Electricity Grid Fee Structure: Model Proposals from BNetzA & BDEW

Two model proposals are on the table for reforming the General Electricity Grid Fee Structure in 2029. While both address the same overarching requirements, they differ considerably in their priorities. The models proposed by the Federal Network Agency (BNetzA) and the BDEW for the future electricity grid fee system differ in four key areas: static components, dynamic components for congestion management, handling of capacity overruns, and the integration of low-voltage customers with smart metering systems (iMSys).

In the study “Grid Fee Criteria in the Context of Adjustments to the General Electricity Grid Fee Structure – A Comparison of the BNetzA and BDEW Grid Fee Models with Regard to Consumers,” the Institute of Energy Economics (EWI) compares the ongoing consumer grid fees of both models using seven criteria, commissioned by the German Association of Energy and Water Industries (BDEW). The study also reveals the implicit weighting of criteria underlying each model.

Four model differences shape the comparison

The comparison centres on four differences: the static components, the dynamic components for congestion management, the handling of capacity overruns, and the integration of low-voltage customers with smart metering systems (iMSys). An additional question is whether a minimum capacity would be mandatory under the BNetzA model.

The BNetzA model combines a capacity price with two energy prices (AP1 within, AP2 above the booked capacity) and a dynamic energy price (AP3) in congestion situations. The BDEW model, by contrast, provides for a guaranteed capacity (GC), an optional capacity (OC) that the grid operator may temporarily restrict, and an overrun charge (OC) as a penalty. The two models thus follow different logics in handling peak loads and congestion.

BNetzA and BDEW weight criteria differently

The analysis shows that the two models set different priorities. The BNetzA model places greater emphasis on congestion management at the transmission grid level, while keeping distributional effects smaller relative to the current grid fee structure. The BDEW model, by contrast, more strongly addresses economic predictability, cost-reflectiveness, grid-compatibility at the distribution grid level, and comprehensibility for grid customers. Both models therefore tackle different challenges of the future electricity system.

Parametrization determines real-world impact

Whether the model priorities translate into real-world effects depends substantially on the specific parametrization. For example, the level and ratio of capacity, energy, and overrun prices determine the incentives for grid-compatible load shifting and the distributional effects between consumer groups.

It is therefore essential for the 2029 introduction to determine the parametrization alongside the desired model priorities. In the longer term, the framework should also be able to respond to changes in the electricity system, such as increasing load-driven distribution grid congestion or new flexibility options.