Global energy demand and environmental concerns are the driving force for use of alternative, sustainable, and clean energy sources. Solar energy is the inexhaustible and CO2-emission-free energy source worldwide. The Sun provides 1.4 � 10 5 TW power as received on the surface of the Earth and about 3.6 � 10 4 TW of this power is usable. In 2012, world power consumption was 17 TW, which is less than 3.6 � 10 4 TW. Photovoltaic (PV) cells are the basic element for converting solar energy into electricity. PV cell technologies, energy conversion efficiency, economic analysis, energy policies, environmental impact, various applications, prospects, and progress have been comprehensively reviewed and presented in this paper. This work compiles the latest literature (i.e. journal articles, conference proceedings, and reports, among others) on PV power generation, economic analysis, environmental impact, and policies to increase public awareness. From the review, it was found that PV is an easy way to capture solar energy where PV based power generation has also rapidly increased.

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Global Prospects, Progress, Policies and Environmental Impact of Solar Photovoltaic Power Generation

Extensive worldwide validation and climate sensitivity analysis of direct irradiance predictions from 1-min global irradiance

The main contribution of this paper is to present a new set of approximate analytical solutions for the parameters of a photovoltaic (PV) five-parameter double-diode model that can be used as initial values for the numerical solutions based on the Newton-Raphson method. The proposed formulations are developed based on only the limited information given by the PV manufacturers, i.e., the open-circuit voltage ( Voc), the short circuit current ( Isc), and the current and voltage at the maximum power point (Im and Vm). Compared with the existing techniques that require the entire experimental I-V curve or additional information such as the slope of the I-V curves of the open circuit and the short circuit points, the proposed technique is quite independent of these additional data, and, it is therefore, a low cost and fast parameter extraction method. The accuracy of the theoretical I-V curves is evaluated through the comparison of the simulation results and experimental data. The results of the application of the proposed technique to different PV modules show the accuracy and validity of the proposed analytical-numerical method.

On the Parameter Extraction of a Five-Parameter Double-Diode Model of Photovoltaic Cells and Modules

A simulation model for modeling photovoltaic (PV) system power generation and performance prediction is described in this paper. First, a comprehensive literature review of simulation models for PV devices and determination methods was conducted. The well-known five-parameter model was selected for the present study, and solved using a novel combination technique which integrated an algebraic simultaneous calculation of the parameters at standard test conditions (STC) with an analytical determination of the parameters under real operating conditions. In addition, the simulation performance of the model was compared with other models, and further validated by outdoor tests, which indicate that the proposed model fits well the entire set of experimental field test I–V curves of the PV module, especially at the characteristic points. After validation, this model was employed to predict the PV system power output under real conditions. The results show that the predictions agree very well with the PV plant field collected data. Thus, the operating performance of a standalone PV system located on a remote island in Hong Kong has been further evaluated with the aid of this model. It is found that the PV array power output is restricted by the status of the battery bank. This research demonstrates that the PV simulation model developed during the study is simple, but very helpful to PV system engineers in understanding the I–V curves and for accurately predicting PV system power production under outdoor conditions.

Solar photovoltaic system modeling and performance prediction

Preliminary assessment of a small-scale rooftop PV-grid tied in Norwegian climatic conditions

Contrary to intuition, solar irradiance peaks at partially cloudy conditions. Clouds can boost sunlight by over 1.5 times, even at high latitudes. Depending on cloud velocity, the bursts last from seconds to minutes. Measuring irradiance on a tilted surface with 10-ms resolution allows for a detailed study of such events in Southern Norway, almost at sea level. All monthly maxima from April through September 2011 exceeded 1300 W/m2. The slow sensor registered an annual maximum of 1413 W/m2, while the fast sensor's range was found insufficient. A burst reaching 1528 W/m2 was registered in June 2012. Near the Equator, bursts exceeding 1800 W/m2 have been observed. These numbers are striking since the extraterrestrial solar irradiance peaks in January at about 1400 W/m2. The phenomenon is attributed mainly to forward scattering of light in optically thin clouds (adjacent to the sun), which is much stronger for angles within 5° around the solar disk.

Overirradiance (Cloud Enhancement) Events at High Latitudes

A qualitative examination of performance and energy yield of photovoltaic modules in southern Norway

A new analytical solar cell I—V curve model

This paper presents an improved method to extract physically meaningful parameters from outdoor I-V data of polycrystalline-Si PV modules. The two-diode model of a PV cell is adapted for modules. A novel algorithm is devised to estimate the series resistance from I-V data sets. The ideality factor and the reverse saturation current of the diffusion diodes are then calculated from partially linear semi-logarithmic plots. The complexity and ambiguity typical for non-linear curve fitting are thus avoided. The method is applied to outdoor I-V curves from polycrystalline-Si modules, and preliminary results are presented. A new definition of the local ideality factor is introduced. It compensates for the series-resistance effect at higher voltages, such that a constant ideality factor is obtained for polycrystalline-Si modules in this range of voltages.

Georgi Hristov Yordanov

Papers

Overirradiance (Cloud Enhancement) Events at High Latitudes

A qualitative examination of performance and energy yield of photovoltaic modules in southern Norway

A new analytical solar cell I—V curve model

Two-Diode Model Revisited: Parameters Extraction from Semi-Log Plots of I-V Data

Extreme overirradiance events in Norway: 1.6 suns measured close to 60°N