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The support of prosumers in the countries of the European Union has registered significant growth, especially regarding the energy produced from photovoltaic panels in households or in commercial spaces after 2020. Romania will promote the distributed generation from renewable sources with installed power between 3 kW and 100 kW, the on-grid installations being subsidized through the financial support of the Environmental Fund Administration (3 kW for residential prosumers) with,,photovoltaic green house,, program and Ministry of Economy, Energy and Business Environment with the,,Electric Up,, program (between 27 kW - 100 kW power with recharging stations of at least 22 kWp for electric and hybrid electric vehicles for commercial prosumers). This paper proposes an analysis of a commercial prosumer with a specific case study in north Dobrogea in Romania, comprise of a comparative analysis for an integrated 30 kW comercial user with 44 kW charghing station for electric and hybrid electric vehicles installed on the ground, in order to reduce the energy consumption with a management system for the optimal coordination of the energy to the owner's need, also to see the rentability of the system when it's a comercial user and the own consumption is higher during the day. The project applies to Romanian legislation and can be used for similar projects considering that in coming years these types of systems will appear. [ABSTRACT FROM AUTHOR]

Frequency control in autonomous microgrids (MG) with high penetration of renewable energy sources represents a great concern to ensure the system stability. In this regard, this paper presents an enhanced control method for battery energy storage systems (BESS) to support the frequency of MG and with the ability of disconnecting from the MG to supplying in the island mode a local consumer. A frequency controller, combining a conventional droop control with an inertia emulation function, governs the BESS active power transfer during the primary frequency control level. The BESS may also provide voltage support in the point of common coupling with the MG. Moreover, the proposed BESS may compensate, partially or totally, the power absorbed by the local loads in order to improve the MG frequency response. When the MG power quality worsens below a certain level, in terms of voltage and frequency, the BESS detaches from the MG and continues to operate islanded. The reconnection is accomplished following a smoothly resynchronization of the local voltage with the MG, without disturbing the local loads supply. Additionally, this paper also discusses about the aspects related to the BESS management and its integration within the proposed system. The simulation and experimental results assess the feasibility of the proposed control solutions. [ABSTRACT FROM AUTHOR]

This study analyses the integration impact of battery energy storage systems (BESSs) on the short‐term frequency control in autonomous microgrids (MGs). Short‐term frequency stability relates with the primary or speed control level, as defined in the regulations of the classical grids. The focus is on autonomous MGs that dynamically behave similarly to the classical power systems. This is the systems case with classical distributed generators (DGs), but which can also contain renewable energy sources (RESs) in a certain penetration level. During MG islanded operation, the local generators take over most of the frequency control process, by means of their automatic generation control, which include inertia response and primary control. However, RES‐based DGs are rarely able to provide grid frequency support, as they lack controllability and usually the power conversion chain does not have the possibility of storing and releasing energy when required by the system. Therefore the need of boosting the MG power reserves by adding energy storage systems is often a requirement. The study highlights the improvement in the MG short‐term frequency stability brought by an original BESS control structure enhanced with both inertial response and an adaptive droop characteristic during battery state‐of‐charge limitations. The conducted analysis is accomplished by adopting aggregated models for the involved control mechanisms. The developed model is analysed in frequency domain, whereas an experimental test bench including a real‐time digital simulator with BESS controller in a hardware‐in‐the‐loop structure is used for assessing the system performances. [ABSTRACT FROM AUTHOR]