Tucson
has the highest DNI and is in a desert-area with very little diffuse light (Table 14).

tABLE 14. Irradiation and temperature levels in the three sites chosen for the comparison of different PV-
technologies

Sites chosen Ragusa, giza, tucson,
for analyses Italy latitude 36.9 Egypt latitude 30.0 USA latitude 32.2 Note
Average yearly 18.7 21.1 20.3
temperature [°C] (from PVGIS) (from NASA) (from NASA)
Global Horizontal (GHO)
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[kWh/m /year] 1795 2165 1976
Global Opt. Inclined 1973 2342 222 exploited by
(Ginc) [kWh/m /year] (GHO + 9.9%) (GHO +8.2%) (GHO +12.6%) fxed c-Si
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Global Normal 2729 3220 3163 exploited
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(GNI) [kWh/m /year] (GHO +52.0%) (GHO+48.7%) (GHO +60.1%) by tracked c-Si
Direct Normal (DNI) 1971 2274 2501 exploited
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[kWh/m /year)] (GNI-27.8%) (GNI-29.4%) (GNI-20.9) by HCPV
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[kWh/m /day] 5.4 6.2 6.9
DNI/Ginc 99.90% 97.10% 112.40% relevant
for fxed
c-Si vs. HCPV

The simulation is performed for a fxed-size terrain of 100x200 m with the long side parallel to the North-South
direction. For the fxed c-Si there is a single layout with 5x29 supports (Figure 88, F). For the tracked solutions two
layouts have been simulated: a dense one with 91 trackers (Figure 88, T1) and a sparse one with 55 trackers (Figure
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88, T2). Each tracker has a panel of 6x12 m .
Table 15 provides data on the terrain layout and on the installed power.
The c-Si modules used in the simulation are commercially existing 260 Wp modules with a declared STC-
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effciency of 15.2% (on net cell area @Ginc=1,000 W/m ; 13.4% on gross module area). Characteristics have been
taken from the PVSYST database and from supplier datasheets. The PVSYST recommended optimal tilt is used. The
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distance between rows is such to have no shading on December 21 at noon.
Three types of HCPV modules have been considered with respectively 30, 32 and 34% CSTC-effciency (on net
area @DNI=1,000 W/m ). The 30% module could be representative of the off-axis mirror-based module developed in
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the APOLLON project.

FiguRE 88. Terrain layouts used for simulation in PVSyST. F: fxed c-Si with 5x29 support structures and a total
of 5,220 modules organized in 290 strings; T1: dense layout with 91 trackers carrying 3,276 c-Si modules or 7,280
HCPV-modules; T2: sparse layout with 55 trackers carrying 1,980 c-Si modules or 4,400 HCPV-modules

F t1 t2

48 www.pvsyst.com/en/.

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