SolarEdge Distributed Solar Power Harvesting. Field results of comparative energy maximization case studies. Presented in EUPVSEC 2010

1. Field Results of Energy Maximizing
Distributed DC Topology –
Residential & Commercial Installations
John Berdner, SolarEdge
General Manager for North America
8. September, 2010
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2. Energy Loss Factors in Traditional PV Systems
System Energy Loss Design Energy Loss
 Module mismatch  Limited roof utilization due
to design constraints
 Partial shading
 Undervoltage/Overvoltage Indirect Energy Loss
 Dynamic weather MPPT loss  No module level monitoring
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3. SolarEdge System Overview
 Module level optimization  Module level monitoring
 Fixed voltage - ideal installation  Enhanced safety solution
Power Optimizer
Inverter
Monitoring Server Internet
Monitoring Portal
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4. SolarEdge Distributed Technology
 ASIC-based Power Optimizers achieve:
 Per-module Maximum Power Point Tracking (MPPT)
 Efficiency: 98.8% EU weighted (99.5% peak)
 Conversion modes: buck, boost and buck/boost
 Wide module compatibility: 5v-125v, up to 400w
 Power Line Communication transceiver
 Module shut-down unless connected to an operating inverter
250/300/400W 350W Thin Film 250/350W Module
Module Add-on Module Add-on Embedded
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5. Fixed String Voltage - Enabler
String voltage is always fixed, regardless of temperature
and string length
 Flexible design for increased roof utilization:
⁻ Parallel strings of unequal lengths
⁻ Modules on multiple roof facets
⁻ Modules with different power ratings
⁻ Modules of different technologies
 Longer strings lead to savings on wiring and BoS components
String voltage is always optimal for DC/AC conversion
 High inversion efficiency: VDC ≝ VAC·√2+ε
 Prevention of under/over voltage situations
 Inverter cost reduction
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6. Field Trials and Results
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7. Roof Utilization Case Study – Israel
 Optimal roof space utilization enabled a 15kW residential installation
 Four facets covered
 Unmatched modules in each string were necessary:
 Different module sizes (and rating)
 Different tilt and azimuth
 25 Suntech 280W modules
 34 Suntech 210W modules
 4 Suntech 185W modules
 One power optimzier per
module
 3 SolarEdge SE5000 inverters
 1 string per inverter:
20, 20, 23 modules
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8. Roof Utilization Case Study – Results
 Module-level monitoring reveals:
 No mismatch losses (module-level MPPT)
 No string mismatch losses (length agnostic fixed string voltage)
 Attractive 5.1 kWh/kWp per day during August (compared to 5.5 for South-only sites)
280w 280w
West East
210w 210w
West East 280w 280w
East West
210w 210w
East West
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9. Comparative Energy Case Study Methodology
 Side by side energy comparisons under similar conditions:
 Standard inverter compared to distributed system
 Both systems subjected to:
 Identical total DC capacity (otherwise comparing kWh/kWp)
 Identical module tilt and orientation
 Identical irradiance and temperature conditions
 Identical shading scenarios Power
Optimizer
Power
Optimizer
Power
Optimizer
Power
Optimizer
Traditional system ©2010 SolarEdge Distributed system 9

10. Comparative Case Study 1 - Italy
 Power optimizers + SE5000 compared to four traditional inverters of
various brands (5kW, 5kW, 3kW, 6kW)
 Comparison without shading, and with simulated shading.
 Experiments done by Albatech, a MetaSystem Group company, an Italian
MW-scale turn-key integrator, and a technology oriented PV distributor.
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11. Comparative Case Study 1 – Unshaded
 Under unshaded conditions distributed system produced
2.3% - 6.4% more energy than the traditional inverters
Energy Production 06-15 July 2010
60.00
50.00
Power Optimizers
40.00
kWh
30.00
+ SE5000
20.00
10.00
0.00
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12. Comparative Case Study 1 – Shaded
 A cardboard panel was used to simulate a chimney-like sliding
shadow on 1-2 modules in each string with a distributed system
and inverter A
 The best performing inverter of three other un-shaded traditional
inverters was used as a reference
SolarEdge Inverter A
Distributed
System
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13. Comparative Case Study 1 – Shaded (Cont.)
 In reference to the unshaded inverter:
The distributed system recovered more than 50% of the energy
lost by traditional inverter A due to shading (-4% vs. to -8.63%)
Shaded Unshaded
6.00
5.65
5.43
5.00 5.20 5.21 5.27
4.00
Power Optimizers
kWh
3.00
2.00
+ SE5000
1.00
0.00
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* Inverter B was disconnected due to a technical issue during this test

14. Comparative Case Study 2 – Czech Republic
 Power optimizers + SE5000 compared to 5kW inverter of a leading brand
 Each inverter connected to 2 strings x 12 AWS modules x 185w = 4.4kWp
 Three partly shaded modules in each string of each system
 A third system remains unshaded for reference
 Test performed by American Way Solar, one of CZ largest PV distributors
Unshaded
reference
Shaded
SE5000
Shaded
traditional 14
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15. Comparative Case Study 2 – Results
 The distributed system produced 30.3% more energy than the
traditional inverter (58.96 kWh vs. 45.25 kWh)
 In reference to the unshaded inverter, the distributed system
recovered 77% of the energy lost by the traditional inverter due to
shading (6.5% loss vs. 28.3% loss)
14 70
Shaded Unshaded Shaded
12 60
63.12
58.96
Daily energy, kWh
10 50
Total energy, kWh
8 40 45.25
6 30
4 20
2 10
0 0
1 2 3
Power Optimizers + SE5000
Traditional Inverter 15
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16. Comparative Case Study 3 - Germany
 Power optimizers + SE5000 compared to traditional 5kW inverter
with multiple MPP trackers
 2 string x 12 and 13 Solon P210 modules x 210w = 5.25kWp
 A section inside a large scale PV field
 No shading
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17. Comparative Case Study 3 - Results
 The distributed system produced 1.65% more energy than the traditional
inverter
 On days with dynamic weather conditions, distributed module-level MPPT
recovers energy otherwise lost due to delayed MPPT process
Power Module-level MPPT energy
Power Optimizers + SE5000
gain on that day: +2.9%
Traditional Inverter
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18. The Impact of Dynamic Weather Conditions
 As shown in comparative case study 3, moving clouds induce rapid
fluctuations in irradiance level
 Centralized inverters are Sep 2nd 2010
more limited in their ability
to track changes in Imp
as fast as they occur,
compared to module-level
MPP trackers
10:00 – 11:00
±3kW fluctuations exhibited
for a 5kW inverter in the
span of minutes
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19. Comparative Case Study 4 – Germany
 Power optimizers + SE5000 compared to traditional 5kw inverter
with several MPP trackers
 2 strings x 9 Trina TSM220 modules x 220w = 3.96kWp
 Artificial shading simulating commercial layout inter-row shading
covers 0.5% of the PV array
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20. Comparative Case Study 4 – Results
 The distributed system produced 4% - 8% more energy than the
traditional inverter on most days of the month
 Distributed system production was lower on days with very low
irradiance, due to sizable self consumption of the prototype DSP
version of the unit, now replaced by an efficient ASIC
SolarEdge Daily Energy gain
vs. traditional inverter [%]
Introduction
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21. Comparative Case Study 5 – Spain
Layout
 Power optimizers + SE5000 compared to traditional inverter of a
leading brand
 2 strings x 7 BP 3200N modules x 200w = 2.8kWp
Shading
 Shade from a nearby
electricity cable
 Typical of residential
sites
 Module-level
monitoring revealed
shading pattern
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22. Comparative Case Study 5 – Results
 Accumulated Energy comparisons shows the distributed system
consistently produces 4% more energy than the traditional inverter
Traditional [kWh]
SolarEdge [kWh]
Energy Gain in [%]
Weekly Energy
Gain [%]
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23. Comparative Case Study 6 - Spain
Inverters
 Power optimziers + SE6000 compared to two traditional 3kw inverters
 4 strings x 10 Isofoton IS-150P modules x 150w = 6 kWp
Shading
Inter-row
 Inter-row shading shading
 Typical of commercial roof
with dense installations
 Modules are shaded for
2-3 hours every morning
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24. Comparative Case Study 6 - Results
 The distributed system produced 4.5% more energy on average
than the traditional inverter.
 On sunny days the
distributed system produced
up to 14% more energy due
to intensified partial shading
 On very cloudy days the
distributed system produced
2% – 3% more energy.
Clouds and low irradiance
cast diffuse light with little
or no partial shading.
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25. Questions
how what where
when why
how
Questions!
what where
who
when why who
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26. Thank you
John Berdner, General Manager North America
Website:
Email: John.berdner@solaredge.com www.solaredge.com
Twitter: www.twitter.com/SolarEdgePV
Blog: www.solaredge.com/blog
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©2010 SolarEdge