G. Nofuentes

Solar Spectral and Module Temperature Influence on the Outdoor Performance of Thin Film PV Modules Deployed on a Sunny Inland Site

This work aims at analysing the influence of both module temperature and solar spectrum distribution on the outdoor performance of the following thin film technologies: hydrogenated amorphous silicon (a-Si:H), cadmium telluride (CdTe), copper indium gallium selenide sulfide (CIGS), and hydrogenated amorphous silicon/hydrogenated microcrystalline silicon hetero-junction (a-Si:H/μc-Si:H). A 12-month experimental campaign carried out in a sunny inland site in which a module of each one of these technologies was tested and measured outdoors has provided the necessary empirical data. Results show that module temperature exerts a limited influence on the performance of the tested a-Si:H, CdTe, and a-Si:H/μc-Si:H modules. In contrast, the outdoor behaviour of the CIGS module is the most affected by its temperature. Blue-rich spectra enhance the outdoor behaviour of the a-Si:H and a-Si:H/μc-Si:H modules while it is the other way round for the CIGS module. However, the CdTe specimen shows little sensitivity to the solar spectrum distribution. Anyway, spectral effects are scarcely relevant on an annual basis, ranging from gains for the CIGS module (1.5%) to losses for the a-Si:H module (1.0%). However, the seasonal impact of the spectrum shape is more noticeable in these two materials; indeed, spectral issues may cause performance gains or losses of up to some 4% when winter and summer periods are considered.

Analytical transfer equations for the spectral modelling of III–V multi-junction concentrator solar cells

The varying shape of the direct normal irradiance (DNI) spectrum is mainly determined by air mass (AM), aerosol optical depth (AOD) and precipitable water (PW). Unlike some previous studies that aimed at modelling the spectral impact on photovoltaics (PV), a recently published method takes these parameters into account when modelling spectral effects on concentrating PV. A short review of this method is provided initially in this paper. Then, this work presents the results of an empirical validation for a typical lattice-matched 3J GaInP/GaInAs/Ge solar cell during four specific days selected from a wider 3-month experimental campaign. During this period, spectral DNI measurements were recorded at 5-minute intervals and combined with the spectral response of the CPV solar cell considered to calculate measured values of the spectral factor (SF). Results show how predicted values of SF are in close agreement with measured ones as root mean square error (RMSE) values do not exceed 2% for all the days analysed. Further, negligible values of mean bias error (MBE) are obtained. The best results are obtained in days with moderate values of AOD and PW -RMSE around 0.5%- while modelled values of SF get worse -RMSE slightly less than 2%- in days with extreme values of such parameters. Last, the method investigated here yielded a value of RMSE of 0.8%, which is far below 2.3% obtained by applying the other methods for the whole 3-month period under study.

Behavioral data of thin-film single junction amorphous silicon (a-Si) photovoltaic modules under outdoor long term exposure

Four years׳ behavioral data of thin-film single junction amorphous silicon (a-Si) photovoltaic (PV) modules installed in a relatively dry and sunny inland site with a Continental-Mediterranean climate (in the city of Jaén, Spain) are presented in this article. The shared data contributes to clarify how the Light Induced Degradation (LID) impacts the output power generated by the PV array, especially in the first days of exposure under outdoor conditions. Furthermore, a valuable methodology is provided in this data article permitting the assessment of the degradation rate and the stabilization period of the PV modules. Further discussions and interpretations concerning the data shared in this article can be found in the research paper “Characterization of degradation and evaluation of model parameters of amorphous silicon photovoltaic modules under outdoor long term exposure” (Kichou et al., 2016) [1].

An Assessment on the Impact of the Solar Spectrum on Different PV Materials in Sunny Sites by Using Different Time Scales

This chapter is addressed at analyzing how the performance of some photovoltaic (PV) materials is influenced by the solar spectrum distribution according to the months of the year. Spectral responses of four different PV technologies—amorphous silicon, cadmium telluride, copper indium diselenide, and monocrystalline silicon—have been used to develop this study. Spectra and incident global irradiance were scanned at 5-min intervals in two inland sunny sites located in Spain during a 12-month experimental period. Regarding the results, it was concluded that amorphous silicon and cadmium telluride PV modules undergo the highest differences of monthly spectral gains over the year. Much slighter seasonal variations of these gains are perceptible in the other two considered PV technologies. Specifically in the two locations analyzed, spectral gains range from approximately − 12 % (January) to around 2 % (June) for the amorphous silicon (a-Si) PV module while such gains range from values close to 0 % (April to September, inclusive) to values slightly lower than − 2 % (December) for the copper indium diselenide (CIS) and monocrystalline silicon (m-Si) PV module. Prevailing “red-rich” and “blue-rich” spectra in winter and summer, respectively, could explain these results.