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P3 m schweiger__spectral_analysis_of_thin_film_modules

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Sandia National Laboratories: Energy & Climate: Renewables
Sandia National Laboratories: Energy & Climate: Renewables

Spectral analysis of various thin film modules using high precision spectral response data and solar spectral irradiance data

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®TÜV,TUEVandTUVareregisteredtrademarks.Utilizationandapplicationrequirespriorapproval. ∫ ⋅⋅=≈ b a iSCPhoto dSREAII λλλ )()( 80% 90% 100% 110% 120% 1,55 1,57 1,59 1,61 1,63 1,65 1,67 1,69 1,71 1,73 1,75 ∆Isc[%] APE [eV] µ-Si This poster contains results of high-precision indoor and outdoor measurements of different PV module technologies performed at the headquarters of TÜV Rheinland, Cologne. Modules based on CdTe, CI(G)S, a-Si, a-Si/µ-Si, a-Si/a-Si and c-Si (mono and poly) semiconductors were analyzed nondestructively according to their spectral response and technology specific differences are pointed out. After the indoor characterization the modules were exposed outdoor for one year, steadily measuring the maximum power point PMPP and the I/V-curves with the corresponding solar spectrum. With this data volume it is possible to describe the spectral conditions at the test-site in Cologne using the APE-Method. In a next step the influence on the module performance and the energy yield of the different technologies are analyzed. The photo current is calculated theoretically by the integral of spectral response data and spectral measurements and compared to temperature and irradiance corrected real outdoor measurements. Depending on the position of the sun related to the module and the atmosphere the spectral distribution of solar irradiation can be shifted into blue or red wavelength areas. Some technologies can benefit while others may be disadvantaged depending on their spectral response. In what way and why these spectral shifts happen in the course of a day and the season and what influence they have on the energy yield of a certain technology are described in the following. Markus Schweiger, Ulrike Jahn, Werner Herrmann TÜV Rheinland Energie und Umwelt GmbH, Am Grauen Stein, 51105 Cologne, Germany Tel.: +49 221 806-5585, E-Mail: Markus.Schweiger@de.tuv.com RESULTS CONCLUSIONS SPECTRAL ANALYSIS OF VARIOUS THIN FILM MODULES USING HIGH PRECISION SPECTRAL RESPONSE DATA AND SOLAR SPECTRAL IRRADIANCE DATA Figure 1 Non-destructive measurement of the spectral response (SR) of a triple-junction module with the test equipment at TÜV Rheinland, Cologne Spectral response of different PV module technologies Characterizing solar spectrum with the average photon energy (APE) Influence of spectrum on performance and yield Since 2013 TÜV Rheinland runs extensive energy yield measurements at five different locations all over the world. Requests can be sent to the authors. Significant differences in SR-Signal of CIGS and a-Si specimens APE-Method appropriate method to describe solar spectrum Automatable procedure to correct T, G and MM implemented Sinus-shaped performance fluctuation of a-Si because of spectrum Spectrum not significant for energy yield of c-Si and most CIGS Annual gains of +3% (some a-Si) and +1% (CdTe) calculated in 11/12 INTRODUCTION 0,00 0,20 0,40 0,60 0,80 1,00 1,20 300 500 700 900 1100 1300 Rel.SpectralResponse. Wavelength [nm] Norm AM1.5 a-Si CIS CdTe CIGS poly c-Si mono c-Si CIGS 0,00 0,20 0,40 0,60 0,80 1,00 1,20 300 500 700 900 1100 1300 Rel.SpectralResponse Wavelength [nm] CI(G)S 0,00 0,20 0,40 0,60 0,80 1,00 1,20 300 400 500 600 700 800 900 1000 Rel.SpectralResponse Wavelength [nm] Top-Layer Bottom-Layer The SR-equipment is suitable for all common module designs (Fig. 1) Step-size 1nm for single-, double- and triple-junction specimens possible Large spread of the spectral response for different module technologies (Fig. 2) Also large technology internal spreads for a-Si and CIGS (Fig. 3 + 4) The spectral mismatch (MM) and the theoretical photo current can be calculated to improve PMax determination and outdoor monitoring 80% 90% 100% 110% 120% ∆Isc[%] CdTe 80% 90% 100% 110% 120% ∆Isc[%] CI(G)S & c-Si 80% 90% 100% 110% 120% ∆Isc[%] a-Si 80% 90% 100% 110% 120% ∆Isc[%] CdTe 80% 90% 100% 110% 120% ∆Isc[%] CI(G)S & c-Si 80% 90% 100% 110% 120% 1,55 1,57 1,59 1,61 1,63 1,65 1,67 1,69 1,71 1,73 1,75 ∆Isc[%] APE [eV] a-Si/µ-Si 80% 90% 100% 110% 120% ∆Isc[%] a-Si Spectrum < 1.65 eV red Spectrum > 1.65 eV blue Spectrum = 1.65 eV STC Winter red spectrum (Fig. 5 + 8) Calculated Measured 1,3 1,4 1,5 1,6 1,7 1,8 1,9 2 2,1 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 APE[eV] time AM1,5g Summer (21.08.2010) Fall (10.10.2010) Winter (29.01.2011) Spring (19.04.2011) 2 2,2 2,4 2,6 2,8 3 3,2 3,4 3,6 3,8 4 4,2 4,4 4,6 4,8 5 5,2 5,4 Isc[A] Isc: T,G corrected Isc: T,G,MM corrected )( )( )( λλ λ λ Pq I q hcSR QE Φ⋅ =⋅= Figure 5 Solar spectral irradiance drift for cloudless days in summer (blue), spring (green), fall (yellow) and winter (red) for modules mounted facing south and 35° tilted in Cologne Figure 9 Correcting spectral effects of an a-Si specimenFigure 8 Seasonal variations of APE-values and average APE-value per month Figure 6 Dependency of ISC on spectral changes, calculated with formula, normalized to ISC,STC at 1.65 eV Figure 7 Dependency of ISC on spectral changes, measured (T, G corrected), normalized to ISC,STC at 1.65 eV ∫ ∫ Φ⋅ = b a ie b a i dq dE APE λλ λλ )( )( Figure 2 Rel. spectral response signal of different PV- module technologies in comparison with IEC 60904-3 spectrum Figure 3 + 4 Rel. spectral response signal of different CIGS and a-Si modules, illustrating significant differences within the same thin-film technology Results of calculated and measured ISC (APE) almost similar (Fig. 6+7) Dependency of a-Si/µ-Si on spectrum screened out as combination of a-Si behavior for APE < 1.65eV and µ-Si behavior for APE > 1.65eV significant losses because of current mismatch expected Almost no dependency of c-Si and most CIGS on spectrum Strong dependency of a-Si and small dependency of CdTe on spectrum The seasonal average spectrum was calculated to 1.68 eV in 2011/12. Small energy yield gains of max. +3% (some a-Si) and +1% (CdTe).

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P3 m schweiger__spectral_analysis_of_thin_film_modules

  • 1. ®TÜV,TUEVandTUVareregisteredtrademarks.Utilizationandapplicationrequirespriorapproval. ∫ ⋅⋅=≈ b a iSCPhoto dSREAII λλλ )()( 80% 90% 100% 110% 120% 1,55 1,57 1,59 1,61 1,63 1,65 1,67 1,69 1,71 1,73 1,75 ∆Isc[%] APE [eV] µ-Si This poster contains results of high-precision indoor and outdoor measurements of different PV module technologies performed at the headquarters of TÜV Rheinland, Cologne. Modules based on CdTe, CI(G)S, a-Si, a-Si/µ-Si, a-Si/a-Si and c-Si (mono and poly) semiconductors were analyzed nondestructively according to their spectral response and technology specific differences are pointed out. After the indoor characterization the modules were exposed outdoor for one year, steadily measuring the maximum power point PMPP and the I/V-curves with the corresponding solar spectrum. With this data volume it is possible to describe the spectral conditions at the test-site in Cologne using the APE-Method. In a next step the influence on the module performance and the energy yield of the different technologies are analyzed. The photo current is calculated theoretically by the integral of spectral response data and spectral measurements and compared to temperature and irradiance corrected real outdoor measurements. Depending on the position of the sun related to the module and the atmosphere the spectral distribution of solar irradiation can be shifted into blue or red wavelength areas. Some technologies can benefit while others may be disadvantaged depending on their spectral response. In what way and why these spectral shifts happen in the course of a day and the season and what influence they have on the energy yield of a certain technology are described in the following. Markus Schweiger, Ulrike Jahn, Werner Herrmann TÜV Rheinland Energie und Umwelt GmbH, Am Grauen Stein, 51105 Cologne, Germany Tel.: +49 221 806-5585, E-Mail: Markus.Schweiger@de.tuv.com RESULTS CONCLUSIONS SPECTRAL ANALYSIS OF VARIOUS THIN FILM MODULES USING HIGH PRECISION SPECTRAL RESPONSE DATA AND SOLAR SPECTRAL IRRADIANCE DATA Figure 1 Non-destructive measurement of the spectral response (SR) of a triple-junction module with the test equipment at TÜV Rheinland, Cologne Spectral response of different PV module technologies Characterizing solar spectrum with the average photon energy (APE) Influence of spectrum on performance and yield Since 2013 TÜV Rheinland runs extensive energy yield measurements at five different locations all over the world. Requests can be sent to the authors. Significant differences in SR-Signal of CIGS and a-Si specimens APE-Method appropriate method to describe solar spectrum Automatable procedure to correct T, G and MM implemented Sinus-shaped performance fluctuation of a-Si because of spectrum Spectrum not significant for energy yield of c-Si and most CIGS Annual gains of +3% (some a-Si) and +1% (CdTe) calculated in 11/12 INTRODUCTION 0,00 0,20 0,40 0,60 0,80 1,00 1,20 300 500 700 900 1100 1300 Rel.SpectralResponse. Wavelength [nm] Norm AM1.5 a-Si CIS CdTe CIGS poly c-Si mono c-Si CIGS 0,00 0,20 0,40 0,60 0,80 1,00 1,20 300 500 700 900 1100 1300 Rel.SpectralResponse Wavelength [nm] CI(G)S 0,00 0,20 0,40 0,60 0,80 1,00 1,20 300 400 500 600 700 800 900 1000 Rel.SpectralResponse Wavelength [nm] Top-Layer Bottom-Layer The SR-equipment is suitable for all common module designs (Fig. 1) Step-size 1nm for single-, double- and triple-junction specimens possible Large spread of the spectral response for different module technologies (Fig. 2) Also large technology internal spreads for a-Si and CIGS (Fig. 3 + 4) The spectral mismatch (MM) and the theoretical photo current can be calculated to improve PMax determination and outdoor monitoring 80% 90% 100% 110% 120% ∆Isc[%] CdTe 80% 90% 100% 110% 120% ∆Isc[%] CI(G)S & c-Si 80% 90% 100% 110% 120% ∆Isc[%] a-Si 80% 90% 100% 110% 120% ∆Isc[%] CdTe 80% 90% 100% 110% 120% ∆Isc[%] CI(G)S & c-Si 80% 90% 100% 110% 120% 1,55 1,57 1,59 1,61 1,63 1,65 1,67 1,69 1,71 1,73 1,75 ∆Isc[%] APE [eV] a-Si/µ-Si 80% 90% 100% 110% 120% ∆Isc[%] a-Si Spectrum < 1.65 eV red Spectrum > 1.65 eV blue Spectrum = 1.65 eV STC Winter red spectrum (Fig. 5 + 8) Calculated Measured 1,3 1,4 1,5 1,6 1,7 1,8 1,9 2 2,1 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 APE[eV] time AM1,5g Summer (21.08.2010) Fall (10.10.2010) Winter (29.01.2011) Spring (19.04.2011) 2 2,2 2,4 2,6 2,8 3 3,2 3,4 3,6 3,8 4 4,2 4,4 4,6 4,8 5 5,2 5,4 Isc[A] Isc: T,G corrected Isc: T,G,MM corrected )( )( )( λλ λ λ Pq I q hcSR QE Φ⋅ =⋅= Figure 5 Solar spectral irradiance drift for cloudless days in summer (blue), spring (green), fall (yellow) and winter (red) for modules mounted facing south and 35° tilted in Cologne Figure 9 Correcting spectral effects of an a-Si specimenFigure 8 Seasonal variations of APE-values and average APE-value per month Figure 6 Dependency of ISC on spectral changes, calculated with formula, normalized to ISC,STC at 1.65 eV Figure 7 Dependency of ISC on spectral changes, measured (T, G corrected), normalized to ISC,STC at 1.65 eV ∫ ∫ Φ⋅ = b a ie b a i dq dE APE λλ λλ )( )( Figure 2 Rel. spectral response signal of different PV- module technologies in comparison with IEC 60904-3 spectrum Figure 3 + 4 Rel. spectral response signal of different CIGS and a-Si modules, illustrating significant differences within the same thin-film technology Results of calculated and measured ISC (APE) almost similar (Fig. 6+7) Dependency of a-Si/µ-Si on spectrum screened out as combination of a-Si behavior for APE < 1.65eV and µ-Si behavior for APE > 1.65eV significant losses because of current mismatch expected Almost no dependency of c-Si and most CIGS on spectrum Strong dependency of a-Si and small dependency of CdTe on spectrum The seasonal average spectrum was calculated to 1.68 eV in 2011/12. Small energy yield gains of max. +3% (some a-Si) and +1% (CdTe).