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 ...

Despite the apparent stability of the electricity system from a consumer’s point of view, there is indeed significant effort exerted by network operators to guarantee the constancy of the electricity supply in order to meet demands any time. In the energy sector models provide an important conceptual framework to generate a range of insight, examine the impacts of different scenarios and analyze the supply and demand of energy. This paper presents a user-oriented and transparent modeling concept of the European calculator, a tool for delineating emission and sustainable transformation pathways at European and member state levels. The model consists of several modules of different sectors, where the energy supply module includes sub-modules for electricity generation, hydrogen production and oil refinery. The energy storage requirement module investigates how new technologies can help the stability of the European electricity system with increasing renewables penetration, demand-side measures and decarbonization paths. The objective of this study is to introduce the concept of this module with the main logical steps, especially the input parameters, assumptions, the basic data of electricity trade and maximum energy storage potential levels. The article also introduces and explains the feasibility of the theoretical maximum gross electricity generation potential from variable renewable energy for the European Union including Switzerland, compared to the demand in 2040. According to the results the electricity systems in the future will need to show ever increasing flexibility in order to cope with variable renewable energy production on the supply side, and shifting patterns of electricity consumption on the demand side.

The aim of the study is to compare the tilt angle-orientation and dual-axis tracking characteristics of mono-(m-Si), polycrystalline (p-Si), and amorphous silicon (a-Si) modules in the summer of 2017, under real meteorological conditions with simulated data. The most important new element of our study is that, besides a comparison of the three most significant photovoltaic types, the technologies are differentiated by examining specific energy generation using dual-axis tracking and four different orientations at 5-degree intervals compared to simulated values, near to the summer solstice. For these types of measurements, as far as we are aware, there is no previous reliable, well-supported, comparative data. The simulated data show less accurate results, proving the importance of real data. Based on simulated data, the tilt angle and orientation showed about 10% favorable values compared to reality. Knowing our results can make it easier to plan investment, and estimate the investment and operational costs and their return on crystalline and amorphous silicon solar modules, for both sun-tracking and fixed systems with various orientations and tilt angles.