Programm Photovoltaik Ausgabe 2008 ... - Bundesamt für Energie BFE

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Type of
meas.
Direct with
c-Si ref cell
Multiflash
Direct with
filtered c-Si
ref cell
MODULE
Cell Type
(P0-Pa)/Pa
(%)
(P3-Pa)/Pa
(%)
(P15-P3)/P3
(%)
(P15-Pa)/Pa
(%)
Miitsubishi PV-MF130EA2LF mc-Si -2.2% -0.3% -0.6% -0.8%
Suntech STP150-24 mc-Si -1.2% -0.6% -1.0% -1.6%
Kyocera KC125GHT-2 mc-Si -1.6% -1.1% -1.1% -2.2%
RWE ASE-165-GT-FT mc-Si -2.7% -2.7% -1.4% -4.1%
Solarwatt MHHplus220 mc-Si -2.9% -4.1% -0.5% -4.6%
IBC-215S Megaline mc-Si 0.6% 0.4% -0.7% -0.3%
Solar World SW165 mc-Si -0.1% -0.4% -1.7% -2.1%
BP Solar BP7180 sc-Si -1.6% -1.3% -1.3% -2.6%
Sharp NT-175E1 sc-Si -1.0% -0.1% -1.5% -1.6%
Sanyo HIP180NE1 HIT 0.3% -0.3% -2.0% -2.2%
Sunpower STM210 F sc-Si 0.2% -1.0% -1.4% -2.3%
First Solar FS-60 CdTe NaN -1.9% NaN
Kaneka K60 a-Si -27.2% -8.7% -33.5%
UniSolar ES-62T a-Si -11.1% -4.7% -15.3%
Table 2: initial power degradation {(P0-Pa)/Pa}, first 3 and 15 months and last year degradation.
abbrev.
3.2.5 Initial degradation
Initial degradation in power {(P0-Pa)/Pa} of the c-Si modules (see Table 2) is on average – 1.1%,
ranging from +0.6% to -2.9%. The values in the ± 1 % bracket are within the tolerance interval for
measurement repeatability.
The performance loss is mainly due to degradation of the short circuit current Isc. Considering the
measurement precision, for degradations up to -5% a linear relation between power and Isc degradation
can be observed. In the BP7180 module, however, initial degradation occurred mainly in voltage
(dPm: -1.6%; dIsc: -0.8%; dVoc: -1.3%).
Initial power degradation {(P3-Pa)/Pa} of the a-Si K60 module was -27.2%, while degradation in the
ES-62T module was only -11.1%. (Table 2)
3.2.6 Power degradation after 1 year of exposure
In the standard modules with c-Si cells, the average reduction after one year of exposure (from P3 to
P15) in most cases was very low, ranging from -0.5% and -2.0%, and four of them are within the reproducibility
error limits of the measurements using the flash sun simulator.
3.2.7 Annual energy performance
For the evaluation of the energy output, our institute differentiates between two points of view. The first
is more consumer oriented (3.2.8), as it looks at the energy output in relation to Pn and the second
one (3.2.9) is a purely technological inter-comparison, where the real stabilized STC power is used as
reference.
For all figures the energy output in kWh/kWp refers to the best one of the test cycle. For reasons of
simplicity the average of the two modules is shown here. The grey bars correspond to the respective
difference between the two modules. To show the range of order of the kWh/kWp, uncertainty error
bars were added in Figure 2 and Figure 3. In the case of name plate power as reference, the uncertainty
is on the one hand due to the energy measurement itself (±1.0%) and on the other hand due to
the uncertainty in power declarations (±tp%). Taking instead the real power as reference, the uncertainty
is the sum of the energy measurement uncertainty (±1.0%) and the ISAAC-TISO power measurement
accuracy (±2% for c-Si, not defined for all thin-film technologies - CdTe and a-Si). The ±1.0%
of the outdoor measurement uncertainty includes the data acquisition accuracy, MPPT tracking efficiency,
cable connections, differences in albedo and ventilation, and module alignment errors. All a-Si
error bars are to be assessed with care due to the non availability of the exact error in indoor performance
determination.
The single junction a-Si technologies of K60 (ave. PR 0.88) shows a very strong initial degradation
which is dominating respect to the seasonal variations. Being not totally concluded the initial degradation
an inter-comparison with the other modules is almost impossible.
3.2.8 Annual energy performance comparison with Pn as reference
Due to the above-mentioned reasons and the different degradations occurring during the first year of
exposure, the kWh ranking with respect to nominal power Pn (Figure 2) leads to slightly different figures
compared to the one referring to the measured power P3 (Figure 3).
Centrale di test ISAAC-TISO, D. Chianese, ISAAC-TISO Seite 163 von 288
MF
STP
KC
ASE
MHH
IBC
SW
BP
NT
HIP
STM
FS
K
ES