solar power analysed
DESCRIPTION
A small residential PV-system of 1.5 kWp is analysed for yield and failures after running during 5 years: Easy to understand example on terms such as specific yield, annual yield, irradiation and solarPV electricity. Typical 'camel back' curves stand for high summer yields and low to nothing in winter.TRANSCRIPT
Solar power analysedA close lock into 5 years of operation of a small
residential PV-system !!!!!!!!
brought to you by goMicromorph PV-School
Energy Yield of a PV-systemEn
ergy
(kW
h)
0
400
800
1200
1600
2000
2008 2009 2010 2011 2012 2013
Average Annual Energy Annual Energy (kWh)
1'6531'644
1'878
1'4791'6031'564
Annual specific yield
Ener
gy (k
Wh)
0
400
800
1200
1600
2000
2008 2009 2010 2011 2012 2013
Average Annual EnergyAnnual Energy (kWh)
1'6531'6441'878
1'4791'6031'564
Formula 1:!Specific Yield = energy yield / nominal solar power !Example:!A PV-system of 1.5 kWPeak installed power (6 modules à 250 W) generates in a good year 1800 kWh of electricity. a) calculate the annual specific yield. b) calculate the average monthly specific
yield. Solutions: a) Ya = 1800 kWh / 1.5 kWp
Ya = 1200 kWh/kWp = 1200 h/a b) Ym = Ya / 12 = 100 h/m
The most meaningful figure of a solarPV system is the specific yield, indicating the energy per installed power - or the number of full operation hours per year or per month.
Annual specific yield
Ener
gy (k
Wh)
0
400
800
1200
1600
2000
2008 2009 2010 2011 2012 2013
Average Annual EnergyAnnual Energy (kWh)
1'6531'6441'878
1'4791'6031'564
Nominal PV power: Pg = 1.5 kWPeak Installed: 2007 Thin-film silicon (aSi) modules, new micromorph modules installed 2012 New nominal power: Pg = 2 kWPeak
Specific Yield (kWh/kWp)Ya 1043 1069 986 1252 1096 827
Pg! 1.5 1.5 1.5 1.5 1.5 2.0
Monthly energy yieldsSp
ecifi
c Yi
eld
(kW
h/kW
p)
0
45
90
135
180
1 2 3 4 5 6 7 8 9 10 11 12
Spec.Yield 2010 Spec.Yield 2011 Spec.Yield 2012 Spec.Yield 2013 Average Spec.Yield 2009
Monthly energy yieldsSp
ecifi
c Yi
eld
(kW
h/kW
p)
0
45
90
135
180
1 2 3 4 5 6 7 8 9 10 11 12
Spec.Yield 2010 Spec.Yield 2011 Spec.Yield 2012Spec.Yield 2013 Average Spec.Yield 2009
0
45
90
135
180
1 2 3 4 5 6 7 8 9 10 11 12
Average
Average yieldsSp
ecifi
c Yi
eld
(kW
h/kW
p)
0
45
90
135
180
1 2 3 4 5 6 7 8 9 10 11 12
Spec.Yield 2010 Spec.Yield 2011 Spec.Yield 2012Spec.Yield 2013 Average Spec.Yield 2009
Monthly values16 19 82 131 149 146 156 148 118 76 36 4 Average19 25 49 28 28 13 7 13 15 13 19 4 Std. Dev
119% 135% 60% 21% 19% 9% 5% 9% 13% 17% 52% 97% Std. Dev %
Ener
gy (k
Wh)
0
400
800
1200
1600
2000
2008 2009 2010 2011 2012 2013
Average Annual EnergyAnnual Energy (kWh)
1'6531'6441'878
1'4791'6031'564
Yearly values1637 kWh/kWp134 kWh/kWp8% %
Large variations on monthly basis, less variation from year-to-year comparison.
Monthly energy yields
0
100
Sum
(Max
(Ene
rgy/
Wpea
k (W
h/W
)))
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
2 3 4 5 6 7 8 9 10 11 12
Year within Month
Year 2008 2009 2010 2011 2012 2013
Energy (kWh/kWp)
Monthly irradiation
0
100000
200000
Sum
(Max
(Irra
dia
tion
(W
h/m
2))
)
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
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20
13
20
08
20
09
20
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20
11
20
12
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13
20
08
20
09
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10
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11
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13
20
08
20
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20
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13
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08
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13
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08
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09
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13
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08
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09
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10
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11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
2 3 4 5 6 7 8 9 10 11 12
Year within Month
Year 2008 2009 2010 2011 2012 2013
Irradiation (kWh/m2)
Energy - Irradiation
0
100
Sum
(Max
(Ene
rgy/
Wpea
k (W
h/W
)))
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
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13
20
08
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09
20
10
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11
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12
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13
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08
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09
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10
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11
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13
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08
20
09
20
10
20
11
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12
20
13
20
08
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09
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10
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12
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13
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08
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09
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10
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11
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12
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13
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08
20
09
20
10
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11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
2 3 4 5 6 7 8 9 10 11 12
0
100000
200000
Sum
(Max
(Irra
dia
tion
(W
h/m
2))
)
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
20
10
20
11
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20
13
20
08
20
09
20
10
20
11
20
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20
13
20
08
20
09
20
10
20
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20
13
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08
20
09
20
10
20
11
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12
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13
20
08
20
09
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10
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11
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13
20
08
20
09
20
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20
11
20
12
20
13
20
08
20
09
20
10
20
11
20
12
20
13
20
08
20
09
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13
20
08
20
09
20
10
20
11
20
12
20
13
2 3 4 5 6 7 8 9 10 11 12
Year within Month
Year 2008 2009 2010 2011 2012 2013
Energy (kWh/kWp)
Irradiation (kWh/m2)
Do the sun-hours and the electricity-hours correlate?
Daily energy Yield versus irradiation 2008-2013
Ener
gy (k
Wh)
0
400
800
1200
1600
2000
2008 2009 2010 2011 2012 2013
Average Annual EnergyAnnual Energy (kWh)
1'6531'6441'878
1'4791'6031'564
Specific Yield (kWh/kWp)yearly 1043 1069 986 1252 1096 827
monthly 87 89 82 104 91 69daily 2.9 2.9 2.7 3.4 3.0 2.3
Elec
trici
ty (k
Wh/
kWp/
day)
0
2
4
6
8
Irradiation (kWh/m2/day)
0 2.25 4.5 6.75 9
Linear fits of daily energy-irradiation
Elec
trici
ty (k
Wh/
kWp/
day)
0
2
4
6
8
Irradiation (kWh/m2/day)
0 2.25 4.5 6.75 9
y = 0.8194x - 0.1653
y = 0.7335x - 0.0134
y = 0.8723x - 0.0956
y = 0.8298x - 0.0591
y = 0.8949x - 0.0299
y = 0.914x + 0.1291
Irrad'08 (kWh) Irrad'09 (kWh) Irrad'10 (kWh)Irrad'11 (kWh) Irrad'12 (kWh) Irrad'13 (kWh) m d
2008 0.914 0.129
2009 0.895 -0.030
2010 0.830 -0.059
2011 0.872 -0.096
2012 0.733 -0.013
2013 0.819 -0.165
Lowest system performance in the year 2012 due to broken PV-modules.
Conclusions• Energy yields vary:
- strongly looking on a monthly basis (up to 135% for some months) - less on a year to year basis (only 8% over the past 5 years).
• A convenient figure comparing solarPV systems is the specific yield (Ya) on an annual time scale. It gives comparison of all sizes of PV-systems.
• Yields correlate well with the sun irradiation.
• Correlating irradiance with yield brings up operational problems of the PV-system.
Further reading
See us on www.gomicromorph.com !http://gomicromorph.blogspot.ch/ !twitter.com/goMicromorph !ch.linkedin.com/in/gomicromorph/ !http://www.youtube.com/user/goMicromorph !http://www.slideshare.net/PVschool !https://itunes.apple.com/ch/artist/luc-feitknecht/id513205568?l=en&mt=11
More reading
You may like also • Cloud enhancement: a few slides
on the surprising effect of clouds boosting the solarPV yieldhttp://www.slideshare.net/PVschool/clouds2-25195039 !!!
• The cost of solar electricity: the key to solar electricity is sun and cheap moneyhttp://www.slideshare.net/PVschool/cost-of-solar-electricity !