• Energy Research

This paper presents an assessment and evaluation of the costs of operation and maintenance (O&M) in a real PV rural electrification (PVRE) programme, with the aim of characterizing its costs structure. Based on the extracted data of the 5-years operational costs of a private operator, the programme has been analyzed to take out the most relevant costs involved in the O&M phase as well as the comparative appraisal between the 3 main activities: installation, O&M and management. Through this study we try to answer to the new challenge of decentralized rural electrification based on larger programmes (with tens of thousands of SHSs) and longer maintenance and operation periods (at least 10 years).

Large-power PV irrigation systems (PVIS) from 40 kWp to 1 MWp are increasingly being introduced onto the market since the main technical barriers have been removed and some real-scale demonstrators have shown cost savings up to 80% when compared with the electricity costs from the grid or diesel generators. The electricity compatibility between the PV generator and the frequency converter limits the number of PV modules in series to keep the PV generator voltage below the maximum input voltage of the frequency converter. This limitation can produce losses in terms of PV production and water pumped. As the maximum voltage delivered by the PV generator depends, among others, on the solar cell temperature, some electronic devices are being offered in the market to change the number of PV modules in series depending on this temperature, but they are complex and reduce the reliability of the system. This complexity is not justified because an in-depth analysis of the actual impact of these losses has never been carried out. This paper analyses and quantifies these PV energy losses for the two main applications in the market (pumping to a water pool at a variable frequency, and direct pumping to the irrigation network at constant power) which have different mechanisms of losses, and for locations with different typical meteorological years. The results show that, in the case of pumping to a water pool, the losses are irrelevant if the maximum yearly mean ambient temperature of the location is less than 21.5 °C and the voltage required by the pump is less than 568 V. In the case of constant power pumping, the losses are irrelevant if the mentioned temperature is less than 25.8 °C and the grid voltage is less than 587 V. In the rest of the cases, the losses are minimized just adding one more PV module in series. As a result, a general methodology to help designers selecting the number of PV modules in series in PV irrigation systems is presented.

This paper presents the experience of a PV pumping project being carried-out in the South of Morocco since 1997. At present, the project has reached 18 villages, affecting 15 000 people. Total involved photovoltaic power is 46 kWp, and the total volume of pumped water since the installation of the systems approaches 0.7 × 106 m3. About half the PV systems are based on dedicated inverters, while the rest are based on standard frequency drivers. Both perform very similarly in terms of both efficiency and reliability. Wells have been selected to provide good water taste, and pumped water is distributed to all the individual houses. Average daily water consumption in summer varies from 13 to 50 litres per person depending on ease of water access and ‚urban proximity’. The maintenance infrastructure is based on an agreement between the European supplier company and a local NGO, which is in charge of all the local organizations. Copyright © 2005 John Wiley & Sons, Ltd.

Stand-alone large-power PV irrigation systems without batteries is a recent innovation. This means that their design has not yet reached maturity and there are no experimental data about their performance available. This paper is a contribution, on the one hand, to the systematic tuning of the control of this type of systems and, on the other hand, to the knowledge of their experimental performance data.A systematic Proportional, Integral and Derivative (PID) control tuning method for frequency converters is proposed, based on the application of the Approximate M−constrained Integral Gain Optimisation (AMIGO) design rules to the frequency response tuning method, and applied to two PV irrigation systems, located respectively in Villena and Aldeanueva de Ebro, Spain, that had a “conservative” tuning by means of an experimental trial and error method.To check the goodness of this systematic tuning, the experimental performance of both systems has been evaluated from 2017 to 2021. New indices have been proposed to assess both the robustness of the system to PV power fluctuations (the “Number of abrupt stops” and the “Passing-cloud resistance ratio”) and the performance (by factoring the traditional Performance Ratio (PR) to determine the influence of different factors external to the system). Results show that the percentage of abrupt stops improves from 40% and 39.8% in each PV irrigation system prior to systematic tuning to 7.3% and 1.3% after tuning; the passing cloud ratio increases from 65% and 79% to 97.9% and 99.8% and the PR from 61.4% and 60% to 65.7% and 64.7%.

Abstract The fault detection applied to a large amount of small distributed PV systems needs to be simple, cost-effective, and reliable. This work presents a fault detection procedure applied to distributed PV system fleets, based on a novel performance indicator, designated as Performance to Peers (P2P), that can be constructed on the sole basis of the comparison of the energy production data of several neighboring PV systems. This article explains how to construct this performance indicator and how to use it to carry out automatic fault detections. This fault detection procedure has been developed in the context of the performance analysis carried out on approximately 6000 PV installations located in Europe, and it is illustrated and discussed through real application cases. The P2P has been shown to be more stable than the Performance Ratio (PR), in particular in the presence of sub-par metadata on the PV systems, and it thus constitutes a more robust performance indicator for fault detection. The stability of P2P is characterized by an Absolute Median Deviation (MAD) that is typically of 10% for hourly data and 5% for daily data. The application of P2P to fault diagnosis is illustrated on four categories of faults that are among the most frequently observed on PV systems. The main limitations of this novel methodology are discussed, and several future lines of research are suggested.

Abstract PV pump manufacturers usually provide standardized graphic tools relating water output with PV array power, under given radiation conditions and for constant pumping head. This paper proposes a simple procedure allowing the use of such graphics for the design of boreholes showing significant water level variations with the water flow rate, which lead to important pumping head variations during the day. The procedure requires a knowledge of three parameters widely used for borehole characterization: ‘static level’, ‘dynamic level’ and ‘maximum flow rate’, and is based on a very simple analytical description of results from a simulation exercise.

The main objective of this paper is to review the state of the art of residential PV systems in France. This is done analyzing the operational data of 6868 installations. Three main questions are posed. How much energy do they produce? What level of performance is associated to their production? Which are the key parameters that most influence their quality? During the year 2010, the PV systems in France have produced a mean annual energy of 1163 kWh/kWp. As a whole, the orientation of PV generators causes energy productions to be some 7% inferior to optimally oriented PV systems. The mean Performance Ratio is 76% and the mean Performance Index is 85%. That is to say, the energy produced by a typical PV system in France is 15% inferior to the energy produced by a very high quality PV system. On average, the real power of the PV modules falls 4.9% below its corresponding nominal power announced on the manufacturer's datasheet. A brief analysis by PV modules technology has led to relevant observations about two technologies in particular. On the one hand, the PV systems equipped with heterojunction with intrinsic thin layer (HIT) modules show performances higher than average. On the other hand, the systems equipped with the copper indium (di)selenide (CIS) modules show a real power that is 16% lower than their nominal value.

This paper presents a description of an open-source simulation tool (features, models and calculation procedures) that has been developed under the support of the European project called PVCROPS. The main advantage of this tool is that it uses as input just parameters guaranteed by the manufacturers of the different components of a PV plant. This way, it can be used in contractual frameworks to establish the expected energy yield of a PV plant, to check the actual performance of the PV plant with quality contractual procedures linked to SISIFO, and to assign responsibilities in the case of underperformance. The tool provides, among other simulation results, the energy yield, the analysis and breakdown of energy losses, and financial analysis. Furthermore the software can generate a technical report with the results obtained in the simulation. 31st European Photovoltaic Solar Energy Conference and Exhibition; 2190-2192