New network structures

The ENSURE Kopernikus project

How can the electricity grid be adapted to an irregular supply?

Until now, electricity has mainly been produced in centralised power stations that are able to respond to fluctuating demand from consumers. The structure of the network is also as of today configured around this type of electricity generation.

Renewable energy generation is however predominantly decentralised, mainly in solar and wind installations. This means there are far more, smaller, producers feeding their electricity into the grid. Under certain operating situations this can give rise to problems where the direction of flow is reversed in individual parts of the network. The position can also arise that when high volumes of electricity are being fed into the system, the network’s available transport capacity may be exceeded. In addition, it is difficult matching energy production from renewable sources - which is weather-dependent and so itself fluctuates - to demand that also varies. We consequently have to plan for both excesses and shortages of supply.

To counteract these problems and continue to guarantee high security of supply, a network is needed that can respond flexibly, even where a large part of energy production is subject to fluctuation and demand also constantly changes.

It is generally accepted that increasing electricity generation from renewable sources dictates expansion of the network, and planning and implementation for this is underway in some areas.

“How big does the network in Germany need to be and how are we to build the optimal network structure? No-one yet knows what form of network structure we will have when 80 to 90 percent of our electricity is produced from renewable sources. Finding the answers is the goal of the ENSURE project.”

From a speech by Federal Minister of Education and Research Johanna Wanka on 13 October 2016 at Jülich.

Research topics

Network expansion must be looked at in conjunction with energy storage: the more storage available, the less network expansion we need, and vice versa.

Linking the electricity network to the heating network (Power-to-Heat) and the gas network (Power-to-Gas) opens up new options for storing, and flexibly transporting, large quantities of energy. This conversion process does however lead to efficiency losses, increasing overall energy demand.

Many consumers can be flexible in terms of when they take their electricity (certain industrial processes, heat pumps, cooling systems) allowing them to adapt to fluctuating production from renewable sources and to the network’s transport capacity (network-beneficial behaviour). The connection and disconnection of consumers can be market-based (time-dependent electricity pricing) or centralised (by network operators).

Renewable generation is for the most part connected to the distribution network, rather than the transmission network. Better distribution networks on the one hand simplify energy transport, but at the same time make network management more complex.

New electronic components that are either more durable (such as higher performance, bi-directional current flow) or that can better control current flow (phase shifters, UPFC = Unified Power Flow Controller) facilitate the transport of energy from generators to consumers. High-voltage DC transmission is a technology allowing efficient electricity transmission over long distances.

Geographical discrepancies between production and consumption within the integrated European network are increasing. To improve flexibility, low-loss transmission using direct current is becoming ever more important at the level of the transmission network. New technologies allow efficient and low-cost energy transport within Europe.

The aim of this topic is the construction of the electricity network in such a way as to allow individual regions to independently supply their own energy needs. Enabling this will require very high storage capacities, although management will become simpler and such regions will become immune to power cuts and network disruptions in other regions.

The ENSURE consortium

The “New network structures” Kopernikus project: ENSURE (New Energy Network StructURes for the Energiewende)

The objectives set for the Energiewende up to 2050 are achievable only if the number and performance of installed renewable energy facilities increase significantly. Far-reaching changes to the electricity supply system are needed if we are to continue to guarantee security of supply. These include both the further expansion of a central energy distribution system and the creation of decentralised structures at regional level. All the measures aimed at optimising energy supply are both accompanied and driven by the progressive digitalisation of the energy industry and the growing inter-linking of the various sectors (electricity, gas, heat, transport).

What is the objective of the Kopernikus project?

The research work will contribute to the successful economic shaping of the Energiewende. The concrete proposals emerging from the project for future structures and management strategies will lead to improvements in the performance and efficiency of the system as a whole, with the aim of reducing costs for both the operator and the end-customer.

To adapt the electricity supply to the changes accompanying the Energiewende, a rational structure comprising both centralised and decentralised supply needs to be identified. The project divides into three key topics: researching new system structures, stable system management mechanisms and the integration of new technologies into the supply system. A further topic comprises the subsequent implementation and testing of the overall energy supply system in the form of an industrial-scale network demonstrator. All the activities are to be accompanied by a comprehensive analysis of the socio-economic factors. This element involves all stakeholders including prosumers (producer-consumers) and runs alongside the key topics above.

What makes the consortium so attractive?

ENSURE is an interdisciplinary consortium comprising established partners from the worlds of science, business and civil society. Six core partners have taken on the leadership of the project, being among the best-known actors in the relevant areas of research and application. The broad spectrum the research addresses is reflected in the presence of a further 17 prominent partners in the selected consortium, including from civil society. The 23 consortium partners are organised in a flexible structure which explicitly provides for the integration of further partners. The selection of a spokesman for the project, determined during the course of the project depending on the research topics, fits with this form of organisation. Prof. Dr.-Ing. Holger Hanselka, the President of the Karlsruhe Institute of Technology, is acting as the spokesman for the overall consortium during the first project phase.

Contribution to the energy system

The ENSURE project contributes substantially to optimisation of the future energy system, in that the results of the research may prevent misplaced investment and allow existing infrastructures to be expanded in a targeted fashion. The current network development plan (NEP 2025) provides for up to €34,000 million for the investment costs alone for the required expansion of the network up to 2025, clearly showing the enormous economic leverage of this project. At the same time, increased system efficiency offers ecological advantages through reduction in the primary energy required.

Contact person:

Karlsruhe Institute of Technology, Prof. Dr.-Ing. Holger Hanselka