How much energy really gets lost from Partial Shading?
Upcoming SlideShare
Loading in...5
×
 

How much energy really gets lost from Partial Shading?

on

  • 812 views

It is a well-known fact that modules interfere negatively with each other in a serial connection; while the modules’ peak operating points are diverse, traditional inverters use a ...

It is a well-known fact that modules interfere negatively with each other in a serial connection; while the modules’ peak operating points are diverse, traditional inverters use a ‘one-size-fits-all’ approach to harvest their energy. Partial shading, or uneven exposure to sunlight, diversifies the modules even further as some can produce more than others now.

Statistics

Views

Total Views
812
Views on SlideShare
812
Embed Views
0

Actions

Likes
1
Downloads
4
Comments
0

0 Embeds 0

No embeds

Accessibility

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

     How much energy really gets lost from Partial Shading? How much energy really gets lost from Partial Shading? Presentation Transcript

    • Field Results of Energy Maximizing Distributed DC Topology – Residential & Commercial Installations John Berdner, SolarEdge General Manager for North America 8. September, 2010 1
    • 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 ©2010 SolarEdge 2
    • SolarEdge System Overview  Module level monitoring  Module level optimization  Fixed voltage - ideal installation  Enhanced safety solution Power Optimizer Inverter Monitoring Server Internet ©2011 SolarEdge Monitoring Portal 3
    • 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 350W Thin Film Module Add-on 250/300/400W Module Add-on ©2010 SolarEdge 250/350W Module Embedded 4
    • 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 ©2010 SolarEdge 5
    • Field Trials and Results ©2010 SolarEdge 6
    • 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 ©2010 SolarEdge 7
    • 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 West 210w West 280w East 210w East 280w East 210w East ©2010 SolarEdge 280w West 210w West 8
    • 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 Traditional system ©2010 SolarEdge Power Optimizer Power Optimizer Power Optimizer Power Optimizer Distributed system 9
    • 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. ©2010 SolarEdge 10
    • 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 kWh 40.00 30.00 20.00 10.00 Power Optimizers + SE5000 50.00 0.00 ©2010 SolarEdge 11
    • 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 Distributed System Inverter A ©2010 SolarEdge 12
    • 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 5.00 5.43 5.65 5.21 5.20 5.27 3.00 2.00 1.00 0.00 Power Optimizers + SE5000 kWh 4.00 ©2010 SolarEdge * Inverter B was disconnected due to a technical issue during this test 13
    • 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 ©2010 SolarEdge 14
    • 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 Shaded Daily energy, kWh 12 70 60 10 Shaded Unshaded 63.12 58.96 Total energy, kWh 50 8 45.25 40 6 30 4 20 2 10 0 0 1 Power Optimizers + SE5000 Traditional Inverter ©2010 SolarEdge 2 3 15
    • 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 ©2010 SolarEdge 16
    • 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 Power Optimizers + SE5000 Module-level MPPT energy gain on that day: +2.9% Traditional Inverter ©2010 SolarEdge 17
    • 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 ©2010 SolarEdge 18
    • 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 ©2010 SolarEdge 19
    • 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 Introduction SolarEdge Daily Energy gain vs. traditional inverter [%] ©2010 SolarEdge 20
    • 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 ©2010 SolarEdge ©2010 SolarEdge 21
    • Comparative Case Study 5 – Results Accumulated Energy comparisons shows the distributed system consistently produces 4% more energy than the traditional inverter Traditional [kWh] Energy Gain in [%]  ©2010 SolarEdge SolarEdge [kWh] Weekly Energy Gain [%] 22
    • 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 shading  Typical of commercial roof with dense installations  Modules are shaded for 2-3 hours every morning Inter-row shading ©2010 SolarEdge 23
    • 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. ©2010 SolarEdge 24
    • Questions what where how when why Questions! what where how when why who who ©2010 SolarEdge 25
    • Thank you John Berdner, General Manager North America Email: John.berdner@solaredge.com Twitter: www.twitter.com/SolarEdgePV Blog: www.solaredge.com/blog ©2010 SolarEdge Website: www.solaredge.com 26