Deutsche Version  ACT
Electrical Storage
Electrochemical Storage 31.12.2015

The figure shows the problems in the electrical network without the use of storage.
© Tanja Kneiske/Fraunhofer IWES, 2013

The potential of electrochemical storages

Scientist explore how electrochemical energy storages can make future electricity networks stable and secure. For this purpose, they analyze the technical and economic aspects of the use of these systems. In addition, they also consider alternative techniques – such as material storage, pumping and compressed air storage - and the possibilities of load management and network expansion.

Project status Project completet
Project duration November 2012 until December 2015

The aim of the project is to develop a roadmap for use and necessary further developments of electrochemical storage systems to enable them to help stabilizing the future energy system. In order to do that, the capability of different electrochemical storage systems related to their contribution to the economic efficiency, stability and security of the future German energy system is analyzed. Furthermore alternative storage technologies, such as pumped-hydro- or compressed-air-storage systems as well as chemical energy storage and system approaches, such as demand-side-management and extension of the grid are looked at, in order to identify fields of application for electrochemical storage systems.

  • The figure shows the problems in the electrical network without the use of storage. © Tanja Kneiske/Fraunhofer IWES, 2013
  • The figure shows a corresponding improvement in the situation with the use of distributed storages. © Tanja Kneiske/Fraunhofer IWES, 2013

Within the joint research project ESPEN various aspects of the integration of electrochemical energy storage systems into the future electrical system are considered.

On the one hand technical questions, such as the expected load profiles for the investigated voltage levels, medium- and low-voltage grids, and their influence on the technical lifetime of the different storage technologies and the control- and communication concepts are analyzed. The possible technical alternatives are investigated as well as there might be cases in which other storage technologies, the extension of the grid or other concepts might be more suitable to solve the problem.

Furthermore non-technical aspects are analyzed. In addition to the economic impacts of the use of different storage technologies, the legal framework is investigated as well, in order to analyze and evaluate the technical and legal regulations, which might constrain or favour the integration of electrochemical storage systems into the energy market.

Investigations to autumn 2015

In the begining the project focuses on sub-projects 1 and 2, dealing with the definition of the grids of interest. After the completion of the first year reference grids will be available. Using these grids, the requirements for different storage technologies will be analysed.
During the third year, the project will focus on the legal framework for the use of electrochemical storage systems. Furthermore a roadmap for further developments and use of storagesystems will be established.

The joint research project is planed for three years (november 2012 until october 2015) and is coordinated by Energie-Forschungszentrum Niedersachsen (EFZN), which is located in Goslar.
The following institutes take part in the procject: Energieforschungszentrum Niedersachsen (EFZN) - Institut für Elektrische Energietechnik (TU Clausthal), Fraunhofer-Institut für Windenergie und Energiesystemtechnik (IWES), Fraunhofer-Institut für Solare Energiesysteme (ISE), Technische Universität München (TUM) - Lehrstuhl für Elektrische Energiespeichertechnik (EES), Otto-von-Guericke-Universität Magdeburg (OvGU) - Lehrstuhl Elektrische Netze und Alternative Elektroenergiequellen (LENA), Rheinisch-Westfälische Technische Hochschule Aachen (RWTH Aachen) - Institut für Stromrichtertechnik und Elektrische Antriebe (ISEA) - Lehrstuhl für Elektrochemische Energiewandlung und Speichersystemtechnik, Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW) - Fachgebiet Elektrochemische Akkumulatoren (ECA).
All of the participants are members of Interessengemeischaft für Batterien in elektrischen Netzen (IBN e.V.).


Sub-project 1: Design of reference grids

The aim of this work package is to construct reference grids for the investigated voltage levels (medium- and low-voltage) for difference scenarios for the use of electrochemical storage systems in the electrical grid. In addition to systems with mainly centralized generation, grids with mostly decentralized power production are investigated. Furthermore quantitative goals for the use of electrochemical storage systems within four pre-defined areas - energy storage in order to prevent extraordinary voltage drops or increase, storage to bridge a possible lack of renewable generation, power storage in order to stabilize the grid frequency and energy storage to prevent overloads  - are developed.

Sub-project 2: Necessary storage capacity within different voltage levels and technical and economic requirements for storage systems

Using the results of sub-project 1, more detailed scenarios for the use of storage systems within the four pre-defined scenarios are defined and evaluated qualitatively and quantitatively in order to get the optimal solution with regard to technical and economic requirements.

Sub-project 3: Alternative and additional solutions

Within this sub-project possible alternatives for the use of storage systems, such as grid extension, concepts of demand-side-management as well as the use of peak-load power plants or additional loads are investigated. The costs and impacts on grid quality, economics and reliability of these alternative solutions are analyzed. Furthermore, social and economic aspects are investigated in order to identify fields of application for which electrochemical storage systems are the optimal solution.

Sub-project 4: Characterizing, selecting and testing of electrochemical storage systems

This sub-project investigates the little known impacts of dynamic loads with high current and relatively small variation of the state of charge on storage systems. The load-profiles are the results of sub-project 2.

Sub-project 5: Use of storage systems already integrated into the electricity system

In this sub-project the use of already existing storage systems which are originally not intended to be used in the energy market is investigated. These are storage systems in UPS-units in telecommunication applications and data centers. Mainly the impacts of the use of these storage systems on their original application and their lifetime is investigated.

Sub-project 6: Life cycle costs of energy storage systems

The calculation of life cycle costs of energy storage systems has to be based on technology parameters and load profiles. The necessary technical parameters are the results of the sub-projects 2, 4 and 5, while the dynamic load profiles are the result of sub-project 2. The aim of this sub-project is to combine the parameter sets and develop a tool for calculating the energy costs for the optimally dimensioned storage systems for each technology.

Sub-project 7: Control of energy storage systems, activation and monitoring

This sub-project investigates the following aspects within the pre-defined scenarios for the use of electrochemical storage systems. At first the possibilities and constraints of stabilizing the grid using storage systems and (additional) loads, operated using only frequency and voltage are analyzed. Furthermore, at any time the capacity  for loading or unloading the storage has to be sufficient to stabilize the grid. Finally different control strategies are analyzed regarding the goals defined in sub-project 1.

Sub-project 8: Communication systems for monitoring and controlling the storage systems

Decentralized storage systems have to work properly without destabilize the grid or reducing their stabilising effect even if the communication system breaks down. Communication systems are necessary and helpful for optimizing the system as a whole. This sub-project analyzes the additional value of communication systems and evaluates their benefits to the system with regard to the additional costs. Furthermore this sub-projects analyzes the feasibility of the necessary communication systems for the control strategies defined in sub-project 7 and investigates, if these systems might be used for other aspects as well.

Sub-project 9: Legal framework for the use of , decentralized storage units

Within this sub-project possible adaptions of legal and technical regulations are investigated in order to adapt them to electrochemical storage units. Furthermore, the need for changes of existing regulations are analyzed, in order to propose recommendations for them.

Sub-project 10: Problems with accepting storage units and decentralized demand-side-management

This sub-project investigates the technical means and financial rewards to improve the acceptance of decentralized storage systems with remote-control. The goal is to develop the potential of decentralized storage units in private houses and industrial buildings and to develop means to best utilize their potential.

Sub-project 11: Dissemination of the results and establishment of a consensus within the industry

The communication of the results is important, therefore open workshops regarding various aspects of the integration of storage systems are organized during the project. Furthermore, a industry steering committee will be established, to allow industry and other stakeholders to get involved with the project and put forward their suggestions and concerns.