The Redispatch is the central mechanism to ensure the stability of the electrical supply system. Unlike pure Roof covering, which aims to balance generation and consumption in terms of quantity, redispatch aims to, Grid bottlenecks to be avoided. Background: Electricity does not physically flow along market paths, but rather through the lines that offer it the least resistance according to the laws of electrical engineering. This can lead to individual network sections being overloaded, even if there are sufficient capacities in the overall system.
During redispatch, grid operators specifically intervene in the operational planning of power generators—and increasingly, flexible consumers and storage facilities. For example, they reduce feed-in before an overloaded grid section and increase it behind that bottleneck. This redirects power flows without significantly changing the total amount of energy generated.
In practice, redispatch is therefore not an „emergency shutdown,“ but rather a planned, often calculated on a daily basis Bottleneck management. It is used both in Day-Ahead Trading (Planning for the next day) as well as short-term Intraday and real-time operation used.
With the growing share of volatile generation from wind and photovoltaic systems and the delayed grid expansion, the importance of redispatch is continuously increasing. It has become an indispensable tool to Security of supply to ensure and at the same time to drive forward the transformation of the energy system.
From Redispatch 1.0 to 2.0
The first version of Redispatch was available in Germany from around 2010. It originally served exclusively as a control instrument for Conventional large power plants with a power from 10 MW. The basis was formed by § 13 EnWG and the grid and system rules of the transmission system operators (TSOs). The process was comparatively manageable: the TSOs identified bottlenecks, coordinated with the affected power plant operators, and adjusted their schedules. The interventions were primarily carried out in Day-Ahead Period and were coordinated regarding the power plant deployment plan.
The transition to Redispatch 2.0
However, with the increasing share of renewable energies and the changed flow directions in the transmission grid, the need for congestion management measures increased significantly. Even before 2020, regularly several terawatt-hours per year reallocated – with rising costs in the three-digit million range. Therefore, the expanded mechanism came into effect in October 2021 Redispatch 2.0 in Kraft. The central change:
- Integration of renewable and CHP plants from 100 kW into the redispatch process.
- Obligation to provide Feed-in forecasts, Non-availability messages and remote controllability.
This made redispatch an instrument that spans grid levels, including not only large conventional power plants but also thousands of smaller installations in distribution grids. In addition to the TSOs, since then also Distribution network operator actively involved in the coordination.
Regulatory Framework
The redispatch is embedded in a web of laws and regulations, including:
- Energy Industry Act (EnWG) - legal basis for grid and system security measures.
- Measures Ordinance Electricity – Specification of Permitted Interventions.
- Energy Grid Expansion Act (EnLAG) – Strategic Context within Grid Expansion.
- Market Participant Registry (MaStR) – central database for plant master data.
Cost Development & Importance
The expansion of redispatch measures led to a significant Increase in interventions and costs.
- 2021: Redispatch costs in Germany exceeded 600 million euros – a record high.
- Since then: Upward trend, as grid bottlenecks and volatile feed-in are increasing. In 2022 and 2023 alone, the costs reached approximately 2.5 billion euros annually.
This means redispatch is no longer a rarely used special instrument, but rather a Permanent tooling for grid operations – with increasing dependence on the technical and organizational interplay of all market participants.
Technical & Organizational Processes for Redispatch
The redispatch process is a finely tuned interplay of forecasts, grid calculations, control commands, and balance settlement. The entire process is highly data-driven and relies on standardized communication processes between grid operators, direct marketers, balancing responsible parties, and plant operators.
Forecasting phase
The forecasting phase comes first. Here, plant operators or their direct marketers provide predictions about the expected electricity feed-in. For renewable energies, this is usually based on meteorological data and corresponding weather models. In parallel, grid operators create consumption forecasts for their supply areas. Both data streams are merged to obtain the most accurate overall forecast possible. These forecasts are crucial because any deviation can lead to incorrect planning assumptions and thus to unnecessary interventions or, in the worst case, to grid overload.
2. Network Security Calculation
Based on these predictions, the grid operators perform a grid security calculation. This involves the anticipated power flows for the upcoming day – and in the Intraday Trading even continuously – simulated. This simulation takes into account both the physical conditions of the grid topology and possible restrictions due to maintenance or grid disruptions. If the calculation shows that certain line sections could be overloaded, redispatch is triggered.
3. Planning
The plan then specifies which plants should reduce their feed-in („curtailment“) and which should increase it („ramp-up“). Not only the purely physical conditions play a role, but also economic criteria. For example, those producers are often used first whose adjustment causes the lowest costs or whose influence on the market price is minimal. Ideally, this happens automatically via optimization algorithms that weigh various proposed measures against each other.
4. Retrieval Phase
Once the planning is complete, the retrieval phase begins. The corresponding signals are transmitted to the systems via remote control technology – such as radio control receivers, IP-based control boxes, or direct SCADA connections. Depending on the urgency, the retrieval is for the following day or carried out during ongoing operations with very short response times. The technical reliability of this communication is a critical success factor, as a delayed or unimplemented measure would leave the bottleneck unchanged.
5. Accounting
After implementation, the balancing settlement follows. Here, the deviations from the original schedules caused by redispatch are determined and compensated among the participating market players. For plant operators, this generally means a compensation payment, the amount of which is based on lost revenues. The balancing settlement is complex because it considers both the physical and economic consequences of the intervention and, in many cases, affects multiple grid and market roles.
Redispatch is therefore far more than a simple control command – it is a consistently networked process that focuses on data quality, IT interfaces, and reaction speed. Without automation and standardized procedures, the current level of intervention would hardly be manageable anymore.
Platforms & IT Infrastructure for Redispatch
The coordination of redispatch measures would be impossible without specialized IT platforms and standardized data processes. In Germany, an ecosystem of central, decentralized, and hybrid solutions has been established in recent years. These are predominantly cloud-based and ensure information exchange between all involved grid and plant operators. The various platforms are the technical backbone of congestion management – they consolidate data, calculate grid flows, optimize measures, and transmit control commands.
Data Coordination & Models
A central feature is the distinction between centralized and decentralized coordination. In the centralized variant, all grid-relevant data – from congestion notifications and flexibility offers to price information – flow to a common platform that takes over measure planning across all grid levels. Examples include the DA/RE (DAta exchange/Redispatch) platform and the comax platform from the research project C/sells. The advantage lies in unified optimization across all grid levels, which enables efficiency gains, especially in complex congestion situations with many participants.
Decentralized coordination, on the other hand, relies on each grid operator performing the grid security calculation for their own area and passing the results to upstream or downstream operators. This „bottom-up“ approach offers the advantage that local conditions can be taken into account more precisely. However, it is more dependent on the quality and speed of data transmission and requires clearly defined interfaces.
Interfaces
Therefore, standardized interfaces and formats are a particularly important building block. APIs and market-wide defined data models – for example, within the framework of Connect+ – ensure that even heterogeneous IT systems can communicate with each other. Legacy systems such as SAP-IS-U or SIV are often connected via integration platforms so that the existing process landscapes of network operators do not have to be completely changed. In this way, redispatch communication can be integrated into both classic network control systems and modern cloud-based applications.
Automation & Security
The platforms themselves offer increasingly automated functions: forecasting engines process weather, load, and generation data in real-time, optimization algorithms calculate the most efficient bottleneck measures, and call-offs are automatically triggered via the appropriate communication channels. Billing processes can also be automated in many cases, reducing manual steps and potential for errors. Given the system-critical role of these platforms, high demands are placed on IT security, availability, and reliability. Many operators follow the principle of „Resilience by Design,“ where redundancy, contingency plans, and cybersecurity measures are integrated into the system architecture from the outset. Furthermore, interoperability is taken into account to ensure that different platforms and grid operator processes harmonize with each other.
Communication & Control of the Systems
The actual implementation of redispatch measures stands or falls with the technical possibility of controlling plants safely, quickly, and precisely. In practice, this means that generation plants, storage systems, and, in some cases, controllable consumers must be connected to the grid or direct marketing systems via suitable interfaces.
From Analog to Digital Control
Historically, many plants were integrated using radio remote control technology (FRT). This method is robust and relatively simple, but it has limitations in data transfer rate and flexibility. With increasing complexity of redispatch requirements—such as more frequent calls, stepped power reductions, or short-term schedule adjustments—purely analog control paths are reaching their limits. Therefore, more and more operators are opting for digital control solutions. In this approach, the plants are connected via IP using mobile communications or the internet, enabling bidirectional communication. This makes it possible to transmit not only control commands but also operating data and feedback on the plant's current performance status.
Protocols & Storage
The technical implementation usually takes place via Telecontrol technology or control boxes that support standard protocols such as IEC 60870-5-104 or IEC 61850. This allows for seamless integration of queries into grid control and marketing systems. Storage systems play a special role here: they can relieve bottlenecks by precisely charging or discharging in both directions with second-level accuracy. The control of Large battery storage systems particularly precise planning specifications, as their loading and unloading cycles are time-limited and economically optimized.
Communication Logic & Monitoring
Besides the hardware, communication logic plays a crucial role. The dispatch signals usually follow a hierarchical structure: first, the measure is determined via the central or decentralized redispatch platform, then it is passed on to the responsible grid operator or direct marketer, and finally sent as a control command to the plant. This process must be designed to minimize latency, especially for short-term intraday adjustments that need to take effect within minutes. For regulatory reasons, every dispatch must be traceable. Monitoring when which plant received and implemented which command requires flawless data collection, also for later balancing or error tracing.
Challenges & Potentials in Redispatch
The redispatch process faces several challenges: Data quality and availability are often insufficient, especially for small or older plants. Different IT systems and a lack of standardized interfaces complicate automated control and increase manual effort. Short-term bottlenecks require rapid response times, which are not always guaranteed at present. Furthermore, complex billing and delayed payments lead to dissatisfaction among plant operators.
At the same time, great opportunities arise from the introduction of standardized interfaces, cloud-based platforms, and the use of artificial intelligence for better forecasting and control. The integration of decentralized flexibilities such as storage and controllable loads can help to avoid grid bottlenecks and make redispatch more efficient. Through further technical, organizational, and regulatory improvements, redispatch can become more reliable, cost-effective, and user-friendly in the future.
Future of Redispatch
Redispatch will continue to evolve and adapt to the challenges of the energy transition. A key driver will be the increased digitalization and automation of grid control. State-of-the-art platforms and new standards will ensure greater efficiency. The role of decentralized energy facilities and flexibilities will also continue to grow. Battery storage, electromobility, and controllable loads will be increasingly integrated into redispatch to mitigate grid bottlenecks early on and relieve the burden on grid expansion. Virtual power plants and aggregators will play a key role in this by bundling and coordinating many small facilities.
Furthermore, the increased integration of artificial intelligence and data-driven algorithms will improve forecast accuracy and control quality. However, regulatory adjustments are also necessary. To promote transparency, fairness, and acceptance, the harmonization of billing processes and the introduction of automated balance settlements should be advanced.
Conclusion
Redispatch is an indispensable tool for avoiding grid bottlenecks and ensuring the stability of the German power supply – especially in the context of the energy transition and the increasing share of renewable energies. With the further development to Redispatch 2.0, the range of involved facilities has been significantly expanded, which, however, brings new technical and organizational challenges.
The future of redispatch lies in greater digitalization, automation, and integration of decentralized flexibilities. Modern IT platforms, standardized interfaces, and intelligent control systems will make the process more efficient and transparent. At the same time, regulatory adjustments are necessary to improve acceptance and economic viability for all stakeholders.