A round‐robin proficiency test (RR PT) on thin‐film multi‐junction (MJ) photovoltaic (PV) cells was run between 13 laboratories within the European project CHEETAH. Five encapsulated PV cells were circulated to participants for being tested at Standard Test Conditions (STC). Three cells were a‐Si/μc‐Si tandem PV devices, each of which had a different short‐circuit current ratio between the top junction and the bottom one; the remaining two cells were single‐junction PV devices made with material representative of the individual junctions in the MJ cells. The RR PT's main purpose was to assess the capability of the participating laboratories, in terms of employed facilities and procedures, to test MJ PV devices. Therefore, participants were requested to perform STC measurements of all cells according to their own procedure, which might not include external quantum efficiency measurements. The European Solar Test Installation (ESTI) of the Joint Research Centre (JRC) provided the reference calibrations against which the participants' results are compared. ESTI made also a verification of the cells performance at STC at the end of the RR PT, in order to allow a comparison between the initial stable state at which the cells were calibrated (just before circulation) and the one they had reached at the end of the RR PT. The overall results of the RR PT are here presented and discussed together with some aspects of MJ PV testing that emerged as not adequately applied or largely missing. Their full implementation is expected to improve the consistency of future results.

In order to assess the performance of solar micro-concentrators, specific methods and protocols need to be developed, tested, and applied. In detail, as in conventional concentration modules, one of the fundamental parameters to consider is the efficiency of optical concentrators. In fact, optical concentrators give fundamental information on the current potentially generated from solar microcells that receive the concentrated light radiation. To develop a measurement method for micrometer-size optical components, a suitable optical system was implemented and used. Moreover, the potential application of the printed microstructures in an optical system for solar micro-concentrators was demonstrated.

The results of a measurement intercomparison between eleven European laboratories measuring PV energy relevant parameters are reported. The purpose of the round-robin was to assess the uncertainty analyses of the participating laboratories on c-Si modules and to establish a baseline for the following thin-film round-robin. Alongside the STC measurements, low irradiance conditions (200W/m) and temperature coefficients measurements were performed. The largest measurement deviation from the median at STC was for HIT modules from -3.6% to +2.7% in PMAX, but in agreement with the stated uncertainties of the participants. This was not the case for low irradiance conditions and temperature coefficients measurements with some partners underestimating their uncertainties. Larger deviations from the median from -5% to +3% in PMAX at low irradiance conditions and -6.6% to +18.3% for the PMAX temperature coefficient were observed. The main sources of uncertainties contributing to the spread in measurements were the RC calibration, mismatch factor and capacitive effects at STC and low irradiance conditions as well as the additional light inhomogeneity for the latter. The uncertainty in the junction temperature and the temperature deviation across the module were the major contributors for temperature coefficients measurements.

This work presents various models developed and implemented within the SOPHIA European project in order to thermally characterize PV modules in a rooftop BIPV configuration. Different approaches have been considered, including a linear model, lumped elements models and models that make use of commercial software solvers. The validation of the models performed by comparing the results of simulations with experimental data recorded on a test bench over an entire year is presented and discussed on a seasonal basis. The results have shown that all the models implemented allow achieving a good prediction of the PV modules back surface temperature, with the minimum value of the coefficient of determination R2 around 95% on a yearly basis. Moreover, the influence of season weather conditions and of the incident solar irradiance magnitude on the accuracy of the considered thermal models is highlighted. The major result of the present study is represented by the fact that it has been possible to perform a better thermal characterization of the BIPV module by tuning some of the heat transfer coefficients, such as those relative to the effects of the wind velocity, and to the evaluation of sky temperature. (C) 2017 Elsevier Ltd. All rights reserved.

CHEETAH is an FP7 integrated research project on photovoltaics funded by the European Commission and was initiated by EERA PV. This project is structured into two type of activities: Coordinative and Support actions (CSA) and Joint Research activities (JRA). The CSA focuses on the creation of a long term collaborative platform by developing tools for knowledge sharing, e-learning platforms for training and education, mobility between researchers, efficient use of infrastructures and promoting best practices and standards. The JRA focuses on developing new concepts and technologies for wafer-based crystalline silicon PV (modules with thin cells alt; 100 micron), thin-film PV (advanced light management) and organic PV (very low-cost barriers), resulting in reduced cost of environmentally benign/abundant/non-toxic materials and increased module performance. This paper gives a summary of the main achievements of this project for the two categories of activities.

The electrical ageing of photovoltaic modules during extended damp‐heat tests at different stress levels is investigated for three types of crystalline silicon photovoltaic modules with different backsheets, encapsulants and cell types. Deploying different stress levels allows determination of an equivalent stress dose function, which is a first step towards a lifetime prediction of devices. The derived humidity dose is used to characterise the degradation of power as well as that of the solar cell's equivalent circuit parameters calculated from measured current–voltage characteristics. An application of this to the samples demonstrates different modes in the degradation and thus enables better understanding of the module's underlying ageing mechanisms. The analysis of changes in the solar cell equivalent circuit parameters identified the primary contributors to the power degradation and distinguished the potential ageing mechanism for each types of module investigated in this paper. © 2016 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd. © 2016 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.

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.

FP7-SOPHIA, the European PV Research Infrastructure project coordinated by CEA-INES ended on 31st of January 2015. The project focused on strengthening and optimising the research capabilities of outstanding European Research Infrastructures by pulling together numerous scientists and researchers of more than 48 relevant Research Infrastructures to share a common vision and to conduct efficient and coordinated research work in the field of PV technologies. SOPHi@Webinar is the internal e-learning platform that has organized a set of online courses/seminaries/guest lectures in parallel to more conventional training initiatives held physically. It has also been opened to non-SOPHIA members.

FP7-SOPHIA, the European PV Research Infrastructure project coordinated by CEA-INES ended on 31st of January 2015. The project focused on strengthening and optimising the research capabilities of outstanding European Research Infrastructures by pulling together numerous scientists and researchers of more than 48 relevant Research Infrastructures to share a common vision and to conduct efficient and coordinated research work in the field of PV technologies. SOPHi@Webinar is the internal e-learning platform that has organized a set of online courses/seminaries/guest lectures in parallel to more conventional training initiatives held physically. It has also been opened to non-SOPHIA members.

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.

FP7-CHEETAH is a combined collaborative p roject (CP) and coordination and support action (CSA ) funded under the European Commission’s 7th Framework program and coordinated by ECN, NL with the aims t o solve specific R&D issues and to overcome fragmenta tion of European PV R&D by intensifying the collabo ration between R&D providers and industry to accelerate the industrialization of innovations. The project is a l o tightly linked to the EERA-PV Joint Program. The CHEETAH Know ledge Exchange Area Portal (KEAP), in parallel to t he project web site and other dissemination activities (newsletter, communication, etc), constitutes the pillar of the project to distribute information in a uniform and simple way. It is based on several very efficient ICT procedures by operating from the collection to management of info rmation by dynamic data base matrix: any uploaded i nformation is linked to all others. All interested browsers/re ad rs can have efficient access to any stored data th nks to the utilization of a search engine/query keywords and u ser friendly graphic interfaces. Based on the imple entation of SOPHi@webinar platform, the portal also offers its own e-learning platform. CHEETAH KEAP represents for its peculiarities a majo r breakthrough in the field with highly innovative contents and a substantial improvement in comparison with th e state of the art of knowledge exchange on PV RTD.

The inter-comparability of ageing of organic photovoltaic (OPV) technologies in dark is addressed. Four primary factors that affect the reproducibility of the ageing rate determination and inter-comparison are discussed: production/encapsulation of the samples, current voltage (IV) characterization, testing conditions for ageing and lifetime determination from a decay curve.Results of inter-laboratory ageing studies of roll-to-roll and spin coated samples with correspondingly flexible plastic packaging and glass stored in dark conditions among 7 laboratories are presented. ISOS test conditions, proposed recently as guiding protocols for testing OPV stability, are applied in the study. The reproducibility of the performance versus the production and encapsulation techniques is firstly studied. The results reveal a significant improvement in the reproducibility when going from manual spin coating to roll-to-roll production. Furthermore, the reproducibility of current voltage (IV) measurement and preconditioning (light soaking treatments) are addressed. Additionally, the intercomparison of the degradation rates of the samples aged under three different dark test conditions (ambient, dry/heat, damp heat) reported by different groups are analyzed revealing a reasonable agreement. Finally, a logarithmic diagram for OPV lifetime associated with common time units is proposed that allows conveniently categorizing and intercomparing the stability performance of different samples aged under different test conditions. (C) 2014 Elsevier Ltd. All rights reserved.

Results of the European FP7 Sophia project roundrobinof c-Si module power measurements at STC andlow irradiance and temperature coefficients were used tocalculate annual energy yield at four sites. The deviationin the estimates solely due to the different measurementresults is reported, neglecting the uncertainty in themeteorological data and losses unrelated to theperformed measurements. While minimising thedeviation in Pmax measurements remains the keychallenge, the low irradiance and temperaturecoefficient contributions are shown to be significant.Propagating the measurement deviation in c-Si modulemeasurements would suggest that expanded uncertaintyin energy yield due to module characterization alone canbe as high as ±3-4%.

The results of a measurement intercomparison between eleven European laboratories measuring PV energy relevant parameters are reported. The purpose of the round-robin was to assess the uncertainty analyses of the participating laboratories on c-Si modules and to establish a baseline for the following thin-film round-robin. Alongside the STC measurements, low irradiance conditions (200W/m2) and temperature coefficients measurements were performed. The largest measurement deviation from the median at STC was for HIT modules from -3.6% to +2.7% in PMAX, but in agreement with the stated uncertainties of the participants. This was not the case for low irradiance conditions and temperature coefficients measurements with some partners underestimating their uncertainties. Larger deviations from the median from -5% to +3% in PMAX at low irradiance conditions and -6.6% to +18.3% for the PMAX temperature coefficient were observed. The main sources of uncertainties contributing to the spread in measurements were the RC calibration, mismatch factor and capacitive effects at STC and low irradiance conditions as well as the additional light inhomogeneity for the latter. The uncertainty in the junction temperature and the temperature deviation across the module were the major contributors for temperature coefficients measurements.