Update on the MiSpeL Key Points: Metering Procedure for Demonstrating the Delineation Option
On 19 September 2025, the German Federal Network Agency (Bundesnetzagentur) published the key points on the market integration of storage systems and charging points (MiSpeL) for consultation. These drafts represent initial proposals, which will be discussed with the industry in a workshop on 1 October 2025. The final ruling may therefore deviate from the current key points. The new regulations aim to ease the existing restrictions on the use of PV-storage combinations. At present, operators must choose between EEG funding for temporarily stored solar power or the flexible use of the storage system. The exclusivity option only permits the storage of self-generated electricity, while any grid supply used to charge the storage system terminates the entire eligibility for funding. The MiSpeL key points propose two new options intended to enable the simultaneous use of EEG funding and levy advantages. This could open up new economic opportunities for PV-storage operators, such as charging when electricity prices are low and discharging when prices are high. The consultation period runs until 24 October 2025. The Federal Network Agency will then evaluate the comments received and draw up the final ruling.
What is the MiSpeL ruling?
The market integration of storage systems and charging points (MiSpeL) is a planned ruling by the Federal Network Agency, based on the changes to the Renewable Energy Sources Act (EEG) and the Energy Financing Act (EnFG) introduced by the Peak Electricity Act (Stromspitzengesetz). These legislative changes have created the legal basis for more flexible use of electricity storage systems and bidirectional charging points.
The core problem lies in the current exclusivity option under Section 19 (3a) EEG. While this permits EEG funding for electricity from "pure renewable-energy electricity storage systems", it simultaneously prohibits the storage of grid electricity. As soon as grid electricity is charged into the storage system even once, the entire eligibility for funding lapses for all subsequent feed-ins. Conversely, claiming EEG funding rules out levy netting.
In practice, this strict separation means that storage systems are either completely blocked against grid electricity or decoupled from grid feed-in. The Federal Network Agency notes that, as a result, "the flexibility potential of electricity storage systems and charging points has so far been used only to a very limited extent in practice, and opportunities to actively respond to market signals remain untapped”. [1]
MiSpeL is intended to resolve this deadlock through two new options: the delineation option for precise quantitative allocation and the flat-rate option for simplified blanket rules. Both options are intended to enable bidirectional storage use while proportionally retaining funding and levy advantages.
The ruling is intended to apply equally to new and existing systems. However, both new options require full allocation to direct marketing. A combination with the classic feed-in tariff is excluded. The flat-rate option is additionally subject to state-aid approval by the European Commission.
The three options at a glance
The MiSpeL key points provide for three different marketing models from which system operators can choose. Each option has specific characteristics, requirements and areas of application.
Exclusivity option (existing)
The established exclusivity option remains in its current form. It follows the principle of strict separation: either the storage system is charged exclusively with self-generated renewable electricity and receives full EEG funding for it, or it is used for other purposes and loses all eligibility for funding.
In practice, this usually requires the storage system to be technically blocked either against grid electricity during charging or against grid feed-in during discharging. The advantage lies in simple accounting and the full funding rate for the electricity fed in. The main disadvantage is the lack of flexibility: market responses to price fluctuations – and thereby charging when electricity prices are low and discharging when they are high – are not possible.
This option continues to be suitable for operators who value simple structures and maximum planning certainty, but who forgo extended optimization options.
Delineation option (new)
The delineation option enables fully flexible mixed operation but requires precise, quantitative evidence. Storage systems can be charged with both solar and grid electricity, while EEG funding and levy advantages are retained proportionally.
The system is based on quarter-hourly recording of all electricity flows and their mathematical allocation according to defined formulas. Two basic rules govern the allocation: simultaneous grid electricity takes priority for storage charging/consumption, and simultaneous storage generation takes priority for grid feed-in.
Storage generation is the electricity that the battery storage system releases again (discharges).
Storage consumption is the electricity that the battery stores (charges).
The delineation option requires elaborate metering technology with several quarter-hour-accurate meters and is available for all system sizes. It offers maximum economic optimization, but entails considerable complexity in accounting.
Flat-rate option (new)
The flat-rate option simplifies the allocation logic through blanket rules, but is limited to solar systems of up to 30 kWp and requires state-aid approval from the EU Commission.
The basic principle uses a fixed limit: per kWp of installed solar capacity, a maximum of 500 kWh of grid feed-in per year is considered eligible for funding in principle. If the actual feed-in is below this limit, it is fully eligible for funding. If it exceeds the limit, the surplus is treated as a flat rate as levy-privileged "temporarily stored grid electricity".
The flat-rate option requires only a single bidirectional meter and dispenses with complex calculations. It is aimed primarily at typical prosumer households that wish to benefit from the simplification.
The delineation option in detail – summary
Core principle
The delineation option enables the flexible, bidirectional use of electricity storage systems and charging points with renewable-energy systems through mathematically precise allocation of electricity flows based on quarter-hourly measured values.
Main advantages over the previous exclusivity option
Mixed operation possible: electricity storage systems can charge both renewable electricity and grid electricity
Bidirectional charging points: electric vehicles can act as storage
Parallel privileges: EEG funding and levy netting can be used simultaneously
Market orientation: charging when prices are low, discharging when prices are high
Central allocation rules (set by law)
Storage consumption: simultaneous grid electricity takes priority over renewable electricity when charging
Grid feed-in: simultaneous storage generation takes priority over direct renewable feed-in
Calculating the shares (core formulas)
Grid electricity share for the year:
Grid electricity share = sum of simultaneous grid electricity consumption / total consumption in the storage system
Nettable grid feed-in:
Nettable = grid electricity share × sum of simultaneous storage feed-in
Fundable grid feed-in:
Renewable electricity share = (100% - grid electricity share) Fundable = renewable electricity share × storage feed-in in AW>0 periods + direct renewable feed-in in AW>0 periods
Detailed calculations
An interactive Google Sheet with all formulas and practical examples is available for a precise calculation via the following link. The input values can be adjusted to simulate different scenarios and to understand the effects on funding and levy privileges: https://docs.google.com/spreadsheets/d/1B17LnAejtV2epoKLl6zyqYW1TtS0c2Yp7Mvwhcyc0I8/edit?usp=sharing
Metering requirements in case A1
The delineation option requires at least two quarter-hour-accurate bidirectional meters:
Z1: recording grid supply and grid feed-in
Z2: recording storage consumption and storage generation
A third meter may be required for the separate recording of privileged storage losses. All measurements must be carried out in compliance with metering and calibration law at a quarter-hourly resolution.
The delineation option enables maximum flexibility in storage management, but requires considerable technical and administrative effort. It is particularly suitable for larger systems and operators who want to exploit the full optimization potential.
[1] Consultation: https://www.bundesnetzagentur.de/DE/Fachthemen/ElektrizitaetundGas/ErneuerbareEnergien/EEG_Aufsicht/MiSpeL/DL/Konsultation.html?nn=1067830
More Articles
MiSpeL Becomes Binding: Determination from October 2026, Transitional Phase until September 2027
Aging: Why Charging and Discharging an Industrial Battery Storage System for Arbitrage Doesn't Always Pay Off
Balancing Group and Balancing Energy: Why Storage Projects Lose Economic Viability During Operation
Why the dynamic rate plan is the first step toward flexible marketing, and what else you need
Trading spare capacity: how your battery earns money on the spot market on the side
Plant Certificates for Battery Storage: When You Need One, What It Costs, and How the Process Works