Symbiose-4-I&C - Optimal decentralized hybrid storage technologies among different energy systems -4-Industry and Commerce

The project Symbiose-4-I&C analysed the coupling of existing energy networks/-carriers, established on centralized energy network nodes or directly next to a consumer (households, industry and commerce) and the benefits of applying decentralized storage technologies. The optimal position, dimension and the right storage and conversion technology and an optimal energy wide operation of larger consumer groups were estimated for an urban model region.

Short Description

Starting point/Motivation

The intensified integration of renewable energy producers is essential for achieving climate goals, like the "2020 targets" in Austria. Wind power, photovoltaics (PV) and biomass are the predominant propagating renewable generation technologies. However, existing electricity grids were often not designed for the distributed and volatile feed-in of wind power and PV and therefore can face difficulties with such infeeders. The utilization of decentralized storage and the flexibility of conversion technologies for decentralized distributed coupling of existing energy supply infrastructures (electric-, gas-, and domestic heating grid) is one possible solution.

The research project "Symbiose" investigated the role of distributed storage- and conversion technologies for energy distribution networks of renewable model regions (a rural and an urban area). The project showed that with a proper storage capacity and storage operation, a high share of renewable producers in the existing electrical distribution grid could be reached. The consumer itself turned out to be the most suitable location for coupling the existing energy infrastructures. This allowed a significant reduction of total energy supply from the upper grid levels. The examinations of "Symbiose" project were based only on the behavior of domestic consumers and agricultures. In both model regions industrial and commercial customers were not taken into account.

In the research project "Symbiose 4-IuG", new potentials, especially the role of industrial and commercial customers in terms of coupling of energy networks and the storage of renewable energy were pointed out. Involving the stakeholder "Industrial and Commercial Customer", new statements were made regarding energy supply, use of storage and conversion technologies and CO2 emissions.

Contents and Objectives

The projects objective was to determine the optimal allocation and placement of decentralized storage and conversion technologies and the coupling of existing energy networks/-carriers in urban areas on a consumer level. A major focus was the examination of commercial and industrial customers in the hybrid network and their flexibility potentials.

The aims of the project were as follows:

  • to show that a higher overall energy efficiency and an optimal usage of renewable energy sources can be achieved in the urban region by coupling of different energy sources (electricity-, gas- and heating system) on centralized energy network nodes or directly next to a consumer. The consumer itself should benefit from this achievement as well.
  • to determine the remaining demand of decentralized storage technologies considering the installation of conversion technologies for coupling the existing infrastructures and the shifting potentials of commercial and industrial customers.
  • to highlight the potential and benefit of coupled infrastructures for the industrial and commercial sector.
  • to show the effects of coupling the energy networks on the networks operation.
  • to determine potentials of reducing the energy import dependency and CO2 emissions for urban areas in the future when implementing the ideas of "Symbiose-4-IuG" project.


To accomplish these goals, the energy system of the project partner MPREIS was investigated closely. Their loads and energy system were represented as dynamic models in an appropriate modelling software (Dymola).

The energy system of the urban model region was adapted for the connection of several commercial and industrial customers. The regenerative potential determined in the preliminary "Symbiose" project was redistributed in the urban model region. Customers and decentralized generation were then included and the energy system of the model region was optimized.
The goal of optimization was to comply with technical limitations of the electrical grid, taking into account decentralized storage and conversion technologies and a conscious use of determined flexibility potentials of industrial and commercial enterprises even with a massive expansion of renewable energy sources. This was done considering minimal total costs of the energy system. The optimization was conducted considering the different perspectives of key stakeholders.


Benefits of different stakeholders in the city:

A combined consideration of electricity and heat infrastructure in a city makes sense. The coupling of existing energy infrastructures on the industrial and end-user side makes it possible to significantly reduce the overall energy consumption from higher network levels.

The stakeholder industrial / commercial customer:

Industrial and commercial customers play an important role in coupled energy networks to increase sustainability. The results with consideration of industrial and commercial customers confirm and reinforce the statements of the predecessor project especially regarding the improvement of the sustainability and the reduction of energy import in distributed energy grids.

Coupling of energy networks:

Decentralized electrical storage and conversion technologies favor a more even utilization of existing energy networks with a high share of decentralized generation.

High BEV penetration, even with controlled charging and relatively low energy increase, leads to a significant increase in power of the low-voltage grid and requires grid-friendly measures.

Transfer of the question to other cities:

A purely decentralized accounting of an urban energy system based on performance is not economically and technically reasonable.

Prospects / Suggestions for future research

Consideration of other market factors

In addition to the extensive factors and parameters that were already taken into account in the "Sybmiose-4-IuG" optimization model, other market-related factors could be included in the model, such as dynamic energy prices for electricity and heat, as well as additional revenues through flexibility measures for the control energy market.

Consideration of dynamic system boundaries

In the present project, the model region city was optimized as an autonomous region with static system boundaries. The energy flow from and to the higher grid levels was only limited by the existing technical system limits (e.g. electrical system, the nominal capacity of the transformer,...) without consideration of an actually possible power flow in the transmission network levels. One possibility would be to further develop the optimization model and to include a dynamic system boundary. The dynamic system boundary could be determined as part of a pre-simulation or pre-optimization of the transmission network level and transfered to the optimization model.

Development of an open source tool of the developed optimization model

The developed optimization model could be extended to an open source software tool. This would allow the application of the project idea of the developed model to different cities in Austria. Statements of the results and the benefits of the individual stakeholders could be compared.with the present project.

Demo implementation

The next logical step would be an implementation of the hybrid network idea in a real urban area with electricity, heat / cold and gas network. The energy flow across grids and energy carriers could be tested in real time using the implemented optimization model considering the flexibility of field operation.

Project Partners

Project management

TU Wien, Institut für Energiesysteme und Elektrische Antriebe

Project or cooperation partners

  • TU Wien, Institut für Energietechnik und Thermodynamik
  • MPREIS Warenvertriebs GmbH
  • Vorarlberger Energienetze GmbH

Contact Address

Technische Universität Wien
Institut für Energiesysteme und Elektrische Antriebe
Arbeitsgruppe Elektrische Anlagen
Univ.-Prof. Dr.-Ing. Wolfgang Gawlik
Gußhausstraße 25 / E370-1
A-1040 Wien
Tel.: +43 (1) 58801-370111
Fax: +43 (1) 58801-370199