A Case Study on Distributed Energy Resources and Energy-Storage Systems in a Virtual Power Plant Concept: Technical Aspects

Tomasz Sikorski,Marian Sobierajski,Przemysław Janik,Beata Solak,Magdalena Węglarz,Edyta Ropuszyńska-Surma,Daniel Bejmert,Dominika Kaczorowska,Zbigniew Leonowicz,Jarosław Szymańda,Paweł Kostyla,Jacek Rezmer,Wilhelm Rojewski,Michal Jasiński,Robert Lis

doi:10.3390/en13123086

Abstract

The article presents calculations and power flow of a real virtual power plant (VPP), containing a fragment of low and medium voltage distribution network. The VPP contains a hydropower plant (HPP), a photovoltaic system (PV) and energy storage system (ESS). The purpose of this article is to summarize the requirements for connection of generating units to the grid. Paper discusses the impact of the requirements on the maximum installed capacity of distributed energy resource (DER) systems and on the parameters of the energy storage unit. Firstly, a comprehensive review of VPP definitions, aims, as well as the characteristics of the investigated case study of the VPP project is presented. Then, requirements related to the regulation, protection and integration of DER and ESS with power systems are discussed. Finally, investigations related to influence of DER and ESS on power network condition are presented. One of the outcomes of the paper is the method of identifying the maximum power capacity of DER and ESS in accordance with technical network requirements. The applied method uses analytic calculations, as well as simulations using Matlab environment, combined with real measurement data. The obtained results allow the influence of the operating conditions of particular DER and ESS on power flow and voltage condition to be identified, the maximum power capacity of ESS intended for the planed VPP to be determined, as well as the influence of power control strategies implemented in a PV power plant on resources available for the planning and control of a VPP to be specified. Technical limitations of the DER and ESS are used as input conditions for the economic simulations presented in the accompanying paper, which is focused on investigations of economic efficiency.

Highlights

A Virtual Power Plant (VPP) is still an actual approach and there is not a standardized definition for the framework of a virtual power plant (VPP) in the literature
The results show that the number of distributed energy resources and the available storage capacity of battery energy storage has an impact on the economic efficiency of the VPP
This paper provides the real case example of calculation and simulation focused on the determination of maximum power capacity of the energy storage system (ESS) planned In terms of VPP efficiency and sensitivity, it is important to identify the maximum level of ESS power capacity that can be connected in the planned node to be installed in the selected network node

Summary

Introduction

A Virtual Power Plant (VPP) is still an actual approach and there is not a standardized definition for the framework of a VPP in the literature. The origin of the terminology of “Virtual Power Plant” may be traced back to 1997, when S. In the book “The Virtual Utility—Accounting, Technology and Competitive Aspects of the Emerging Industry” defined Virtual Utility as flexible cooperation of independent, market-driven actors that assures an efficient energy service expected by the consumers without the need for appreciating assets [1]. A VPP manages distributed energy resources (DER). Named distributed generation (DG) units [2]. Wind, solar and hydroelectric power generation units are interconnected. Managing them together enables them to be more effective [3,4,5]

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Discussion

Conclusion