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Three key geographical zones—the Euro area, Japan and the USA—are promoting the use of grid‐connected PV through attractive financial support programmes. After a short introduction to the financial analysis of PV grid‐connected systems, this paper presents some time‐saving charts and tables intended to assess the profitability of such PV systems in respect of some of the economic measures of these programmes. These easy‐to‐use tools are addressed to PV designers and investors to help them assess their investment from an exclusively economic point of view. Decision‐makers in the developed countries may also find them of value in planning their PV support measures. Some examples demonstrate how to use these tools, taking into account different available incentives and economic forecasts. Copyright © 2002 John Wiley & Sons, Ltd.

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The Guidelines for the Assessment of Photovoltaic Plants provided by the Joint Research Centre (JRC) and the International Standard IEC 61724 recommend procedures for the analysis of monitored data to asses the overall performance of photovoltaic (PV) systems. However, the latter do not provide a well adapted method for the analysis of stand-alone photovoltaic systems (SAPV) with charge regulators without maximum power point tracker (MPPT). In this way, the IDEA Research Group has developed a new method that improves the analysis performance of these kinds of systems. Moreover, it has been validated an expression that compromises simplicity and accuracy when estimating the array potential in this kind of systems. SAPV system monitoring and performance analysis from monitored data are of great interest to engineers both for detecting a system malfunction and for optimizing the design of future SAPV system. In this way, this paper introduces an online monitoring system in real time for SAPV applications where the monitored data are processed in order to provide an analysis of system performance. The latter, together with the monitored data, are displayed on a graphical user interface using a virtual instrument (VI) developed in LABVIEW®. Furthermore, the collected and monitored data can be shown in a website where an external user can see the daily evolution of all monitored and derived parameters. At present, three different SAPV systems, installed in the Polytechnic School of University of Jaén, are being monitorized and the collected data are being published online in real time. Moreover, a performance analysis of these stand-alone photovoltaic systems considering both IEC 61724 and the IDEA Method is also offered. These three systems use the charge regulators more widespread in the market. Systems #1 and #2 use pulse width modulation (PWM) charge regulators, (a series and a shunt regulator, respectively), meanwhile System #3 has a charge regulator with MPPT. This website provides a tool that can be used not only for educational purposes in order to illustrate the operation of this kind of systems but it can also show the scientific and engineering community the main features of the system performance analysis methods mentioned above. Furthermore, it allows an external user to download the monitored and analysis data to make its own offline analysis. These files comply with the format proposed in the standard IEC 61724. The SAPV system monitoring website is now available for public viewing on the University of Jaén. (http://voltio.ujaen.es/sfa/index.html).

Pulse width modulated (PWM) charge regulators are frequently used in stand alone photovoltaic (SAPV) systems. Once the battery has reached the regulating voltage, these electronic devices provide current and voltage pulses to regulate the charge current to the battery. This kind of signals implies rapid variation in the variables and may provide, when being monitored, and if some special considerations are not taken into account, an erroneous measurement of the array output current, the array output voltage and the current to storage. Moreover, this inappropriate monitoring will affect not only to these monitored variables but also may spread over the array output power and most of the derived parameters, providing a mistaken system performance analysis from monitored data. In this way, this paper focus on the different issues that can arise when monitoring the parameters mentioned above in SAPV systems with PWM charge regulators. A comparative study of the two types of sensors (shunt and hall-effect transducer) that can be used to capture either the array output current or the current to storage will be developed. Moreover, it is intended to provide easy monitoring procedures to collect the array output and voltage, the current to storage and the array output power as these variables are the more sensitive to the use of PWM charge regulators. These monitoring requirements may be appropriate under field conditions and may become cost-effective. The solutions given here intends to avoid the complex monitoring system and the high computational cost that may require a simultaneous sampling mode at a relative high sampling frequency to obtain an appropriate monitoring for the modulated signals in SAPV systems with PWM charge regulators.