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Annegret-Cl. Agricola: results on the dena Distribution Grid Study.

Home Press releases Electricity distribution grids require significant expansion for the energy turnaround.

Electricity distribution grids require significant expansion for the energy turnaround.

dena’s Distribution Grid Study calculates the scope of and investment requirements for grid expansion by 2030 at low, medium and high voltage levels.

By 2030, the electricity distribution grids in Germany require expansions of between 135,000 km and 193,000 km, and 21,000 to 25,000 km must be converted. This will entail investments of between € 27.5 billion and € 42.5 billion. These are the findings of a new study introduced by the Deutsche Energie-Agentur GmbH (dena) – the German Energy Agency – in Berlin today.

The expansion and investment requirements depend on the proportion of renewable electricity generation in 2030. To date, the distribution grids in Germany have been used to transport electricity to the end consumers. As part of the expansion of renewable energy and decentralised electricity generation, the electricity distribution grids already have to absorb a high proportion of electricity from solar and wind power stations. This proportion will increase in the years to come, meaning that the present capacity of the distribution grids will no longer be sufficient to transport electricity from renewable energy sources, which is not needed locally, to other regions.

“The German distribution grids require significant expansion and modernisation. We will only actually be able to distribute and consume electricity from the decentralised renewable generation systems if we expand the grid infrastructure accordingly. Infrastructure expansion must keep pace with the expansion of renewable energy sources,” emphasises Stephan Kohler, Chief Executive of dena. Kohler urges: “To guarantee the investments in grid operations and maintenance of the distribution grid, the Federal Network Agency legally mandated an attractive profit. However, our study reveals that in practice the profits from increasing integration of renewable energy systems and the resulting grid expansion are not adequate for the distribution grid operators to survive. Distribution grid operators whose grids require significant expansion cannot earn the profit mandated. The legal requirements must be adapted soon to achieve the investments required in distribution grids suitable for future needs.”

The medium and high-voltage levels are particularly in need of expansion.

The dena Distribution Grid Study calculated the extent to which German distribution grids must be expanded to use the electricity generated by renewable sources fully. Various expansion goals were assumed. In the first scenario, the expansion goals in accordance with guideline scenario B of the 2012 Grid Development Plan was assumed for transmission grids. The second scenario is based on the expansion goals of the German Federal States, which call for increased and faster expansion of wind energy and photovoltaics. Both scenarios require the construction of new electricity lines and transformers at all distribution grid levels and conversion of existing high-voltage overhead line routes.

Results of Grid Development Plan 2012 scenario B:

  • Grid expansion by 2030: 135,000 km
  • Grid conversion by 2030: 25,000 km 
  • Investments by 2030: € 27.5 billion.

Results of the Federal States scenario:

  • Grid expansion by 2030: 193,000 km 
  • Grid conversion by 2030: 21,000 km
  • Investments by 2030: € 42.5 billion.

Relative to the existing grid infrastructure, the expansion requirements are greatest at the medium and high-voltage levels: At the high-voltage level, up to 19 percent must be built from scratch and at the medium-voltage level, this figure is up to 24 percent. That is because the medium and high-voltage levels not only have to accept electricity fed in from renewable energy systems, they must also transmit electricity from renewable sources which cannot be consumed at subordinate levels. The costs are highest at the high-voltage level, as the operating technology for electricity transmission is far more cost-intensive than at lower voltage levels, and existing routes must be converted.

Framework conditions place distribution grid operators with major expansion requirements at a disadvantage.

The costs grid operators can claim are governed by laws and regulations in Germany. The Incentive Regulation Ordinance (AregV) defines the upper revenue limits and the resulting cost structure for each distribution grid operator. The dena Distribution Grid Study analysed the investment requirements for expansion and maintenance of the electricity distribution grids. The study finds that under the existing regulatory conditions, distribution grid operators whose grids require significant expansion work cannot earn sufficient profits. Conversely, that means that the incentives to finance the required grid expansion are inadequate.

Grid expansion can be reduced, but further research is required.

The dena Distribution Grid Study examined various technical options which can contribute to reducing grid expansion in future and are fundamentally technically feasible. Innovative operational resources (cables, transformers, protective devices) which optimise the use of the grid infrastructure, for example controllable local grid transformers, have the most potential as they facilitate better utilisation of the permitted voltage range. Other high potential options include adaptation of technical guidelines and down-regulation of power peaks of renewable generation. The technical options for reducing grid expansion and their economy must be examined in greater detail and should be considered when designing future energy-industry framework conditions. The contribution of renewable energy sources to the provision of system services and future cooperation between transmission and distribution grid operators require further scientific study.

Study design and project partners.

The dena Distribution Grid Study determined the need for development in all German electricity distribution grids. To do so, it analysed the real grid, generation and load structure data in Germany. That makes the new dena study the first analysis of German electricity distribution grids based on an evaluation of comprehensive and real grid data. Data from German distribution grid operators which supply more than 50 percent of Germany’s surface area was incorporated.

The study focused on the expansion and conversion needs of the electricity distribution grids for integrating decentralised electricity generation from renewable energies and combined heat and power generation. In addition, it also examined whether the current regulatory framework is suitable to guarantee the profit mandated by the legislator for electricity distribution grid operation if the expansion of renewable energy continues.

dena compiled the study together with distribution grid operators, scientific research partners and auditors. The technical report section was drawn up by Prof. Dr.-Ing. habil. Christian Rehtanz, and the regulatory part was drawn up by Prof. Dr. Gert Brunekreeft. The dena Distribution Grid Study was reviewed by auditors Prof. Dr. Helmut Lecheler, Prof. Dr.-Ing. Ulrich Wagner and Prof. Dr.-Ing. Rolf Witzmann during the project phase. In order to permit exchanges with a broad group of interest groups and experts, an advisory board featuring representatives from business, science and politics, which supervised all production phases of the study, was assembled.

Project partners: EnBW Regional AG, E.ON Bayern AG, E.ON Edis AG, E.ON Netz GmbH, ESWE Netz GmbH, EWE NETZ GmbH, LEW Verteilnetz GmbH, Mitteldeutsche Netzgesellschaft Strom mbH, N-ERGIE Netz GmbH, Netzgesellschaft mbH Chemnitz, NRM Netzdienste Rhein-Main GmbH, Rheinische NETZGesellschaft mbH, Rhein-Ruhr Verteilnetz GmbH, Städtische Werke Magdeburg GmbH & Cc KG, Thüga AG, Vattenfall Europe Distribution Berlin GmbH, WEMAG Netz GmbH.

Research partners: Prof. Dr.-Ing. Christian Rehtanz, Technical University of Dortmund/ef.Ruhr, Prof. Dr. Gert Brunekreeft, Jacobs University of Bremen

Auditors: Prof. Dr. Helmut Lecheler, Free University of Berlin, Prof. Dr.-Ing. Ulrich Wagner, German Aerospace Center, Prof. Dr.-Ing. Rolf Witzmann, Technical University of Munich

Advisory board: Bavarian Ministry of Economic Affairs, Infrastructure, Transport and Technology, Federal Network Agency for Electricity, Gas, Telecommunications, Post and Railways (BNetzA), German Association of Energy and Water Industries (BDEW e.V.), German Association of Consumer Centres and Consumer Associations - Verbraucherzentrale Bundesverband e.V. (vzbv), German Renewable Energy Federation (BEE e.V.), German Solar Industry Association (BSW e.V.), German Association of New Energy Providers (bne e.V.), Federation of German Chambers of Industry and Commerce (DIHK e.V.), Ministry of the Environment, Climate Protection and the Energy Sector of Baden-Wuerttemberg, Ministry of Economics and European Affairs of the State of Brandenburg, Lower Saxon Ministry of the Environment and Climate Protection, Association of the Electrical Engineering, Electronics and Information Technology (VDE/FNN e.V.), Association of the Industrial Energy and Power Industry (VIK e.V.) and the Association of Local Public Utilities (VKU e.V.).

Further details on the dena Distribution Grid Study:


  • dena Distribution Grid Study (in German)

    Expansion and Innovation Requirement of the Electricity Distribution Grids in Germany to 2030.

     (8.7 M, PDF)


  • Summary of results (in German)

    Electricity distribution grids in Germany must be expanded if the energy turnaround is to be a success.

     (1.2 M, PDF)


  • Short introduction (in German)

    Press conference on the dena Distribution Grid Study.

     (497 K, PDF)


  • Diagram (in German)

    The German electricity grid

     (168 K, PDF)