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32nd European Photovoltaic Solar Energy Conference and Exhibition; 1385-1389, The aim of this work is to report the results of the main characterization activities carried out on the ECOSOLE HCPV prototypal plant realized by BECAR s.r.l. and installed at ENEA Research Center located at Portici in the south of Italy. After a detailed description of the system main components, the experimental results regarding the module characterizations, the tracker accuracy, the system optical acceptance, and the module temperature survey are detailed. The second part of the paper is focused on the explanation of the performance analysis carried out on the basis of the data collected during the first three months of operation. Particular attention has been paid to the performance comparison of the two sub-arrays of the plant: the first one is realized with module using each one its-own inverter, and the second one is realized with a classic centralized inverter solution. At the end, a procedure for a detailed losses analysis is reported and the results obtained for a whole sunny day are explained.

31st European Photovoltaic Solar Energy Conference and Exhibition; 1487-1491, ECOSOLE is an European collaborative Project [1] started in August 2012 that involves several industrial and institutional partners with the aim to develop a complete and innovative concentrating photovoltaic system. During the first two years of activity, many specific components as cells, optics, modules and tracker have been designed and developed. This work reports the description of these devices and the main results of the characterization campaigns carried out both indoor and outdoor conditions, in order to define their technical features as well as their performances. Particular attention has been paid to the investigation on the components reliability which is a crucial point for the CPV technology diffusion.

Starting on June 2011, NGCPV has been the first coordinated project between the European Commission and Japanese NEDO in order to advance in the science and technology of concentrator photovoltaics (CPV). Research has covered all relevant areas in CPV, from solar cells to complete systems, including multijunction solar cells, novel solar cell concepts utilizing nanostructures, advanced optics and modules, thermal management, reliability and modeling at all the stages of the CPV chain, rating and round robin schemes and the development of characterization tools for cells, modules and systems (outdoor and indoor). Ending in November 2014, the NGCPV project has attained some remarkable results, such as the manufacturing of a 44.4% world record efficiency triple junction solar cell (by Sharp Corp.) and the development of a 15 kW CPV system (by Daido, BSQ and UPM) with a DC efficiency of 28% under CSOC, which is the highest reported in the world at system level. In this paper we summarize these and other relevant results concerning project activities such as the investigation of novel buffers for growing III-V materials on silicon, novel ~1eV materials for manufacturing quad-junction solar cells, the development of accurate models to forecast the electricity production in CPV plants and novel advanced optical designs for CPV modules, among others.

29th European Photovoltaic Solar Energy Conference and Exhibition; 2119-2124, The use of light concentrator systems has been proved to be an effective means of reducing the electricity costs produced by photovoltaics; in fact with this technology the area of the photovoltaic cell used is reduced, compared with a flat-photovoltaic application, thanks to the introduction of less expensive lenses and mirrors. The aim of this paper is the description and realization of several outdoor measurement apparatuses for an overall outdoor characterization of cells and lenses for photovoltaic concentration systems; in this way we can determine the electrical and the optical characteristics of concentration systems using as light source directly the sun light. Therefore the problem to reproduce a light flux over extensive areas with the same spatial divergence of the sun light, very important problem to face for indoor measurement apparatuses, it is overcome.

28th European Photovoltaic Solar Energy Conference and Exhibition; 664-667, This work deals with the thermal analysis of the heat sink relative to a novel high-concentrating photovoltaic system developed in the framework of the European project ECOSOLE. The thermal analysis has been performed taking into consideration two different conditions, namely the worst condition that occurs when the module doesn’t produce energy and the tracker is in perfect alignment with the sun, and the design conditions with the module operating in its MPPT. 3D numerical simulations have been performed using the commercial software Comsol Multiphysics in order to evaluate the temperatures maps relative to the cell and the heat sink in both the considered conditions. Furthermore, the thermo-fluid-dynamics of the air inside and around the HCPV module frame have been characterized by means of 3D numerical simulation performed using the commercial software ANSYS Fluent.

27th European Photovoltaic Solar Energy Conference and Exhibition; 128-133, APOLLON is an European collaborative Project of the Seven Framework program started in July 2008 involving SMEs, industries and several research Institutions with the aim to develop economical competitive Point focus and Mirror Based Spectra Splitting photovoltaic concentrating modules (systems). In this contest, a point focus optical system has been developed by ENEA in close collaboration with SE SRTIIE and CRP. It is composed by a primary refractive optic and a reflective secondary element; the target concentration ratio is about of 750 X. The primary optic is a refractive lens having an hybrid Fresnel-prismatic shape designed by ENEA and realized by CRP using the injection-compression molding process. The Secondary Optical Element is a truncated cone realized by SE SRTIIE with a commercial reflective sheet supplied by Alanod and named “Miro high reflective 95”. The optical system has been tested both in indoor and in outdoor conditions at the ENEA Research Center Laboratories obtaining excellent optical performance. In particular, an optical efficiency of 81% with ±0,9° acceptance angle have been measured.

26th European Photovoltaic Solar Energy Conference and Exhibition; 702-706, In the framework of the cooperation between ENEA and Pirelli, an innovative HCPV - High Concentration Photovoltaic System - prototype developed by Pirelli has been installed at ENEA-Portici, Italy. The plant includes an aerodynamic profile solar tracker, resistant to strong wind, equipped with 40 HCPV modules, based on the concentration technology developed by Pirelli. The whole system has been developed according to industrial cost considerations; the modules have been designed for being assembled by means of automatic process and components have been developed for being manufactured in the framework of automotive industries. The optical system is a Fresnel-Kohler type developed in the framework of cooperation with LPI (Light Prescription Innovators) a leading company in optical design for CPV system based in Madrid, Spain. It assures optimal performances in terms of efficiency, optical flux homogeneity and acceptance angle. Moreover, it is robust in terms of assembly tolerances. The optical system focuses radiation with a geometrical concentration factor of 576 on a 5.5mm-side III-V solar cell supplied by Emcore. Each module comprises 48 single units, electrically connected in two separated series. Based on optically active area, the efficiency of the module is as high as 28%, with typical efficiency values of 26.5%. Typical module acceptance angle of 1.2° is measured. Nominal module power @850W/m2, 25°C, is 167Wp. Modules have been installed on Pirelli solar tracker, developed according to Eurocodes standards for civil structures; they are connected in 4 electrical sections for assuring a high degree of versatility. Nominal system power is 6.7 kWp. In real operations system DC efficiency as high as 25% has been reached. Moreover, system acceptance angle of about 0.8° has been measured. In the present work, results of system field tests are presented and discussed, as well as measurements of some significant performance of components.

26th European Photovoltaic Solar Energy Conference and Exhibition; 137-144, An overview of the achievements accomplished in the first phase of the APOLLON project, related to the optimisation of point focus (PF) and mirror based spectra splitting systems (MBS3) is presented as well as some preliminary results on the proposed innovative Concentrating Photovotaic (CPV) technologies (intelligent CPV modules).

25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 910-912, Key issues for the wide diffusion of compact devices for sunlight exploitation are both reduction of costs and increase in efficiency. A promising device should reach a good tradeoff between these two requirements. We studied the possibility to approximate a Compound Parabolic Concentrator (CPC) by simpler shapes, while maintaining as much as possible the level of sunlight collection efficiency. We investigated several approximation approaches, with a common characteristic being the use of truncated conic surfaces that are easy to optically manufacture by cheap and widely available machining techniques. All the considered configurations were compared and quantitatively evaluated using lighting simulation software (Lambda Research Trace-Pro), considering the collected power of obtained sunlight distributions.

25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 994-998, Sunlight concentration onto photovoltaic cells can contribute to reduce the total system cost of photovoltaic plants. The aim of this work is the development of a low cost photovoltaic concentration system design for building integration; to reduce the cost of these systems, you can use concentration PV cells coming from conventional systems and modified to work in concentration. This module has been developed around ENEA concentration cell, realized in ENEA’s laboratory in Portici (Italy), and based on c-Si technology. Starting from characteristic data obtained by experimental apparatus or by simulation programs, and using an empirical model based on this information, an optimum combination of the different structures involved in the concentration process has been determined. This optimization procedure is based on the minimization of the energy cost determined for a particular geographical site (Real Reporting Conditions). Finally a mock-up module based on this technology has been assembled and characterized outdoors.

24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 3363-3366, Heterojunction PV modules with intrinsic thin layer have been proved to be very well performing and they are, at the moment, among the best modules available on the market in terms of efficiency (about 16%); but due to the presence of the thin film layer an issue about their reliability rises. ENEA (Italian National Agency for New Technologies, the Energy and the Environment) installed in the year 2006 a double axis Photovoltaic Plant made of Sanyo Heterojunction panels with Intrinsic Thin layer (HIP-200NHE1) at its facility located in the Research Centre of Portici near to Naples, in Southern Italy. The PV modules are made of a thin monocrystalline silicon wafer sandwiched within ultra-thin amorphous silicon layers. The aim of this paper is to prove the PV modules endurance to maintain the energetic performances during their working time. To prove this a detailed analysis, by means of indoor and outdoor tests, has been carried out, aimed to evaluate the PV module potential performance degradation. The PV plant performance data have been collected during two working years (July 2006- June 2008) and analyzed. Besides one module has been subjected to a very severe artificial accelerated ageing sequence.

24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 4052-4056, Within the operating program aimed to on-site power generation, launched by Regione Campania ENEA (Italian National Agency for New Technologies, the Energy and the Environment) realized a double axis photovoltaic plant feeding an electrolyser for the hydrogen production. The facility is located in the Research Centre of Portici near to Naples, in southern Italy. The PV generator is composed of 4 standard units of 2.4kWp each for a total power of 9.6kWp at STC. The PV array includes 12 modules Sanyo Heterojunction with Intrinsic Thin layer HIP-200NHE1 mounted on the double axis sun Deger Tracker 1600EL. The 10kW alkaline electrolyser for hydrogen production, operating at atmospheric pressure, has been used. The focus of this work is to illustrate the PV plant energetic performance during two working years (July 2006 - June 2008) performing, also, a comparative analysis among PV installations of different kind, like flat system, single axis tracking systems. With regard to this a technical and economical analysis aimed to evaluate the energetic advantages due to the use of tracking PV technology, especially for installation sites located in southern Italy, has been carried out.

24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 777-781, Since 2002 ENEA (Italian National Agency for New Technologies, the Energy and the Environment) has been involved on PV Concentrator Technology (CPV), by way of PhoCUS (Photovoltaic Concentrators to Utility Scale) Project. The Project aimed to the development of a low-cost photovoltaic concentrators technology using Single cSi Junction solar cells working under a medium concentration ratio. On the other hand the potentiality of CPV systems to reach efficiency value higher than 30% is related to the utilization of the solar cell Multi-Junction (MJ) technology originally developed for space application, too. ENEA has recently been involved in the APOLLON project (Multi APprOach for high efficiency integrated and inteLLigent cONcentrating PV modules Systems), funded by the European Union for the development of new material and improvement of existing technologies. The goal of the project is to increase concentrating cell and module efficiency, stability and lifetime and to achieve a suitable cost-effective condition, in close cooperation with many European partners and companies. In this scenario ENEA realized a set of several C-Modules, based on existing PhoCUS PV-C technology and on the use of commercial MJ and SJ solar cells, in order to promptly assure opportunities from the first stage of APOLLON Project, to analyze the assembling techniques used for two both kinds of receivers (working under different concentration ratio) evaluating the influence of passive cooling and thermal behaviour, misalignments receiver-lens, and the manufacturing process automation. Further efforts were also put on the ground by ENEA concerning the development of outdoor facilities at the aim to carry out photovoltaic performance evaluation and objective comparison about different technological solutions.

23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 448-452, All concentrator devices, both photovoltaic and thermal, are designed to collect only some predetermined direct portion of the solar radiation; so, the correct measurement of the direct solar radiation incident on a C-system is requested to calculate properly its efficiency. The focus of this paper is to describe a novel, and simple, method to measure the CSR (CircumSolar Ratio) [1-5] and a measurement apparatus, put under Italian patent [6], developed at this aim. It is composed of a lens, a diaphragm on the lens focus, a measurement device (e.g. a photodiode, a thermopile, etc) on axis with the lens, everyone assembled on a stiff mechanical support. The whole system is installed on a solar tracker so that the perfect alignment between lens and solar radiation is guaranteed. Thanks to optical simulations we have concluded that, when a suitable achromatic lens is used, a good one-to-one correspondence exists - from practical point of view - between the diaphragm aperture and the maximum angular divergence of the solar radiation collected by the instrument on the detector. So, in principle, increasing the diaphragm aperture, the solar irradiances corresponding to the growing values of solar radiation angular divergences can be measured. Then, on the basis of the measurements of the solar divergence yearly average value, it is possible to understand when a C-system works at its best for a fixed site in connection to the CSR measured value.

23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 914-919, The Photovoltaic Concentrator technology is considered a promising alternative option to PV-flat to overcome the present day barriers in terms of material shortage and costs. Relevance was given by ENEA through the PhoCUS project having the aim to develop a new technology able to realize a monolytic low-cost photovoltaic module suitable to work under medium concentration (200X). Several technical problems were faced and overcome about the development of the solar cells, the system housing integrating optics and receivers, the realization of the lenses and heat spreaders and the mechanical-thermal and electrical performance modelling. In order to meet the low cost requirement a large use of conventional materials and components together with manufacturing and assembling techniques addressed to a cheap full automation have been adopted in cooperation with national industrial operators. The effort made has brought to file many patents relating novel solutions used in Phocus C-module. The final product meeting the design specification was obtained.

Starting on June 2011, NGCPV is the first project funded jointly between the European Commission (EC) and the New Energy and Industrial Technology Development Organization (NEDO) of Japan to research on new generation concentration photovoltaics (CPV). The Project, through a collaborative research between seven European and nine Japanese leading research centers in the field of CPV, aims at lowering the cost of the CPVproduced photovoltaic kWh down to 5 ?cents. The main objective of the project is to improve the present concentrator cell, module and system efficiency, as well as developing advanced characterization tools for CPV components and systems. As particular targets, the project aims at achieving a cell efficiency of at least 45% and a CPV module with an efficiency greater than 35%. This paper describes the R&D activities that are being carried out within the NGCPV project and summarizes some of the most relevant results that have already been attained, for instance: the manufacturing of a 44.4% world record efficiency triple junction solar cell (by Sharp Corp.) and the installation of a 50 kWp experimental CPV plant in Spain, which will be used to obtain accurate forecasts of the energy produced at system level.

28th European Photovoltaic Solar Energy Conference and Exhibition; 88-93, Starting on June 2011, NGCPV is the first project funded jointly between the European Commission (EC) and the New Energy and Industrial Technology Development Organization (NEDO) of Japan to research on new generation concentration photovoltaics (CPV). The Project, through a collaborative research between seven European and nine Japanese leading research centers in the field of CPV, aims at lowering the cost of the CPV-produced photovoltaic kWh down to 5 €cents. The main objective of the project is to improve the present concentrator cell, module and system efficiency, as well as developing advanced characterization tools for CPV components and systems. As particular targets, the project aims at achieving a cell efficiency of at least 45% and a CPV module with an efficiency greater than 35%. This paper describes the R&D activities that are being carried out within the NGCPV project and summarizes some of the most relevant results that have already been attained, for instance: the manufacturing of a 44.4% world record efficiency triple junction solar cell (by Sharp Corp.) and the installation of a 50 kWp experimental CPV plant in Spain, which will be used to obtain accurate forecasts of the energy produced at system level.

31st European Photovoltaic Solar Energy Conference and Exhibition; 1384-1391, Starting on June 2011, NGCPV has been the first coordinated project between the European Commission and Japanese NEDO in order to advance in the science and technology of concentrator photovoltaics (CPV). Research has covered all relevant areas in CPV, from solar cells to complete systems, including multijunction solar cells, novel solar cell concepts utilizing nanostructures, advanced optics and modules, thermal management, reliability and modeling at all the stages of the CPV chain, rating and round robin schemes and the development of characterization tools for cells, modules and systems (outdoor and indoor). Ending in November 2014, the NGCPV project has attained some remarkable results, such as the manufacturing of a 44.4% world record efficiency triple junction solar cell (by Sharp Corp.) and the development of a 15 kW CPV system (by Daido, BSQ and UPM) with a DC efficiency of 28% under CSOC, which is the highest reported in the world at system level. In this paper we summarize these and other relevant results concerning project activities such as the investigation of novel buffers for growing III-V materials on silicon, novel ~1eV materials for manufacturing quad-junction solar cells, the development of accurate models to forecast the electricity production in CPV plants and novel advanced optical designs for CPV modules, among others.

The fast development of the CPV technology requires the use of photovoltaic cells more and more small and with very high conversion efficiency: optics and modules are designed to reach nominal concentration ratio up to 1000X [1]. In this technological framework, it is very important to test the cell performances using a laboratory equipment, as a solar simulator, able to generate on the cell an irradiance corresponding to the real working conditions. In the market, it is possible to buy several systems designed and produced by specialized Companies or Research Institutes able to make a reliable cell characterization. Unfortunately, these systems are very expensive, because they are built with components specially developed for this purpose. In this paper the authors present a solar simulator for concentrating photovoltaic cells realized with cheap standard components normally used for other scopes. The results is a prototypal system having a cost significantly lower than the commercial solar simulators. Main disadvantage of this approach is that a good power density uniformity on the measurement point is reached only for small size cells (diameter less than 4mm). © 2018 Author(s).

This paper reports the results of a performance analysis carried out by ENEA on a CPV system, produced by BECAR srl within a European collaborative Project named ECOSOLE, and installed at ENEA Research Center of Portici. Modules degradation after two operation years has been evaluated by means of detailed characterizations; tracker system accuracy has been monitored using a specific opto-electronic device. System performances during the period has been analysed based on the production and weather data: a deep performance analysis has been carried out in order to quantify the main losses causes in DC side. The behaviours of the two sub-fields of the system, the first one realized with one centralized inverter for 16 modules and the second one with 16 modules having each one its own inverter, have been compared from technical and economical point of view.This paper reports the results of a performance analysis carried out by ENEA on a CPV system, produced by BECAR srl within a European collaborative Project named ECOSOLE, and installed at ENEA Research Center of Portici. Modules degradation after two operation years has been evaluated by means of detailed characterizations; tracker system accuracy has been monitored using a specific opto-electronic device. System performances during the period has been analysed based on the production and weather data: a deep performance analysis has been carried out in order to quantify the main losses causes in DC side. The behaviours of the two sub-fields of the system, the first one realized with one centralized inverter for 16 modules and the second one with 16 modules having each one its own inverter, have been compared from technical and economical point of view.

The results of three CPV module round robins are presented. Ten test labs around the world participated to the round robins in total. Each round robin used a different CPV module technology (Daido Steel, Soitec, Suncore). The data gathered at the test labs was used to test CSOC power rating procedures as basis for the IEC draft standard 62670-3. The deviation between the minimum and the maximum power output rated at the test labs was in average 4.4 % with a standard deviation of 1.8 %abs. This underlines that power ratings or CPV modules are reliable and reproducible. © 2016, American Institute of Physics Inc. All rights reserved.