The photovoltaic market has recently experienced an enormous expansion, mainly due to the generous Feed-in-Tariffs (FiTs) adopted by many countries. However, in the recent years FiTs have been considerably reduced or even disappeared as their role in the PV deployment has ended. One of the alternatives is the Net-Metering (NEM) policy, which has attracted the interest of stakeholders as it provides a basis for the efficient collaboration between generation and the consumption profiles of the consumer. Currently, there is a lack of a universal policy harmonizing the respective legislations of the E.U. member countries. This paper proposes a novel generalized methodology for the techno-economic assessment of different NEM policies in terms of profitability for the prosumer. The methodology is tested in a formulated case study based on the current NEM policy in Greece. The method proposed uses as inputs the averaged load profiles constructed from real measurements collected from 31 consumers in the Thessaloniki area and evaluated PV production. The current NEM policy and four alternatives are examined, using as additional input the average system marginal prices of the year 2013. The results show that the proposed methodology is capable of evaluating a wide variety of NEM policies and can lead to suggestions for policy adaptation in order to establish a win-win contract between all interested stakeholders.

The outdoor performance monitoring of perovskite modules over 16 weeks is reported. Two different types of active perovskite layers were studied: one type contained formamidinium chloride (FACl) halide additives and the other contained no additives with the main purpose to investigate performance trends during the outdoor exposure of those type of devices. Long-term side-by-side outdoor testing of devices with and without halide additives was not implemented in the past and merits investigation in order to determine the impact of additives on perovskite performance and stability. Although the two types of modules displayed similar initial outdoor performance characteristics, their outdoor performance evolution differed. Different degradation rates between the modules with and without additives were obtained just after field installation. In particular, the modules with additives exhibited higher performance degradation under open-circuit loading conditions between current-voltage (IV) scans. Long-term monitoring of both modules recorded a reduction of the efficiency over the course of the day with subsequent recovery overnight and in many cases during the day. The relative values of performance degradation and overnight recovery were calculated over the timespan of outdoor testing and indicated dominant normalized diurnal performance degradation in one type of modules (without FACl additives) in the range between 15–20% and in the other type of modules (with additives) 5–10%. The dominant normalized performance recovery values found were 25–30% and 5–10%, respectively. Finally, dark lock-in thermography (DLIT) and Raman studies were performed on the exposed devices and revealed differences in hotspot evolution and vibrational modes between the different types of module.

Organic–inorganic hybrid metal halide perovskites are poised to revolutionize the next generation of photovoltaics with their exceptional optoelectronic properties and compatibility with low-cost and large-scale fabrication methods. Since perovskite tends to degrade over short time intervals due to various parameters (oxygen, humidity, light, and temperature), advanced characterization methods are needed to understand their degradation mechanisms. In this context, investigation of the electrical and optoelectronic properties of several perovskite mini-modules was performed by means of photo- and electroluminescence imaging as well as Dark Lock-In Thermography methods. Current–voltage curves at periodic time intervals and External Quantum Efficiency measurements were implemented alongside other measurements to reveal correlations between the electrical and radiative properties of the solar cells. The different imaging techniques used in this study reveal the changes in radiative emission processes and how those are correlated with performance. Alongside the indoor optoelectronic characterization of perovskite reference samples, the outdoor monitoring of two perovskite modules of the same structure for 23 weeks is reported. Significant performance degradation is presented outdoors from the first week of testing for both samples under test. The evolution of the major electrical characteristics of the mini-modules and the diurnal changes were studied in detail. Finally, dark storage recovery studies after outdoor exposure were implemented to investigate changes in the major electrical parameters.