Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2012.6656791
R. Varieras, Jusong Wang, D. King
Low concentration photovoltaic (LCPV) module designs offer several advantages related to performance, cost, and potentially reliability. With only slight modification, widely available crystalline silicon cells can operate efficiently and reliably to about 3X concentration, which significantly reduces the cell contribution to module cost and also provides a large acceptance angle for solar tracking tolerance. These module designs also benefit from the use of materials and manufacturing processes common to the mature and field proven crystalline silicon PV industry. This paper discusses the unique performance characteristics considered in measuring and modeling the performance of Solaria LCPV modules and systems, along with measured comparisons versus conventional silicon PV technologies.
{"title":"System performance considerations for low concentration linear-focus silicon-based photovoltaic modules","authors":"R. Varieras, Jusong Wang, D. King","doi":"10.1109/pvsc-vol2.2012.6656791","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2012.6656791","url":null,"abstract":"Low concentration photovoltaic (LCPV) module designs offer several advantages related to performance, cost, and potentially reliability. With only slight modification, widely available crystalline silicon cells can operate efficiently and reliably to about 3X concentration, which significantly reduces the cell contribution to module cost and also provides a large acceptance angle for solar tracking tolerance. These module designs also benefit from the use of materials and manufacturing processes common to the mature and field proven crystalline silicon PV industry. This paper discusses the unique performance characteristics considered in measuring and modeling the performance of Solaria LCPV modules and systems, along with measured comparisons versus conventional silicon PV technologies.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"85 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76842873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2013.6656733
H. J. Choi, M. Bertoni, J. Hofstetter, D. Fenning, D. M. Powell, S. Castellanos, T. Buonassisi
Isothermal annealing above 1250 °C has been reported to reduce the dislocation density in multicrystalline silicon (mc-Si), presumably by pairwise dislocation annihilation. However, this high-temperature process may also cause significant impurity contamination, canceling out the positive effect of dislocation density reduction on cell performance. Here, efforts are made to annihilate dislocations in mc-Si in temperatures as low as 820 °C, with the assistance of an additional driving force to stimulate dislocation motion. A reduction of more than 60% in dislocation density is observed for mc-Si containing intermediate concentrations of certain metallic species after P gettering at 820 °C. While the precise mechanism remains in discussion, available evidence suggests that the net unidirectional flux of impurities in the presence of a gettering layer may cause dislocation motion, leading to dislocation density reduction. Analysis of minority carrier lifetime as a function of dislocation density suggests that lifetime improvements after P diffusion in these samples can be attributed to the combined effects of dislocation density reduction and impurity concentration reduction. These findings suggest there may be mechanisms to reduce dislocation densities at standard solar cell processing temperatures.
{"title":"Dislocation density reduction during impurity gettering in multicrystalline silicon","authors":"H. J. Choi, M. Bertoni, J. Hofstetter, D. Fenning, D. M. Powell, S. Castellanos, T. Buonassisi","doi":"10.1109/pvsc-vol2.2013.6656733","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2013.6656733","url":null,"abstract":"Isothermal annealing above 1250 °C has been reported to reduce the dislocation density in multicrystalline silicon (mc-Si), presumably by pairwise dislocation annihilation. However, this high-temperature process may also cause significant impurity contamination, canceling out the positive effect of dislocation density reduction on cell performance. Here, efforts are made to annihilate dislocations in mc-Si in temperatures as low as 820 °C, with the assistance of an additional driving force to stimulate dislocation motion. A reduction of more than 60% in dislocation density is observed for mc-Si containing intermediate concentrations of certain metallic species after P gettering at 820 °C. While the precise mechanism remains in discussion, available evidence suggests that the net unidirectional flux of impurities in the presence of a gettering layer may cause dislocation motion, leading to dislocation density reduction. Analysis of minority carrier lifetime as a function of dislocation density suggests that lifetime improvements after P diffusion in these samples can be attributed to the combined effects of dislocation density reduction and impurity concentration reduction. These findings suggest there may be mechanisms to reduce dislocation densities at standard solar cell processing temperatures.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"30 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82369991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2013.6656714
Minjae Kim, M. C. Clingerman, Alex W. Kawczak, P. R. Berger
Technical and economic viability of photovoltaic (PV) technology are governed by three parameters: efficiency, cost and lifetime. Since its inception, the main driver in organic photovolatics (OPV) research has been towards achieving high efficiency. Continued effort was fructified as achievement of 10 % efficiency, which was considered as a break-even point for commercial viability. Shifting of focus to lifetime is a next logical step. Increase lifetime of OPV by reliable encapsulation enhances technical feasibility and economic viability. So far, focus has been given on encapsulation barrier films, and little effort has been made on sealants; of this limited effort, the testing of existing commercial sealants is the general trend. Requirements of Sealants for OPV encapsulation include compatibility with low-cost and low-temperature OPV processing, lightness, flexibility, transparency, as well as thermal and UV stability. Hybrid sealants take advantages of good permeability of inorganic sealants and flexibility of organic sealants. In this contribution, we report on the demonstration of new flexible hybrid prototype sealants by calcium corrosion test. Sealants are screen-printable, flexible and can be cured at 130 °C in 15 minutes. Sealing capability of our hybrid sealants was compared with commercial silicone based hybrid sealant, i.e. polydimethylsiloxane (PDMS).
{"title":"Demonstration of hybrid prototype sealant for encapsulating organic photovoltaics","authors":"Minjae Kim, M. C. Clingerman, Alex W. Kawczak, P. R. Berger","doi":"10.1109/pvsc-vol2.2013.6656714","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2013.6656714","url":null,"abstract":"Technical and economic viability of photovoltaic (PV) technology are governed by three parameters: efficiency, cost and lifetime. Since its inception, the main driver in organic photovolatics (OPV) research has been towards achieving high efficiency. Continued effort was fructified as achievement of 10 % efficiency, which was considered as a break-even point for commercial viability. Shifting of focus to lifetime is a next logical step. Increase lifetime of OPV by reliable encapsulation enhances technical feasibility and economic viability. So far, focus has been given on encapsulation barrier films, and little effort has been made on sealants; of this limited effort, the testing of existing commercial sealants is the general trend. Requirements of Sealants for OPV encapsulation include compatibility with low-cost and low-temperature OPV processing, lightness, flexibility, transparency, as well as thermal and UV stability. Hybrid sealants take advantages of good permeability of inorganic sealants and flexibility of organic sealants. In this contribution, we report on the demonstration of new flexible hybrid prototype sealants by calcium corrosion test. Sealants are screen-printable, flexible and can be cured at 130 °C in 15 minutes. Sealing capability of our hybrid sealants was compared with commercial silicone based hybrid sealant, i.e. polydimethylsiloxane (PDMS).","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"22 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79099950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2012.6656723
N. Ahsan, N. Miyashita, M. M. Islam, K. Yu, W. Walukiewicz, Y. Okada
We present a comparative study on the material properties and two photon excitation (TPE) experiments involving three bands between a GaNAs and a GaNAsSb absorber designed for intermediate band solar cells. The absorber layers were sandwiched between p-AlGaAs emitter layers and n-AlGaAs IB barrier layers. This permits production of above the bandgap electron-hole pairs by TPE involving two subband photons with the intermediate band as the stepping stone. A recovery in the carrier population in the intermediate band of the GaNAsSb absorber was realized due to an improved material quality. An enhancement in the photocurrent production due to TPE, and an associated improvement in the open circuit voltage were observed.
{"title":"Effect of Sb on GaNAs intermediate band solar cells","authors":"N. Ahsan, N. Miyashita, M. M. Islam, K. Yu, W. Walukiewicz, Y. Okada","doi":"10.1109/pvsc-vol2.2012.6656723","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2012.6656723","url":null,"abstract":"We present a comparative study on the material properties and two photon excitation (TPE) experiments involving three bands between a GaNAs and a GaNAsSb absorber designed for intermediate band solar cells. The absorber layers were sandwiched between p-AlGaAs emitter layers and n-AlGaAs IB barrier layers. This permits production of above the bandgap electron-hole pairs by TPE involving two subband photons with the intermediate band as the stepping stone. A recovery in the carrier population in the intermediate band of the GaNAsSb absorber was realized due to an improved material quality. An enhancement in the photocurrent production due to TPE, and an associated improvement in the open circuit voltage were observed.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"15 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85925163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2013.6656699
Y. Shoji, K. Akimoto, Y. Okada
We have fabricated and characterized InGaAs/GaAsSb quantum dots solar cells (QDSCs) with a type-II band alignment structure. The photoluminescence (PL) spectrum indicates that radiative recombination in QDs is suppressed by embedding QDs with GaAsSb layers. In the excitation power dependence of PL, the PL peak of QDs embedded with GaAsSb layers show a large blueshift as reported for the case of a type-II band alignment. The external quantum efficiency (EQE) of QDSC increases in the longer wavelength range due to additive contributions from QD layers inserted in the intrinsic region. Further, an EQE increase due to photocurrent production by 2-step photon absorption measured for samples with InGaAs/GaAsSb structure indicates a higher response compared to the sample without GaAsSb layers.
{"title":"InGaAs/GaAsSb type-II quantum dots for intermediate band solar cell","authors":"Y. Shoji, K. Akimoto, Y. Okada","doi":"10.1109/pvsc-vol2.2013.6656699","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2013.6656699","url":null,"abstract":"We have fabricated and characterized InGaAs/GaAsSb quantum dots solar cells (QDSCs) with a type-II band alignment structure. The photoluminescence (PL) spectrum indicates that radiative recombination in QDs is suppressed by embedding QDs with GaAsSb layers. In the excitation power dependence of PL, the PL peak of QDs embedded with GaAsSb layers show a large blueshift as reported for the case of a type-II band alignment. The external quantum efficiency (EQE) of QDSC increases in the longer wavelength range due to additive contributions from QD layers inserted in the intrinsic region. Further, an EQE increase due to photocurrent production by 2-step photon absorption measured for samples with InGaAs/GaAsSb structure indicates a higher response compared to the sample without GaAsSb layers.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"53 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88115669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2013.6656775
Deming Zhang, J. Russo, M. Gordon, S. Vorndran, R. Kostuk
Light trapping is a useful approach for increasing the absorption of thin film photovoltaic (PV) cells. Simple light trapping can be achieved by incorporating a scattering layer on the top and bottom surface of cells and can increase absorption by a factor of 4n2. Recently, ultralight trapping using Rugate and 1-D photonic bandgap filters have been proposed to increase light trapping by a factor of 4n2 /sin2θ, where θ is half of the acceptance angle. In this paper, we present the design of a holographic ultralight trapping filter. The holographic filter can be implemented in large areas at a low cost, which makes it scalable for PV applications. A design is presented that increases the optical path length for near bandgap wavelengths in a thin-film silicon PV cell. The optical path length enhancement is converted to electrical output using the PC-1D simulation software. The short-circuit current for a 10-µm-thick silicon PV cell increases by nearly 14.7% relative to a cell without light trapping.
{"title":"Ultralight-trapping filters with volume reflection holograms","authors":"Deming Zhang, J. Russo, M. Gordon, S. Vorndran, R. Kostuk","doi":"10.1109/pvsc-vol2.2013.6656775","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2013.6656775","url":null,"abstract":"Light trapping is a useful approach for increasing the absorption of thin film photovoltaic (PV) cells. Simple light trapping can be achieved by incorporating a scattering layer on the top and bottom surface of cells and can increase absorption by a factor of 4n2. Recently, ultralight trapping using Rugate and 1-D photonic bandgap filters have been proposed to increase light trapping by a factor of 4n2 /sin2θ, where θ is half of the acceptance angle. In this paper, we present the design of a holographic ultralight trapping filter. The holographic filter can be implemented in large areas at a low cost, which makes it scalable for PV applications. A design is presented that increases the optical path length for near bandgap wavelengths in a thin-film silicon PV cell. The optical path length enhancement is converted to electrical output using the PC-1D simulation software. The short-circuit current for a 10-µm-thick silicon PV cell increases by nearly 14.7% relative to a cell without light trapping.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"111 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78410777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2013.6656766
T. Nakada, Taizou Kobayashi, T. Kumazawa, H. Yamaguchi
Thepostdeposition treatments, such as ammonia rinsing, light soaking, and heat light soaking on cell performances of Cu(In,Ga)Se2 (CIGS) solar cells with Zn-compound buffer layers, are investigated. The impacts of these treatments are discussed in connection with the band alignment at the transparent conducting oxide (TCO)/buffer/CIGS interface. Three types of CIGS solar cells with sputter-deposited ZnO:Al/CBD-ZnS(O,OH), MOCVD-ZnO:B/CBD-ZnS(O,OH), and MOCVD-ZnO:B/ALD-Zn(O,S) are investigated in this paper. The importance of the combination of buffer/TCO materials and deposition processes is discussed. We demonstrate that the adjustment of an S/(S+O) atomic ratio relevant to the band alignment at the buffer/CIGS interface is critical to achieve high-efficiency CIGS solar cells with Zn-compound buffer layer.
{"title":"Impacts of post-treatments on cell performance of CIGS solar cells with Zn-compound buffer layers","authors":"T. Nakada, Taizou Kobayashi, T. Kumazawa, H. Yamaguchi","doi":"10.1109/pvsc-vol2.2013.6656766","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2013.6656766","url":null,"abstract":"Thepostdeposition treatments, such as ammonia rinsing, light soaking, and heat light soaking on cell performances of Cu(In,Ga)Se2 (CIGS) solar cells with Zn-compound buffer layers, are investigated. The impacts of these treatments are discussed in connection with the band alignment at the transparent conducting oxide (TCO)/buffer/CIGS interface. Three types of CIGS solar cells with sputter-deposited ZnO:Al/CBD-ZnS(O,OH), MOCVD-ZnO:B/CBD-ZnS(O,OH), and MOCVD-ZnO:B/ALD-Zn(O,S) are investigated in this paper. The importance of the combination of buffer/TCO materials and deposition processes is discussed. We demonstrate that the adjustment of an S/(S+O) atomic ratio relevant to the band alignment at the buffer/CIGS interface is critical to achieve high-efficiency CIGS solar cells with Zn-compound buffer layer.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"24 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78543936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2013.6656737
S. Pattnaik, T. Xiao, R. Shinar, J. Shinar, V. Dalal
We report on a novel hybrid amorphous Si-organic series-connected tandem junction solar cell. The solar cell is fabricated on indium tin oxide (ITO)-coated glass and uses an a-(Si,C):H as the first cell and a P3HT/PCBM organic cell as the second cell. An intermediate ITO layer is used as an ohmic layer which provides an excellent contact to both the first and the second cells. By adjusting the bandgap and thickness of the first a-(Si,C):H cell, we achieve an almost complete matching of currents produced by the first and the second cells. The first cell produces ∼0.95–1.0-V open-circuit voltage, and the second cell produces ∼0.6-V open-circuit voltage. The combined cell produces 1.5-V open-circuit voltage and had a fill factor of 77%, showing the effectiveness of the intermediate ITO layer to act as an excellent connecting layer between the two cells.When such an ITO layer is not used, the fill factor is very poor. The solar conversion efficiency of the organic cell was 4.3%, whereas the efficiency of the tandem cell was 5.7%. We also measured the stability of the organic cell with and without an inorganic cell acting as a filter in front. It is shown that the degradation of the organic cell is much higher when it is subjected to a full solar spectrum, as compared with when it is subjected to light passing through an inorganic cell first, which filters out ultraviolet (UV) and blue photons. Thus,we showthat this new cell combination has the potential to significantly increase the efficiency of organic cells while also decreasing the instability. We also discuss the potential of achieving much higher efficiencies, that is approaching 20%, by using an appropriate combination of amorphous and organic cells. An example is shown next.
{"title":"Novel hybrid amorphous/organic tandem junction solar cell","authors":"S. Pattnaik, T. Xiao, R. Shinar, J. Shinar, V. Dalal","doi":"10.1109/pvsc-vol2.2013.6656737","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2013.6656737","url":null,"abstract":"We report on a novel hybrid amorphous Si-organic series-connected tandem junction solar cell. The solar cell is fabricated on indium tin oxide (ITO)-coated glass and uses an a-(Si,C):H as the first cell and a P3HT/PCBM organic cell as the second cell. An intermediate ITO layer is used as an ohmic layer which provides an excellent contact to both the first and the second cells. By adjusting the bandgap and thickness of the first a-(Si,C):H cell, we achieve an almost complete matching of currents produced by the first and the second cells. The first cell produces ∼0.95–1.0-V open-circuit voltage, and the second cell produces ∼0.6-V open-circuit voltage. The combined cell produces 1.5-V open-circuit voltage and had a fill factor of 77%, showing the effectiveness of the intermediate ITO layer to act as an excellent connecting layer between the two cells.When such an ITO layer is not used, the fill factor is very poor. The solar conversion efficiency of the organic cell was 4.3%, whereas the efficiency of the tandem cell was 5.7%. We also measured the stability of the organic cell with and without an inorganic cell acting as a filter in front. It is shown that the degradation of the organic cell is much higher when it is subjected to a full solar spectrum, as compared with when it is subjected to light passing through an inorganic cell first, which filters out ultraviolet (UV) and blue photons. Thus,we showthat this new cell combination has the potential to significantly increase the efficiency of organic cells while also decreasing the instability. We also discuss the potential of achieving much higher efficiencies, that is approaching 20%, by using an appropriate combination of amorphous and organic cells. An example is shown next.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"146 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77247858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2012.6656763
A. Mills, R. Wiser
We estimate the long-run economic value of photovoltaic (PV) generation with increasing penetration using a unique investment and dispatch model that captures long-run investment decisions while also incorporating detailed operational constraints and hourly time resolution over a full year. High time resolution and operational constraints can be important for estimating the economic value of variable generation resources like PV, as is the use of a modeling framework that accommodates new investment decisions. The model is herein applied to a case study that is loosely based on California in 2030. The marginal economic value of PV is decomposed into capacity value, energy value, day-ahead forecast error cost, and ancillary services. The value of PV is found to exceed the value of a flat block of power by $19/MWh at low penetration, largely due to the high capacity value of PV at low penetration. The value of PV is found to drop considerably (by more than $60/MWh) as the penetration increases toward 30% on an energy basis, first due primarily to a steep drop in the capacity value followed by a decrease in the energy value. Day-ahead forecast error and ancillary service costs, though not insignificant, do not change as dramatically with increasing penetration. In the near term, efforts to mitigate changes in the value of PV with increasing penetration may be most effective if focused on maintaining the capacity value of PV.
{"title":"Changes in the economic value of photovoltaic generation at high penetration levels: A pilot case study of California","authors":"A. Mills, R. Wiser","doi":"10.1109/pvsc-vol2.2012.6656763","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2012.6656763","url":null,"abstract":"We estimate the long-run economic value of photovoltaic (PV) generation with increasing penetration using a unique investment and dispatch model that captures long-run investment decisions while also incorporating detailed operational constraints and hourly time resolution over a full year. High time resolution and operational constraints can be important for estimating the economic value of variable generation resources like PV, as is the use of a modeling framework that accommodates new investment decisions. The model is herein applied to a case study that is loosely based on California in 2030. The marginal economic value of PV is decomposed into capacity value, energy value, day-ahead forecast error cost, and ancillary services. The value of PV is found to exceed the value of a flat block of power by $19/MWh at low penetration, largely due to the high capacity value of PV at low penetration. The value of PV is found to drop considerably (by more than $60/MWh) as the penetration increases toward 30% on an energy basis, first due primarily to a steep drop in the capacity value followed by a decrease in the energy value. Day-ahead forecast error and ancillary service costs, though not insignificant, do not change as dramatically with increasing penetration. In the near term, efforts to mitigate changes in the value of PV with increasing penetration may be most effective if focused on maintaining the capacity value of PV.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"11 5 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80401130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-01-01DOI: 10.1109/pvsc-vol2.2012.6656788
C. Thompson, S. Hegedus, P. Carcia, R. S. Mclean
In Cu(In,Ga)Se2 solar cells encapsulated with polyethylene terephthalate (PET) or glass top sheets, the effects of damp heat (D-H) accelerated lifetime testing (ALT) depend on water vapor transmission rate (WVTR) of both transparent conducting oxide (TCO) and the intrinsic zinc oxide (i-ZnO) buffer, as well as device geometry. PET top sheets have a WVTR of ∼10 g/m2·day, and glass has a WVTR of 0. Previously, coupons encapsulated with PET degraded to 50% of initial efficiency after 1000 h D-H ALT. We show that PET encapsulated coupons degrade at the same rate as glass encapsulated coupons after 2000 h D-H ALT to 92% of initial efficiency. The only change from previous work is that, here, i-ZnO covers the entire coupon surface, not the just active area. The WVTR of the i-ZnO/TCO stack is 2 × 10−3 g·H2 O/m2·day. A set of unencapsulated devices went through D-H ALT, one where scribing was used to define the active area of the device and another without scribing; both were protected only by 50-nm i-ZnO. The bare-unscribed device performed as well as the previous glass and PET encapsulated coupons after 1500 h D-H ALT; the bare-scribed device degraded to 78% of initial efficiency, indicating that TCO integrity is a critical ALT parameter.
在用聚对苯二甲酸乙二醇酯(PET)或玻璃顶片封装的Cu(In,Ga)Se2太阳能电池中，湿热(D-H)加速寿命测试(ALT)的影响取决于透明导电氧化物(TCO)和固有氧化锌(i-ZnO)缓冲液的水蒸气透过率(WVTR)，以及器件的几何形状。PET顶板的WVTR为~ 10 g/m2·天，玻璃的WVTR为0。之前，用PET封装的薄片在1000 h D-H ALT后降解到初始效率的50%。我们发现，PET封装的薄片在2000 h D-H ALT后降解率与玻璃封装的薄片相同，达到初始效率的92%。与以前的研究相比，唯一的变化是，在这里，i-ZnO覆盖了整个复合材料表面，而不仅仅是活性区域。i-ZnO/TCO堆的WVTR为2 × 10−3 g·H2 O/m2·day。一组未封装的设备通过D-H ALT，其中一组使用划线来定义设备的活动区域，另一组不使用划线;两者都仅被50 nm的i-ZnO保护。在1500 h D-H ALT后，裸裸装置的性能与先前的玻璃和PET封装的薄片一样好;裸刻器件的效率下降到初始效率的78%，表明TCO完整性是一个关键的ALT参数。
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