School of Chemical and Environmental Engineering, University of Nottingham

The Supercapattery has a storage capacity and charging/discharging capacity that lies between those of super capacitors and conventional accumulators.

The aim of the project is to design a new integrated system for storing en-ergy consisting of Supercapattery and power electronics interface. The core materials are chemically modified carbon nanotubes, which are particularly suited to load levelling in electricity networks. The power electronics inter-faces ensure that the current flow is integrated in a stable and high-quality manner. The demonstration of a prototype enables this new system to be re-liably evaluated. The rating relates to the requirements of an operation in an energy storage bank with a high power and energy level and electricity net-work characteristics such as peak load levelling and the independent power control system.

Center for Applied Energy Research, University of Kentucky

Off-peak energy storage enables demand to be covered at peak times. Electrochemical dual-layer capacitors (EDLCs) offer many benefits: a high power density, low maintenance and long life span.

For over three years an electrochemical cell for the high voltage sector has been developed and researched, which is suitable for storing energy in supply networks with excellent power and energy density. The plan is to study the synthesis, characterisation and evaluation of porous carbons with high energy density for asymmetric EDLCs. Graphite carbons are also being assessed as electrode materials for a new type of electrochemical cell based on lithium-ion. They could achieve an energy density that is three times as high as the current generation of electrochemical capacitors in use.

E.ON Energy Research Center, RWTH Aachen

Institute for Power Electronics and Electrical Drives, RWTH Aachen

Institute for High Voltage Technology, RWTH Aachen

Institute of Energy Technology, Aalborg University

Storing energy reliably is essential for the supply networks with an increasing proportion of volatile generators such as wind energy plants and in weak segments of the network.

The aim of this project is to design and develop a modular battery storage system (BESS) taking into account the interaction between the storage sys-tem and the power electronics. BESS systems allow an extremely short reac-tion time and large amounts of energy, therefore representing another tech-nical method of regulating the network in future. Due to their high energy density and modularity, these systems are easy to integrate with existing networks. High-voltage batteries for direct connection with a direct current (DC) intermediate circuit on an electronic power converter or combined with a DC/DC transformer between two different voltage levels are looked at and analysed in detail. At the end of the project, specifications will be available for an optimal storage system according to ecological and economic criteria.

University of Strathclyde, Electronic and Electrical Engineering

With a widespread use of electric vehicle batteries, these can be used as local energy storage devices, which can absorb electricity from the network and release electricity into the network depending on the network conditions and charging state of the battery packs.

The aim of this project is to assess the system benefits of energy storage with dual use. It is necessary to take a typical vehicle's cycle of operation into account. Different application areas of storage are being studied: frequency reserve, instant reserve, load levelling (levelling between off-peak and peak times) and the load reduction on subassemblies under high loads (distribution systems). Also looked at are load reduction in the transmission network, value creation for local power generation (e.g. from renewable energy sources that cannot be planned) and ways to complement large-scale energy production with renewable forms of energy.

Institute of Power Systems and Power Economics, Technische Universität Dortmund (Dortmund Technical University)

Energy storage systems significantly contribute to efficient management in distribution networks.

The project follows an innovative strategy for integrating distributed storage capacities. Linking electric vehicles creates an intelligent system of autono-mous energy storage systems. For this purpose, a non-centrally organised management system is being developed for electric vehicles and other dis-tributed energy storage systems. A multi-agent system assumes the role of automatically administrating and coordinating energy storage systems based on the DEZENT project. Furthermore, load flow calculations are performed in real time. Besides preserving conventional resources, the aim is to maximise profits for all those involved. By optimising the supply configuration, expen-diture for energy imports is reduced and the capacity utilisation of the net-works is increased.

French National Institute of Solar Energy (INES), French Atomic Energy Commission (CEA)

Institute for Power Electronics and Electrical Drives, RWTH Aachen

The so-called BEST project examines the use of different commercially available electrochemical storage systems in mobile and static applications.

The technical data of how the storage systems work is first collected systematically. This involves an active exchange between the electricity generators and vehicle manufacturers. Accumulators with large energy storage capacity and powerful super condensers are then tested for their energy properties and life span. The combination of the two promises benefits for the storage system. Modelling how the storage system operates by applying an imped-ance-based substitute circuit diagram is planned in the third phase. Designing storage system models makes future system integration considerably easier. The results are used for technical/economic analysis and to illustrate the best storage system for every field of application.

University of Nottingham, School of Mechanical, Materials and Manufacturing Engineering

Central to this concept is the view that storing energy in the form of compressed air in large flexible containers ('energy bags') at considerable depths on the sea bed is technically feasible, economically attractive and environmentally friendly.

This project makes the first step towards an integrated offshore system con-sisting of compressed air storage devices and renewable energy production. As a result it has been possible to considerably reduce the negative effects on the power system on land, which are due to unforeseen fluctuations. The re-search activity includes the following work packages: Designing and develop-ing the flexible underwater container, developing heat exchangers for the best possible utilisation of the heat generated during compression and the use of floating heat storage devices and additional equipment ('thermal top-up'). This is followed by the expander configuration and system simulations as well as an evaluation of cost-effectiveness.

Institute for Heat and Fuel Technology, Technische Universität Braunschweig (Brunswick Technical University)

Energy storage systems are essential for the operation of supply networks. Their importance is increasing due to the use of renewable forms of energy.

This project studies new ways of improving compressed air storage systems, which are supplied with wind energy at times of oversupply and supply elec-tricity to the system during times of demand. The planned compressed air storage power station is operated on an isobaric or almost isobaric basis. To further increase the level of efficiency, researchers use a heat storage system and a combined cycle gas and steam turbine unit.

The compressed air storage power station studied here has the option of be-ing operated conventionally and also works when there is a lack of wind power and the storage systems are empty. This reduces downtime and the investment portion of costs in the energy prices. Fundamental thermodynamic questions about the best design of the plant and the heat storage system are studied in the project just as much as how to best integrate the storage power station in a network made up of existing storage systems.

Institute for Energy Economy and Application Technology, Technical University Munich

In the case of combined heat and power (CHP) systems, the processes of taking energy from and feeding energy into the grid can only be controlled to a limited extent. Innovative heat storage management can break the link between heat production and demand at CHP plants.

The controlled operation of CHP modules enables a steady gas demand and power generation adapted to the network load, which is not possible with the previous systems and impairs their cost-effectiveness. Multifunctional heating systems consist of a CHP module, heat storage system and a peak load boiler. Theoretical load profiles are first designed for the plants based on typical days and tested in practice using non-linear influencing factors. The control system can impress feedback controls on the CHP module, thus safeguarding the developed storage management system. The results represent future load profiles of electricity and natural gas. Finally the profiles developed are evaluated. A defined supply area is used to show up feedback effects from multifunctional heating systems on the supply network.

Chair of Thermodynamics, Ruhr University Bochum (Ruhr-Universität Bochum)

Like electricity storage, carbon capture and storage (CCS) is seen as a key technology for reducing greenhouse gases. Both technologies require exact fluid property models.

At high pressure, state variables of gas mixtures and complicated phase equi-libriums have to be accurately calculated. Researchers focus on developing a data model for chemical media, which is sufficiently accurate for all relevant mixtures, temperatures and pressure ratios. As a starting point, the GERG 2004 equation of state is used as an internationally agreed standard for the chemical substance properties of natural gases. The applicability is analysed for mixtures and states that are typical for compressed air storage power sta-tions and CCS processes. The application of the fluid property model is tested in typical simulation programs and the influence on process calculations studied.