Network operation and system stability

The alternating current used in the electricity grid in Europe always oscillates at the same frequency of 50 hertz. If there is too little current, this power frequency drops; if there's too much electricity, it rises. If the power frequency deviates too much from the setpoint value of 50 hertz, some power plants and consumers may incur damage or power failures may occur. It is the responsibility of the transmission system operators to always ensure that the grid frequency remains stable. They therefore use what it known as balancing power to compensate for deviations in frequency.

In addition, as some sections of the grid are not sufficiently developed, bottlenecks in electricity transmission can arise. The electricity grid therefore needs to be expanded and made more flexible. Improved forecasting for weather, power generation and consumption also enables better planning to take place and facilitates grid operation. Using power storage and increasing the coupling of the electricity grid with other sectors of the energy system (heat, transport) creates even greater scope for optimising the operation of the grid. As the use of large power plants declines, system services designed to stabilise the power grid, such as the targeted feed-in of reactive power to maintain voltage levels, are becoming increasingly important. In order to enable greater volumes of renewable electricity to be fed into local grids, the rigid transmission ratios between different voltage levels in the power grid used up to now can be made more flexible. This is achieved by using adjustable local network transformers.

Within the SINTEG programme, a number of projects are focusing on ways to ensure that the electricity grid remains stable when high shares of renewables are fed in. One example is a project in the NEW 4.0 showcase, in which testing is being undertaken on how reactive power could be provided by wind turbines. A market design for dynamic reactive power feed-in is also to be developed. New strategies for the management of distribution networks are being tested in the enera showcase. By actively managing reactive power, the aim is to minimise the load on transformers. The C/sells showcase is focusing on developing improved forecasting methods in order to predict future grid conditions and energy flows at a high degree of regional detail. This is to enable impending bottlenecks in the grid to be obviated.

More than grid expansion: SINTEG is building a smart electricity grid

The aim of the SINTEG programme is to link up energy systems that work with high shares of renewables and to manage them using smart technology. The focus is on developing secure and efficient processes that are suitable for use in mass markets, innovative technologies, and market mechanisms that can be used to create flexible smart grids and markets. A core task in this is to build a digital data infrastructure that enables the integrated energy system to be managed in the best possible way. This also includes smart markets in which quantities of energy or services linked to these are traded among various market partners based on the grid capacity available at a specific time. Work is also being undertaken to restructure and automate coordination sequences for managing the electricity grid.

These activities are to lead to the development of blueprints for the smart energy system of the future, which can be applied in Germany and right around the world. This will not only help mitigate climate change, but will also open up opportunities for the German export industry. As part of the SINTEG programme, different solutions are being developed and tested in practice across a multitude of projects. The five SINTEG showcases all use data platforms that collect information about the state of the energy system, the availability of flexibility options, and forecasts for predictive system operation. In this way, these platforms form the basis for the development of digital business models. Each of the five showcases has a different focus as it develops its respective data platform. For example, C/sells focuses on the use of energy cells that optimise supply with the local area; enera is working to develop a market for system services. The aim of DESIGNETZ is to simulate and develop predictive operation for the energy system. In addition to the exact type of information gathered, the technical design and the interfaces used, the data platforms also differ in terms of the user groups they address. The competition between the different approaches develops the way in which the individual platforms are fostered and facilitates the derivation of blueprints.