SunPower Cell & Module overview Stefano G. Alberici, PhD, Sr. Trainer EU, SunPower Corporation New Delhi, 17.10.2012, Rooftop Workshop India
2 PV classical stereotypes : Come on: A module is a module: they are all the same. The only thing that counts is the price. Why should I bother with other items? Come on: A kwp is a kwp: they are all the same. Their production (kwh/kwp/y) does not change when changing the module. The only thing that counts is the price. Why should I bother with other items? 2
Why you should bother? Here is why: SunPower a differentiated technology Most powerful PV modules in the market Industry leading panel efficiency: 20%, leading cell efficiency: 22,5% Produce up to 50% more than conventional panels and up to 4 times more than thin film panels per unit area Best energy performance (kwh/kwp), averaged +7 to +9 %/y more than the rest of PV Solid reliability & quality Industry s first 25-year combined power and product warranty 3
Module Efficiency SunPower technology is better 22% 20% 18% 16% 19% 20% 14% 16% 12% 14% Thin Film CdTe Standard Efficiency Selective Emitter HiT SunPower E-Series (12.2% mod) (16% cell) (19% cell) (20% cell) (22.5% cell) 4 4
Conventional solar: warranty returns 86% of conventional solar panel warranty returns: corrosion / cell / interconnect breaks Reliability of PV Systems. J Wohlgemuth. Proceedings of SPIE, presented 11-August-2008 5
Back side copper plating provides significant degradation advantage SunPower Cell Front contact cells Lines are alternating (+) and (-) copper conductors SunPower returns rate from 2006 to 2012: 33 ppm (200 / 6 milions) Plated interlaced copper conductors Ductile metal provide much more strength to the Silicon Even if the Silicon cracks, the copper fingers maintain full conductivity, so a cell crack causes no loss of cell area and no measureable power drop. Copper/tin plating is very robust against corrosion, and very easy to solder Screen-printed metal paste The baked-on paste offers no structural strength all the strength is from the brittle Silicon wafer itself. Very thin silver front-side metal lines oxidize/corrode over time 6
Most efficient cells in the industry SunPower cells are up to 50% more efficient than conventional solar cells due to unique all-back contact design SunPower Cells 22.5% efficiency Conventional cells Monocrystalline 15-17% efficiency Conventional cells Polycristalline 14-16% efficiency 7
Compared to SunPower cell technology Back contacts More = metal robust on cell the to No back cell shading connection = Higher losses durability & long-term & toughness operating life Conventional Design Breakthrough Design Stronger Materials Front Contact Cell Back Contact Cell Conventional Monocrystaline SunPower Cell
SunPower panels produce up to 50% more power per m 2 Highest Panel Efficiency by Manufacturer 20% 19% 18% 17% SunPower Panasonic Sanyo 16% 15% 14% SunTech SolarWorld REC Kyocera Solar Sharp BP Solar 13% 12% As published in Photon International, July 2011 13
Better low-light performance SunPower solar cells generate more power at low light levels relative to other technologies Voltage builds rapidly at low insolation levels Better performance in overcast conditions Inverter wakes up earlier and runs later SunPower SPR-90 Mono Crystalline Silicon Poly Crystalline Silicon CuInSe 2 Amorphous Silicon Sharper knee of curve at low light levels is indicative of better low light performance 15
Comparison SunPower vs. non SunPower: the effect of the Anti-Reflecting Glass on panels NON SPWR SPWR NON SPWR 16
Higher performance at higher temperatures Due to lower temperature coefficients and lower normal cell operating temperatures (NOCT), SunPower panels generate more energy at higher temperatures compared to standard c-si modules Temp Coefficient: SunPower -0.38% / C Std c-si -0.47% / C NOCT: SunPower 45 C +/-2 Std c-si 47 C +/-2 0 5 10 15 20 25 30 35 40 (C ) 17
Operating temperatures: SPRW vs. standard c-si Higher efficiency modules operate at lower temperatures because they convert more of the sun s energy to electricity lower efficiency modules convert it to heat instead Temperature difference Time (h) 18
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Highly accelerated life test (HALT) Solar Simulator UV Tester Dynamic Load Test Autoclave Damp Heat Test
Dynamic Load Test Results Competitor Power Loss = 2.1% SunPower Power Loss = 0% Electroluminescence images of a front-contact module and SunPower back contact module after dynamic load HALT stress (1000 cycles of +/-2400 Pa, equivalent to maximum wind load, of alternating pressure load on the glass)
Power Degradation Reliability testing data: damp heat Performance of SunPower and Traditional Front Contact Modules in Damp Heat (85 C, 85% RH) 110% 100% 90% 80% 70% 60% 50% 40% 30% 20% SunPower 1 2 3 4 5 6 7 10% 0 1000 2000 3000 4000 5000 6000 7000 8000 Number of Hours SunPower cells are highly resistant to corrosion 22
23 SunPower performs better in hot arid climates University of Arizona / Tucson Electric Test Yard SunPower panels generate 8% more energy than the average of the rest of the field For current SunPower panels: add 1-3% for AR glass plus 1% for rooftop temps 8% 11% more energy output Cronin, Alexander, et. al. Performance Reviews from the Tucson Electric Power Solar Test Yard, 2011 data update.
24 3 rd party study compilation Compilation of 10 large studies shows SunPower yield is well above the average mono- and poly-crystalline silicon PV Panel yield. For current SunPower panels: add 1-3% for AR glass plus 1% for rooftop temps 6.2% Average 9% more energy output in third-party Energy Yield Studies Rose, Doug, et. al. High-Confidence Prediction of Energy Production fro High-Eff PV Systems, 25 th PVSEC Valencia, Sept. 2010.
Industry s first 25-year combined power and product warranty POWER GUARANTEE More Power: at least 95% of the Minimum Peak Power for the first five years Less than 0.4% annual degradation for the subsequent 20 years More lifetime energy: 9.1% above the industry standard PRODUCT WARRANTY The solar industry s first 25 year product and power coverage Coverage of warranty replacement costs Financial stability and product reliability to back our commitment 26
Guaranteed nominal P (%) Power warranty: what s new Power warranty Product warranty Industry Standard Step: 90%: 10 years 80%: 25 years Previous SunPower Warranty Step: 90%: 12 years 80%: 25 years NEW SunPower warranty (as from July 1 st ) Linear: 95% for 5 years Year 6 25: -0.4%/yr 100 Industry Standard SunPower Previous Warranty SunPower New Linear Warranty 95 90 85 80 75 70 Years of performance 0 5 10 15 20 25 27
Industry leading 25-year product warranty Power warranty Product warranty Industry Standard Previous SunPower warranty The NEW SunPower warranty (as from July 1 st ) 5-10 years 10 years 25 years SunPower Hanhwa Solarworld, Sharp, First Solar, Suntech, Canadian, Trina, Yingli Jinko Solar Kyocera NA Years of performance 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 *Source: Companies websites & datasheets. Data as of 15 September 2012 28
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