Grid Congestion Management 2025: Power Grid Stable, Costs Slightly Up Amid Strong Renewable Expansion
Bonn (Germany) - The expansion of renewable energy combined with limited grid capacity makes congestion management indispensable. In 2025, the volume of measures remained stable, while costs increased slightly. Overall, more than 96% of renewable electricity was fed into the grid. This is based on an analysis by SMARD, the German electricity market information platform of the Federal Network Agency.
Quarterly balance Q4 2025 - Efficient control despite regional differences
In the fourth quarter of 2025, the volume of measures fell by around 9% to 9,531 GWh (Q4 2024: 10,427 GWh). At the same time, costs declined by 18% to €885 million (Q4 2024: €1.08 billion). According to the SMARD report, the reduced curtailment of offshore wind was largely due to the exceptionally high redispatch demand in Q4 2024, caused by a pronounced wind front in December.
Of the measures in Q4, 2,552 GWh were attributable to renewable energy installations and 2,002 GWh to conventional power plants. Around 71% of congestion occurred in the transmission grid, with 29% in distribution networks. Curtailments affected about 4% of renewable generation, meaning the majority of electricity produced could still be fed directly into the grid.
To compensate for reductions, conventional market-based power plants were ramped up by 2,653 GWh, a decrease of around 15% compared to Q4 2024 (3,042 GWh). The volume of measures involving reserve power plants amounted to 532 GWh, also significantly lower than in Q4 2024 (796 GWh). This development is attributable to the decline in negative redispatch, resulting in fewer balancing measures and less need to increase generation.
Annual balance 2025 - Overall stable development
For the full year 2025, the total volume of congestion management measures remained virtually unchanged at 30,319 GWh (2024: 30,318 GWh). Redispatch measures involving renewable energy installations totaled 9,379 GWh, also stable (2024: 9,389 GWh).
Within renewables, the distribution shifted: offshore wind declined by 27% to 3,351 GWh (2024: 4,565 GWh), onshore wind decreased slightly to 3,225 GWh (2024: 3,394 GWh), while photovoltaic curtailment rose significantly to 2,704 GWh (2024: 1,394 GWh). According to the SMARD report, this increase in photovoltaic redispatch was driven by nearly 10 GW of new capacity additions and above-average solar radiation in spring and summer.
The most frequently ramped-up plants were natural gas and hard coal plants, each contributing 4,143 GWh, followed by lignite at 851 GWh.
The share of congestion in distribution networks rose to 35% (2024: 26%). This reflects the growing expansion of decentralized generation, which increasingly burdens lower grid levels. As a result, congestion is shifting from transmission lines to distribution networks.
Cost structure, reserve deployment and countertrading
In 2025, curtailment of renewable energy accounted for 3.5% of total renewable electricity generation. This means that more than 96% of renewable energy could be fed into the grid and used by end consumers.
Total congestion management costs rose by around 4% to €3.071 billion (2024: €2.954 billion). Of this, €1.176 billion was attributable to redispatch measures involving conventional power plants (2024: €1.233 billion). Financial compensation for curtailed renewable installations amounted to €433 million, around 22% lower than the previous year, as higher wholesale prices reduced market premiums (2024: €554 million).
Preliminary capacity and fixed costs for reserve power plants reached €952 million in 2025 (2024: €696 million). Operating costs amounted to around €407 million (2024: €372 million), bringing total reserve-related costs to approximately €1.36 billion. Countertrading measures accounted for €102 million.
Source: IWR Online, 01 Apr 2026