In September 2025, in our post “MiSpeL: More Market & Opportunities for Large-Scale Storage”explains what the reform means and what options it opens up for large-scale storage. Since then, the process has evolved further – and the central question in conversations with industrial customers is now almost always: When can I expect this, and what do I need to prepare in the meantime?
This post provides a clear answer based on the current procedural status (May 2026) and derives concrete recommendations for operators of large-scale battery storage systems.
The official schedule of the Federal Network Agency
The MiSpeL determination is not a single legislative act, but a multi-stage regulatory process. The Federal Network Agency (BNetzA) carries it out based on its powers under Section 85d of the EEG 2023. Here's an overview of all the essential milestones:
| Moment | Milestones |
| February 25, 2025 | "Power peak law comes into effect (EEG § 19 Para. 3b and 3c)" |
| July 2025 | BNetzA opens the MiSpeL (Ref. No.: 618-25-02) designation procedure |
| September 18, 2025 | Publication of the draft determination for public consultation |
| October 24, 2025 | End of consultation period - industry associations call for H1/2026 entry into force |
| January 1, 2026 | Abolition of double grid charge burden for fed-back electricity (EnWG Amendment) |
| March 17, 2026 | Definition of mathematical rules and measurement specifications for mixed operation |
| June 30, 2026 | End of the statutory deadline for the legal finality of the MiSpeL determination |
| 5. August 2026 | Veröffentlichung des Arbeitsstandes |
| 1. Oktober 2026 | Actual entry into force and start of the implementation obligation for the determination contents |
| January 1, 2027 | Start of billing via standardized, fully automated market communication |
Die gesetzliche Frist war bis zum 30. Juni 2026 ausgelaufen. Branchenverbände wie der bne (Bundesverband Neue Energiewirtschaft) forderten eigentlich ein früheres Inkrafttreten noch im ersten Halbjahr 2026, um Einspeisespitzen im Sommer 2026 abzufedern. Jetzt ist der 1. Oktober für das Inkrafttreten der MiSpel-Festlegung vorgesehen.
What “finality” really means here – an important distinction
Many market participants equate “legal force of the determination” with “immediately applicable.” This is a mistake that can lead to miscalculations in investment planning.
Legal force ≠ immediate applicability
Selbst wenn die Festlegung zum 1. Oktober 2026 in Kraft tritt, greifen die neuen Optionen nicht automatisch direkt ab Oktober. Zusätzlich sind erforderlich:
- EU State Aid Approval (pending, especially for the demarcation option)
- Technical implementation by network operators and metering point operators
- Adapting market communication processes
The full implementation obligation for all grid operators is officially planned from January 1, 2027. During a transition phase between the entry into force of the law and full operation, bilateral coordination with grid operators will be the norm, not the exception.
For BESS operators, this means: The new Accrual option (§ 19 Paragraph 3b EEG and § 21 Paragraphs 1 to 4 EnFG), the only economically relevant option for plants from 1 MWh onwards, can be used in regular operation at the earliest from the beginning of 2027 – and even then, only with timely EU approval.
Why industry associations are pushing for swift enactment
The pressure on the BNetzA comes from multiple directions – and it is justified:
- Network stability Input tips: Without MiSpeL Co-Location BESS do not use the stored green electricity in a market-optimized way. This increases the risk of negative electricity prices and curtailment.
- Investment Security Missing investment basis: Project developers and industrial customers hesitate with new Battery storage-Investments as long as the regulatory framework is not yet final.
- Parallel Relief Additionally, the EnWG amendment, effective January 1, 2026, abolishes the double network charge burden for stored power fed back into the grid. This step is already legally binding and immediately improves the economic viability of large-scale storage systems.
What large-scale storage operators need to do now
The period until entry into force is not a passive waiting phase. Those who already operate a large battery storage system and want to seamlessly switch to MiSpeL operation from the outset in 2027 must act today – particularly in three areas:
Prepare measuring equipment
The demarcation option requires two smart metering systems with 15-minute intervals: one for the PV feed-in, one for grid power draw by the storage. These systems must be commissioned and installed by the responsible metering point operator – in practice, this takes several months.
2. Check direct sales structure
The prerequisite for using both new options is the direct marketing of the generated electricity. Those who still charge according to the fixed feed-in tariff must check whether and when a change makes sense. This also applies to the flat-rate option – although it is economically hardly relevant for large storage systems (from approx. 1 MWh) as it is limited to systems up to 30 kWp.
3. Don't miss Section 118, Paragraph 6 of the EnWG
Parallel to MiSpeL, there is a time-sensitive funding regulation: The Network surcharge exemption According to §118 Paragraph 6 of the EnWG, for battery storage systems put into operation before August 4, 2029, this applies for 20 years. Given a planning lead time of 6 to 12 months, project development should begin at the latest now.
What remains open – and what risks investors should be aware of
MiSpeL creates planning certainty, but not completely. Three points remain unresolved as of today (May 2026):
- EU state aid approval: A specific date is not yet known. Without it, the new flat-rate option for PV systems up to 30 kWp, storage systems and/or charging points as well as other consumption behind the feed-in or withdrawal point cannot be applied.
- Network charge reform: How the AgNes Grid Fees 2029 Calculation is still pending. Questions regarding the network charge privileging of storage facilities are the subject of a separate BNetzA procedure.
For investors in large-scale storage projects, this means: MiSpeL is a necessary but not sufficient step. The overall economic calculation also depends on the outcome of the AgNes determination.
Conclusion: Preparation now, market launch 2027
MiSpeL wird mit hoher Wahrscheinlichkeit ab dem 1. Oktober 2026 rechtskräftig. Der praktische Marktbetrieb – insbesondere für die Abgrenzungsoption, die für Großspeicher entscheidend ist – startet realistischerweise Anfang 2027. Die Vollautomatisierung der Marktkommunikation folgt ab April 2027.
The window for preparing existing battery storage systems is narrow. Those who tackle the measurement technology, direct marketing structure, and project planning (including §118 EnWG) now can benefit from day one in 2027. Those who wait risk not only missed revenue potential but also bottlenecks with metering point operators and grid operators, who will be in high demand during the implementation phase.
Now is a good time for new BESS projects. The prerequisites for technology, metering points, and EMS are in place, and the window until August 2029 is still open.