Global electricity demand is constantly growing, making the utilization of solar and wind energy sources, which also reduces negative environmental effects, more and more important. These variable energy sources have an increasing role in the global energy mix, including generating capacity. Therefore, the need for energy storage in electricity networks is becoming increasingly important. This paper presents the challenges of European variable renewable energy integration in terms of the power capacity and energy capacity of stationary storage technologies. In this research, the sustainable transition, distributed generation, and global climate action scenarios of the European Network of Transmission System Operators for 2040 were examined. The article introduces and explains the feasibility of the European variable renewable energy electricity generation targets and the theoretical maximum related to the 2040 scenarios. It also explains the determination of the storage fractions and power capacity in a new context. The aim is to clarify whether it is possible to achieve the European variable renewable energy integration targets considering the technology-specific storage aspects. According to the results, energy storage market developments and regulations which motivate the increased use of stationary energy storage systems are of great importance for a successful European solar and wind energy integration. The paper also proves that not only the energy capacity but also the power capacity of storage systems is a key factor for the effective integration of variable renewable energy sources.technologies will be key drivers in paving the way towards sustainability and energy conservation. However, today the integration of VRE sources poses a challenge to be addressed for the successful decentralization of the electricity network. From the point of view of power quality, PV and wind energy have some disadvantages. The intermittent nature of VRE sources and distributed generation remain a challenge to grid operators when scheduling power generation. On the other hand, distributed energy generation may enhance the further spread of smart grids and micro grids and, therefore, ensure a greater share of clean energy in the energy mix [8][9][10][11][12][13][14].PV and wind technologies play a key role in the shift towards green growth, a low-carbon economy, and a greater share of renewables in the energy mix [15]. In the last decade, support schemes such as the feed-in-tariff system, the declining initial capital expenditure due to the boost in innovation, and technology have proved to be essential factors that underpin this phenomenon [16][17][18]. Statistics show a considerable growth of PV and wind energy globally; 7.5% of the total 26.5% share of renewables in electricity generation was produced by VRE installations in 2017. In the same year, the global built-in PV and wind capacity amounted to 941 GW (Figure 1). The key players of the PV electricity market were China (131.1 GW), followed by the EU (108 GW), the USA ...

Solar energy has an increasing role in the global energy mix. The need for flexible storage photovoltaic systems and energy storage in electricity networks is becoming increasingly important as more generating capacity uses solar and wind energy. This paper is a study on the economic questions related to flexible storage photovoltaic systems of household size in 2018. The aim is to clarify whether it is possible in the European Union to achieve a payback of the costs of flexible storage photovoltaic system investments for residential customers considering the technology-specific storage aspects prevalent in 2018. We studied seven different flexible storage photovoltaic investments with different battery technologies in Germany, France, Italy, and Spain because, in Europe, these countries have a prominent role with regard to the spread of photovoltaic technology. These investment alternatives are studied with the help of economic indicators for the different cases of the selected countries. At the end of our paper we come to the conclusion that an investment of a flexible storage photovoltaic (PV) system with Olivine-type-LiFePO 4 , Lithium-Ion, Vented lead-acid battery (OPzS), Sealed lead-acid battery (OPzV), and Aqueous Hybrid Ion (AHI) batteries can have a positive net present value due to the high electricity prices in Germany and in Spain. The most cost-effective technology was the Olivine-type-LiFePO 4 and the Lithium-Ion at the time of the study. We suggest the provision of governmental support and uniform European modifications to the regulatory framework, especially concerning grid fees and tariffs, which would be necessary in the beginning to help to introduce these flexible storage PV systems to the market.

The energy demand of mankind is constantly growing, thus the utilization of various renewable energy sources, which also reduces negative environmental effects, is becoming more and more important. Because of the achievement of climate protection targets, photovoltaic (PV) energy has an increasing role in the global energy mix. This paper presents the technical and economic aspects of different photovoltaic system configurations designed to suit the Hungarian renewable energy regulations. In this study, five alternative PV configurations were examined for systems with a capacity from 50 kW to 500 kW, related to low- and medium-voltage installations. This article also introduces and explains the Hungarian economic PV and Feed-in-Tariff (FiT) regulations, where three different investment alternatives are analyzed with the help of economic indicators. This study could help stakeholders in the market (e.g., the Hungarian industry sector and local governments) understand the possible directions of technical and economic PV development. According to the results, the payback periods in all the studied economic-technical cases were below 10 years. The experimental results show that each investment option may be a good decision from an economic and technical point of view under the Hungarian regulations in force in 2019.

This article examines the positioning features of polycrystalline, monocrystalline, and amorphous silicon modules relative to the focus points of concentrator photovoltaic modules under real meteorological conditions using a dual tracking system. The performance of the photovoltaic modules mounted on a dual-axis tracking system was regarded as a function of module orientation where the modules were moved step by step up to a point where their inclination differed by 30° compared to the ideal focus point position of the reference concentrator photovoltaic module. The inclination difference relative to the ideal focus point position was determined by the perfect perpendicularity to the rays of the sun. Technology-specific results show the accuracy of a sun tracking photovoltaic system that is required to keep the loss in power yield below a defined level. The loss in power yield, determined as a function of the measurement results, also showed that the performance insensitivity thresholds of the monocrystalline, polycrystalline, and amorphous silicon modules depended on the direction of the alignment changes. The performance deviations showed clear azimuth dependence. Changing the tilt of the modules towards north and south showed little changes in results, but inclination changes towards northwest, southwest, southeast, and northeast produced results diverging more markedly from each other. These results may make the planning of solar tracking sensor investments easier and help with the estimate calculations of the total investment and operational costs and their return concerning monocrystalline, polycrystalline, and amorphous silicon photovoltaic systems. The results also provide guidance for the tracking error values of the solar tracking sensor.

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