FAQ

What is the objective of the instrument?

When grid capacity is insufficient to transport renewable electricity generation, grid operators must curtail renewable energy (RES) plants (a “traditional” redispatch measure). The “Use Instead of Curtail” mechanism creates incentives to activate additional electricity consumption in regions with a surplus of renewable energy (relief regions) in order to counteract emerging grid constraints.

The objective of “Use Instead of Curtail” is to reduce the amount of renewable electricity that must be curtailed due to grid bottlenecks.

How is this aim to be achieved?

The transmission system operators carry out a forecast of the hourly curtailment electricity volumes for relief regions on the morning of the previous day. Partial quantities of this forecast are allocated to additional connectible consumers or electricity storage facilities, whose load increase contributes to reducing the forecast grid congestion. Participants benefit from lower electricity costs for the allocated curtailment electricity volumes (see category "Benefits of participation" below).

When does the instrument start? What does the "trial phase" consist of?

The instrument started on 1 October 2024 with a two-year pilot phase. During this phase, the forecasted curtailed electricity volumes are allocated through a simplified flat-rate allocation procedure. The Implementation Concept 1.0  dated 01 April 2024 and the contractual documents dated 01 August 2024 describe the modalities of this pilot phase.

From October 2026 onwards, the flat-rate allocation procedure will be replaced by a competitive tendering process. Accordingly, the Implementation Concept and the associated Contractual Documents have been updated.

What are "relief regions" and what do they look like?

Relief regions are geographical areas in which additional controllable loads can effectively reduce renewable energy curtailment caused by grid constraints.

For the pilot phase, the TSOs designated eight relief regions:

The curtailed electricity volumes are forecast daily for each region and allocated to participating controllable loads within the same region.

For the period beginning on 1 October 2026, the Transmission System Operators (TSOs) have retained the eight existing relief regions and expanded them to include additional districts:

The exact definition (list of districts) of the relief regions can be found in the Implementation Concept.

For example, future changes in the (expected) grid topology may require adjustments to the boundaries and number of relief regions (e.g., due to grid expansion as part of the energy transition). Should such adjustments become necessary, they will be communicated six months in advance.

Do DSOs also conduct their own tenders?

At present, Distribution System Operators (DSOs) do not conduct their own tenders. Currently, this is a TSO-only mechanism. However, the use of this mechanism does not necessarily have to remain limited to TSOs.

How often can allocations of curtailed electricity volumes be expected?

This varies significantly between the individual relief regions. Depending on the region, the TSOs expect between 700 and 2,100 activation hours per year. Under the Compensation parameters, the TSOs publish the expected activation hours for each region for the respective calendar year.

The activation hours show strong seasonality. The TSOs expect that a large proportion of activations will occur during the winter period from October to March due to wind-driven congestion management requirements. At the same time, increasing impacts and congestion management needs, particularly during the summer months, are becoming relevant due to photovoltaic generation feed-in.

Wind-driven activations tend to be relatively long in duration. Approximately half of all “Use Instead of Curtail” allocation windows last four hours or longer.

The curtailed electricity volumes published since October 2024 can be used for internal economic analyses: Data Publications (Curtailed Electricity Volumes).

How does the instrument differ from Redispatch?

Redispatch involves adjustments to the feed-in schedules of generation plants and storage facilities requested by grid operators on the evening before delivery and within the intraday timeframe in order to resolve grid constraints. “Use Instead of Curtail” differs from redispatch in several key aspects:

• Earlier intervention: Additional electricity consumption is instructed on the morning of the previous day in order to reduce emerging grid constraints. This reduces the subsequent need for redispatch measures.
• Load-based approach: “Use Instead of Curtail” enables electricity consumers to contribute to reducing renewable energy curtailment. Such consumers are currently excluded from the redispatch process.
• Voluntary and not cost-neutral: Unlike redispatch, participation in the “Use Instead of Curtail” mechanism is voluntary. The allocation of curtailed electricity volumes is not financially neutral and may result in financial gains for participants.

What is “additional electricity consumption”? Which technologies can participate?

The Federal Network Agency (Bundesnetzagentur) defined the additionality criteria in its determination of 28 June 2024 and distinguishes between three categories of eligible technologies:

• Segment 1: Substitution of Fossil Heat Generation
• Segment 2: Grid-Connected Electricity Storage Facilities
• Segment 3: Electrolysers and Large Heat Pumps

Each segment is subject to its own specific criteria that must be fulfilled by the plant operator.

Detailed requirements can be found in the BNetzA Determination of Additionality Criteria. Compliance with these criteria is verified by the TSOs as part of the prequalification process.

Can existing plants participate, or must the plant be newly built?

For facilities in Segment 3 ("Electrolysers and Large Heat Pumps"), commissioning must have taken place after 29 December 2023.

This restriction does not apply to Segment 1: “Substitution of Fossil Heat Generation” and 2: “Grid-Connected Electricity Storage Facilities”. Existing plants are therefore eligible to participate in these two segments.

Do geographical criteria apply?

Yes. Participation is linked to the geographical location of the facility. The facility must be located within a relief region defined by the TSOs (i.e. the postal address of the market location must be within the relief region). The exact relief regions can be found in the section above entitled “What are relief regions and what do they look like?”

Can small facilities participate?

Yes. Small facilities connected to the distribution network may participate regardless of voltage level or individual plant size. However, very small facilities (< 100 kW) must be aggregated into a pool. The net rated capacity of a pool must be at least 100 kW, and all participating facilities must be located within a relief region.

Is a separate meter required?

Pursuant to Section 13k (6) No. 3 EnWG, a separate withdrawal point is required for the allocated curtailed electricity volumes. No electricity may be withdrawn from this withdrawal point to supply other consumption units or storage facilities. In the terminology of market communication, this corresponds to a dedicated Metering Location (MeLo). Furthermore, separate balancing is required, which necessitates a dedicated Market Location (MaLo). Compliance with these requirements must be demonstrated during prequalification by providing an appropriate metering concept.

My facility is only available seasonally during the heating period. Can I still participate?

Yes. Seasonal availability must be reported to the connecting TSO during the prequalification process. During periods in which the facility is unavailable, participants must continuously report a “Use Instead of Curtail” potential of 0 MW (see the question below: “What are the key process steps?”).

What special criteria apply to facilities in Segment 1 (“Substitution of Fossil Heat Generation”)?

For facilities within Segment 1 (see the BNetzA Determination on Additionality Criteria), electricity consumption outside allocated curtailed electricity volumes is generally not permitted. The following exceptions apply:

• Monthly consumption up to 2% of full-load operation
• Consumption during start-up and shut-down ramps (these must be declared during prequalification)
• Provision of balancing energy services

In addition, all power-to-heat facilities feeding into the same heating network and capable of fulfilling the additionality criteria are required to participate in the “Use Instead of Curtail” scheme.

What special criteria apply to facilities in Segment 2 (“Grid-Connected Electricity Storage Facilities”)?

Grid-connected electricity storage facilities must be metered and balanced separately from any additional consumption or generation (i.e. they require a dedicated market location).

Electricity consumption outside allocated curtailed electricity volumes is generally not permitted. The following exceptions apply:

• Monthly consumption up to 2% of full-load operation
• Provision of balancing energy services
• Consumption required for the provision of balancing reserves (e.g. achieving the necessary state of charge)

In addition, storage facilities are subject to a generation ban during forecast congestion periods. These periods are published on Netztransparenz.de at 10:00 a.m. on the preceding day. An exception exists for the provision of Frequency Containment Reserve (FCR).

The following restrictions therefore apply to participating storage facilities:

What special criteria apply to facilities in Segment 3 (“Electrolysers and Large Heat Pumps ≥100 kW”)?

Facilities within Segment 3 must:

• Have been commissioned after 29 December 2023
• Have a minimum rated capacity of 100 kW
• Unlike the first two segments, the operational use of these facilities is not subject to additional restrictions.

Is it possible to provide balancing reserves with facilities participating in “Use Instead of Curtail”?

In principle, yes, but not simultaneously. Balancing reserve services may only be provided during periods in which no curtailed electricity volume has been allocated to the facility. Additional requirements apply to electricity storage facilities (see the question above: “What special criteria apply to facilities in Segment 2 ‘Grid-Connected Electricity Storage Facilities’?”).

In conjunction with the reporting of “Use Instead of Curtail” potentials at 07:00 a.m. on the preceding day (see the “Operational process” description below), this means that participants must independently decide on the previous day whether they wish to market their capacity on the balancing reserve market or offer it under the “Use Instead of Curtail” mechanism.

What is the basic process for tendering and remuneration?

One month before the start of a calendar year (or one month before the start of competitive tenders from 1 October 2026 onward), the TSOs determine a minimum price, a price cap, and an electricity-related ancillary cost compensation limit applicable to all participants for the respective calendar year. The currently applicable Compensation Parameters can be found here: Compensation Parameters.

As part of the prequalification process, participants submit their individual variable and fixed electricity-related ancillary costs (SNK). For fixed ancillary costs, participants may only report costs that can be clearly attributed to the use of Section 13k volumes. Based on this information, the TSO determines the participant-specific maximum permissible compensation of electricity-related ancillary costs (SNK). Where SNK compensation is possible, the TSO specifies an annual minimum availability requirement (measured in hours per year). Meeting this minimum availability is a prerequisite for receiving compensation of fixed ancillary costs. Compliance is tracked cumulatively based on the daily availability reports submitted throughout the calendar year and is verified during the annual settlement process. Details can be found in the contractual documents (Remuneration Framework).

In the preceding month, participants submit a bid price for the following month. This bid price may not fall below the minimum price.

During the daily process, several steps are completed before 10:00 a.m.: Participants report their availability for the following day. Based on the forecast and tendered curtailed electricity volumes, the TSOs determine the cost-minimizing combination of bid price and participant-specific variable electricity-related ancillary costs and allocate the corresponding electricity volumes (quantity and timing). Procurement of the allocated electricity volume (“balancing energy procurement”) remains the responsibility of the participant. Whether the electricity is procured via the Day-Ahead Market, the Intraday Market, or bilateral power supply agreements (particularly PPAs) is irrelevant for participation in the mechanism.

On the delivery day, participants consume the allocated curtailed electricity volumes during the time windows specified by the TSO.

In the following month, remuneration and, where applicable, penalties are determined based on the submitted metering data. The remunerated quantity is the lower of the actual electricity consumption, and the allocated curtailed electricity volume. This volume is remunerated through a difference-price payment (reference price minus bid price), and compensation of eligible variable electricity-related ancillary costs. If actual consumption falls short of the allocated volume, remuneration is reduced accordingly and an additional penalty is applied. Consumption exceeding the allocated volume is neither remunerated nor penalized. Further details can be found in the contractual documents (Remuneration Framework).

After the end of the calendar year, compliance with the predefined minimum availability requirement is assessed. If the minimum availability requirement has been fulfilled, the participant becomes eligible for proportional compensation of fixed electricity-related ancillary costs (particularly grid fee demand charges). If the minimum availability requirement is not met, entitlement to this compensation is forfeited. Further details can be found in the contractual documents (Remuneration Framework).

Which data formats and communication channels are used?

The mechanism uses the ERRP data exchange processes defined under the SO GL. These processes are already widely used today for exchanging master data, planning data and unavailability notifications between generation facilities and TSOs.

The corresponding implementation guidelines are published on Netztransparenz.de: Netztransparenz > Electricity market design > SO Guideline > Data exchange > Implementation rules.

The process is characterized by:

• a cyclic data-exchange process running primarily from two days before delivery until delivery,
• the use of XML-based data formats (e.g. for time series),
• data exchange between the Facility Scheduling Coordinator (EIV) and the TSO via SFTP.
  
  

Where are data on curtailed electricity volumes and generation-ban time windows published?

Published information includes forecast curtailed electricity volumes, the aggregated volume allocated to participants and generation-ban periods for relief facilities in Segment 2. These data are published on Netztransparenz.de:

Use instead of Curtail

The data are additionally made available through an API interface: (API-Dokumentation und Hilfe | WebAPI-Portal)

Does the TSO supply the electricity volumes, or do I have to procure them myself?

No balancing-energy settlement is provided by the TSOs for the allocated curtailed electricity volumes.Participants are fully responsible for procuring the allocated electricity volumes and balancing group managment. Participants are free to choose how they procure the electricity, for example through power exchanges, OTC transactions or PPAs.

How does settlement work in principle, and which data are required?

Settlement is performed in accordance with the individual contracts under the framework agreement. The settlement process is based, among other things, on allocated curtailed electricity volumes and metered consumption values.

What happens if the allocated volume is not procured or consumed?

If a participant does not consume the allocated and confirmed curtailed electricity volume at the specified delivery time, penalties are applied in accordance with the framework agreement.

I operate an electricity storage facility and cannot fully charge the allocated volumes due to limited storage capacity. What happens in this case?

After the allocation of curtailed electricity volumes, participants confirm the volumes they can actually consume by updating their ERRP data no later than 12:00 noon on the previous day. These confirmed volumes form the basis for all subsequent process steps.

How is a “Use Instead of Curtail” activation remunerated?

By participating in the mechanism under Section 13k EnWG, participants do not receive free electricity from the TSO. Instead, they initially procure the allocated curtailed electricity volumes themselves, for example through the day-ahead market or alternative power supply contracts (e.g. PPAs). The resulting electricity procurement costs are initially borne by the participant.

Following successful activation and verification of actual electricity consumption within the periods specified by the TSO, participants receive a financial reimbursement and, where applicable, compensation of electricity-related ancillary costs in the following month. The basis for this remuneration is the curtailed electricity volume that was allocated on the previous day, confirmed by the participant and actually measured.

The reimbursement of electricity procurement costs is provided through a difference-price remuneration mechanism (“financial reimbursement”). This reimbursement is calculated as the difference between the applicable Day-Ahead price for the respective quarter-hour and the participant’s bid price (for competitive tenders from 1 October 2026 onwards), or the predefined 13k price during the pilot phase until 30 September 2026 inclusive. As a result, the effective electricity procurement costs for the allocated electricity volumes can be significantly reduced.

In addition, electricity-related ancillary costs may be partially compensated. These include variable components, grid charges, levies and surcharges, concession fees, electricity tax, fixed components, capacity-based grid tariffs and other fixed network charges. The individual level of compensation is communicated to each participant before the beginning of participation for the respective calendar year. In most cases, full compensation of electricity-related ancillary costs for the allocated electricity volumes is possible.

A simplified example for a hypothetical quarter-hour

• Allocated electricity volume: 10 MWh
• Day-Ahead price: 100 €/MWh
• Bid price: 30 €/MWh
• Electricity-related ancillary costs: 150 €/MWh

Step 1 – Initial costs (Electricity procurement costs and ancillary costs) borne by the participant

            10 MWh × (100 + 150) €/MWh = €2,500

Step 2 – Remuneration paid by the TSO in the following month by financial reimbursement and ancillary cost compensation:

            10 MWh × ((100 €/MWh − 30 €/MWh) + 150 €/MWh) = €2,200

Step 3 – Effective electricity costs

            €2,500 − €2,200 = €300

Further details regarding the remuneration framework can be found in the contractual documents.

Is the bid price subject to any limitations?

Yes. Participants determine a bid price for each relief facility or relief facility group one month in advance for each calendar month. This bid price must not fall below the minimum price established by the TSOs. The minimum price defines the lower limit for bid submissions and is set annually by the TSOs. It is currently in the range of 20 to 25 €/MWh.The currently applicable minimum price can be found under Compensation Parameters.

What happens if the Day-Ahead price is lower than the bid price?

In this case, the participant does not receive any financial reimbursement. However, the participant is not required to make any repayment either.

Why is the minimum price 20–25 €/MWh rather than 0 €/MWh? 

The legal framework requires remuneration to be limited to the redispatch costs that would otherwise arise (Section 13k (6) No. 4 EnWG). To ensure compliance with this requirement while simultaneously enabling participation by all eligible technology segments through the compensation of electricity-related ancillary costs, a minimum bid price is specified. A lower minimum price would reduce the possible compensation of electricity-related ancillary costs to such an extent that participation by Segment 1 facilities could become uneconomic or, in some cases, impossible.

Further details regarding the remuneration framework and the methodology for determining the minimum price can be found in the Implementation Concept .

During tender periods, increased renewable generation means the Day-Ahead price is always ≤ 0 €/MWh, so no remuneration will ever be paid.

No. An analysis conducted by the TSOs covering the tender periods between 1 October 2024 and 31 March 2026, together with the corresponding Day-Ahead prices, showed that the Day-Ahead price exceeded 20 €/MWh in more than 75% of quarter-hours. On average, the Day-Ahead price within tender periods during this timeframe was approximately 60 €/MWh.

Even in these situations (financial reimbursement = €0) electricity consumption can still be economically attractive because the Day-Ahead price is already below the participant’s individual bid price and electricity-related ancillary costs are additionally compensated (fully in almost all cases).

The minimum price is too high for hydrogen electrolysers.

The TSOs assume that the current minimum price of 20–25 €/MWh does not generally impair the economic viability of hydrogen electrolysers. This assumption is based on the fact that renewable electricity supply contracts required for RFNBO-compliant hydrogen production are currently typically concluded at higher price levels.

The TSOs further assume that hydrogen electrolysers aim to produce renewable hydrogen in accordance with the RFNBO requirements stemming from the delegated act under RED II Article 27, and the German implementation set out in the 37th BImSchV. As a consequence, electrolysers generally need to secure long-term fixed-price PPAs from renewable energy sources.Depending on technology and contractual structure, current indicative PPA price levels are typically in the range of 50–85 €/MWh (https://www.pv-magazine.com/2026/02/09/solar-wind-ppa-prices-continue-to-fall-in-europe/). Under current market conditions, the minimum price therefore remains significantly below this range, making supplementary electricity procurement through the Section 13k mechanism financially attractive. The TSOs also assume that the tender periods under Section 13k EnWG largely overlap with the production periods that hydrogen electrolysers would have operated in anyway under their wind-oriented PPAs. Accordingly, participation in the Section 13k mechanism is generally not expected to impose additional operational requirements on electrolysers. Furthermore, hydrogen produced during a Section 13k tender period may be classified as renewable hydrogen under the 37th BImSchV, which may further improve its economic attractiveness.

Are electricity-related ancillary costs such as grid charges compensated?

Yes. Compensated cost elements include grid charges, levies and surcharges, concession fees, electricity tax. Both variable and fixed cost components are eligible. However, compensation is capped to ensure that the “Use Instead of Curtail” mechanism does not become more expensive than the alternative redispatch costs. Each participant's individual compensation limit is communicated before the start of participation for the respective calendar year. In the vast majority of cases, full compensation of electricity-related ancillary costs for the allocated electricity volumes is possible.

Is compensation of fixed electricity-related ancillary costs possible for seasonally available facilities?

In principle, yes. Provided that sufficient “Use Instead of Curtail” activation hours occur during the available operating period, participants may receive full or partial compensation of the capacity-based component of network tariffs.

Is allocated curtailed electricity considered “green”?

When curtailed electricity volumes are allocated, participants do not receive guarantees of origin for renewable electricity pursuant to Section 42 EnWG. However, products manufactured using allocated curtailed electricity volumes may, in certain cases, be classified as renewable:

• Hydrogen produced using electricity allocated through the “Use Instead of Curtail” mechanism is considered renewable under Section 9 of the Ordinance on the Creditability of Electricity-Based Fuels (“Verordnung zur Anrechnung von strombasierten Kraftstoffen”).
• Pursuant to Section 16 of the Gas, Heat and Cooling Guarantees of Origin Register Ordinance (“Gas-Wärme-Kälte-Herkunftsnachweisregister-Verordnung”), guarantees of origin for heat produced using electricity allocated through the mechanism may be possible in the future. However, no definitive regulatory framework currently exists.

Information on guarantees of origin for renewable electricity can be found here (in German): Nachweissysteme für Energie und Klimaschutz | Umweltbundesamt .

At present, no guarantee-of-origin register for gas and heat is available from the German Environment Agency (status: June 2026).

What data are required for settlement?

The following data are used for settlement:

• Individual electricity-related ancillary costs collected during prequalification as part of the review of ancillary cost compensation.
• Operational process data, particularly the allocated and confirmed curtailed electricity volumes.
• Metering data: By signing the framework agreement, the participant authorises the TSO to use metering values transmitted pursuant to the German Metering Point Operation Act (Messstellenbetriebsgesetz) for settlement and verification purposes.

How do I register a facility for participation in the “Use Instead of Curtail” mechanism?

The facility must first be prequalified. Please also refer to:

Requirements for participation and Contractual Documents [LINK]

To initiate the process, a prequalification application must be submitted to the connecting TSO:

• 50Hertz: 13k@50hertz.com
• TenneT: 13k@tennet.eu

While the application is being reviewed by the TSO, the interfaces required for operational data exchange are established and tested.

Following successful prequalification, a framework agreement is concluded between the participant and the TSO. The facility is then eligible to participate in the allocation process for curtailed electricity volumes as of the first day of the following month.

What must the prequalification application contain?

The prequalification (PQ) application must contain the following components:

• Attachment 1: Participant Data Sheet
• Attachment 2: Relief Facility Data Sheet
• Attachment 3: Confirmation from the Connecting Network Operator (for facilities connected to the distribution network)
• Attachment 4: Application Form

The detailed requirements are specified in the Prequalification Conditions (PQ Conditions).

What consumption restrictions apply to existing facilities and new facilities that substitute fossil heat generation, as well as grid-connected electricity storage facilities?

Compliance with the statutory requirements and the determinations of the Federal Network Agency (BNetzA) regarding consumption restrictions is a key element of the prequalification process for existing and new facilities substituting fossil heat generation, and grid-connected electricity storage facilities.

For the PQ application, participants must demonstrate that electricity consumption occurs exclusively within the framework of Section 13k activations, except for the exemptions listed below. In the example below, the relevant demonstration period is October (the verification month depends on the participant's segment). After submission of the PQ application, the TSO has a processing period of one month (excluding any additional requests for evidence). During this review period, the participant is not subject to any consumption restrictions. Once participation in the allocation process begins, the general consumption restrictions apply (for example, Segment 1 facilities may not consume electricity outside Section 13k activations).

The facility may, in the month prior to registration pursuant to Section 13k (6) Sentence 2 No. 3 EnWG, and in each month preceding participation from the second delivery month onward, consume outside the Section 13k process only to an extent corresponding to a maximum of 2% full-load operation during the respective month.

Example

September:  No restriction on electricity consumption.

October: Verification month of the applicant (depending on the segment) to demonstrate additionality, i.e. consumption only within the Section 13k framework. Application submitted to the TSO at the end of October.

November:  Processing period for the PQ application by the connecting TSO, excluding any additional evidence requirements.

December: Participation in the allocation process from the beginning of December while complying with the applicable additionality requirements.

* Exceptions to the consumption ban:

The following exceptions apply:

• Monthly consumption up to 2% of full-load operation
• For existing and new facilities substituting fossil heat generation: consumption during start-up and shut-down ramps (these must be declared during prequalification)
• Provision of balancing energy services
• For grid-connected electricity storage facilities: consumption required for the provision of balancing reserves (e.g. achieving the required state of charge)