​Anyone connecting a battery to the grid before August 4, 2029 has so far been exempt from grid fees for 20 years. But this privilege is about to end. The regulatory authority has already made it clear: a permanent exemption from grid fees for battery storage is not sustainable.

This is causing uncertainty. Many project developers are currently trying to connect their storage systems to the grid before August 2029 to secure the fee exemption. The fear: after this date, grid fees could significantly worsen the business case.

But what is emerging now is not simply a “return to paying fees,” but a completely new grid fee system that will set new rules for storage.

The Federal Network Agency is currently publishing new position papers step by step, gradually outlining the future regime. One thing is clear: in the future, grid fees are intended not only to finance grid expansion, but also to actively steer flexible behavior – including storage.

This opens up new opportunities. In the future, storage can optimize not just for market prices, but also for grid value. And those who are flexible enough can benefit from the system rather than suffer from it.

1. The Most Important Questions for Battery Developers

Will batteries have to pay grid fees after 2029?

According to the Federal Network Agency – yes. The BNetzA has made it clear that the current exemption will not remain in place permanently. As the share of battery storage in the power system grows, they too will be expected to contribute to grid costs.

However, the final decision is still pending: possible transitional arrangements or changes to the methodology are still under discussion.

What grid fees are expected for standalone batteries?

From 2029, operators will face a new, significantly more complex fee system. A three-part model is planned:

• Grid connection fee (BKZ) will remain. As before, it is charged once when connecting to the grid.
• Financing tariffs will be split into:
• Capacity charges, based on the maximum connection capacity. There will be a choice component: operators can decide how much capacity to “reserve” and pay for accordingly.
• Energy charges, based on the actual energy flow – but only on the net self-consumption of the battery, essentially the RTE losses (as a so-called balancing tariff). If more energy is used than the chosen capacity allows, a penalty surcharge applies.
• Dynamic grid fees will be introduced as a new and separate element and could become a game changer:
• These tariffs apply to every kWh charged or discharged.
• Crucially: they can also be negative. Batteries that charge or discharge in a grid-friendly way could actually generate revenue instead of costs in the future.

What do the new grid fees mean for the battery storage business model?

The good news: the new fee system does not necessarily have to be a burden. For some projects, the changes could even open up additional income streams.

The real impact depends mainly on two factors.

• How high will the capacity and energy charges ultimately be?
• How much can be earned by optimizing around the dynamic tariffs?

In scenarios with low financing charges and for batteries in high-value locations (e.g., in grid congestion areas), storage could actually end up better off than today.

On the other hand, without the uplift from dynamic fees, revenues could be 3–10% lower, depending on the level of grid charges applied.

2. Financing Fees Increase OpEx

What is the logic behind balancing tariffs and how do they affect storage?

The basic principle: Only the self-consumption of the battery (RTE losses) is subject to financing grid fees, not the total energy charged or discharged. Storage is thus treated the same as other consumers.

What this means financially mainly depends on the energy charge and its future development: At the highest and high voltage levels, grid fees are forecast to remain largely stable until 2030. However, it remains uncertain whether the government will continue the current relief measures in the long term.

• Without subsidies, the price for 2026 would be around €66.50/MWh. If grid fees remain stable, we can expect a similar price in the future.
• With subsidies, the price is closer to €28.60/MWh.

For a 2-hour battery with 86% RTE, 2 cycles/day, and frequency reserve, this results in:

• Approx. 150MWh/MW/year as the battery's own consumption
• €4.3k–10k/MW/year in grid fees, depending on the fee level
• This corresponds to about 3–8% lower revenues.