Public tender for procurement of mFRR balancing capacity and/or balancing energy

The right to participate in the public tender is granted to all Balancing Service Providers that have a valid mFRR Balancing Service Agreement with the Transmission System Operator and have provided the appropriate financial security (deposit or bank guarantee).

For the purposes of the Rules for the Procurement of aFRR and mFRR Balancing Capacity and/or Balancing Energy, September 2026 (HOPS 9/2026), Balancing Service Providers are defined as Bidders.

Bidders submit bids for:

provision of mFRR balancing capacity,
balancing energy from contracted mFRR balancing capacity,
balancing energy from voluntary bids.

A Bidder whose mFRR balancing capacity bid has been selected for the relevant balancing service provision period is entitled to transfer all or part of its obligation to another Balancing Service Provider.

Procurement process overview:

Tendering for mFRR Balancing Capacity

mFRR product parameters:

Product mFRR R2
Min bal. capacity bid size	1 MW
Activation method	Manually DA (direct) and SA (schedule)
Bid divisibility (bal. capacity)	Divisible, in 1 MW increments
FAT	≤ 15 min
Direction	mFRR+ R2: (+) increase in delivery to the grid or decrease in withdrawal from the grid;
Direction	mFRR− R2: (−) decrease in delivery to the grid or increase in withdrawal from the grid
Maximum indivisible mFRR balancing capacity bid	20 MW
Maximum balancing energy bid	20 MW
Maximum indivisible balancing energy bid	20 MW
Minimum activation duration	30 min**
Maximum activation duration	2 h,*
Time between activations	mFRR+ R2: 8 h ,*
Time between activations	mFRR- R2: 4 h ,*
Energy Bid granularity	Portfolio, regulation group or regulation unit*

* For regulation units and groups with prequalified balancing capacity equal to or greater than 3 MW, the TSO may require balancing energy bids to be submitted at the individual regulation unit level.The method for submitting balancing energy bids for new regulation units is defined upon their inclusion in the portfolio of an individual Balancing Service Provider.If the method for submitting balancing energy bids for existing regulation units is changed at the request of the TSO, the Balancing Service Provider shall be notified at least 30 days in advance.Upon its own request and subject to the TSO’s prior approval, a Balancing Service Provider may submit bids at the regulation unit level.
** The balancing product parameters (minimum activation duration, maximum activation duration and time between two activations) apply to balancing energy bids covering two or more consecutive MTUs that relate to the same balancing product and the same resource object providing the service (regulation unit or group) and have the same bid quantity [MW].
*** With the consent of the Balancing Service Provider, a longer maximum activation duration and/or shorter time between two activations than specified above may be used, as set out in Annex 1 to the Agreement.

mFRR balancing capacity price limits

Price limits for the procurement of balancing capacity are defined as the unit price calculated in accordance with Article 11 and Annex 2 of PoUEES, i.e. as the regulated balancing capacity price for the provision of balancing services by the dominant Balancing Service Provider.

All prices are exclusive of VAT, expressed in EUR/MW/h and rounded to two decimal places.

Products

Direction

Price Limit

(EUR/MW/h)

mFRR+R2

6,64

mFRR−R2

−

9,50

Balancing energy price limits

The TSO may prescribe balancing energy price limits, in particular, but not exclusively, in cases where there are significant differences between the offered balancing energy prices and wholesale electricity market prices.

Balancing energy price limits for a Balancing Service Provider holding a dominant position in the balancing services market in the Republic of Croatia are determined in accordance with PoUEES.

All prices are exclusive of VAT, expressed in EUR/MWh and rounded to two decimal places.

Product	Direction	Price Limit (EUR/MWh)
mFRR+R2	+	not prescribed*
mFRR−R2	-	not prescribed*

* The TSO may update balancing energy price limits in accordance with these Rules for the Procurement of aFRR and mFRR Balancing Capacity and/or Balancing Energy and PoUEES, subject to prior publication on the HOPS website.

Tendering procedure and timeline for Balancing Capacity
The mFRR balancing capacity tender covers six four-hour time blocks:

00:00–04:00 (hours 1–4 of day D)
04:00–08:00 (hours 5–8 of day D)
08:00–12:00 (hours 9–12 of day D)
12:00–16:00 (hours 13–16 of day D)
16:00–20:00 (hours 17–20 of day D)
20:00–24:00 (hours 21–24 of day D)

Bid submission period:

GOT: 00:00 seven (7) days before the delivery day (00:00, D-7)
GCT: 10:00 on the day preceding the delivery day (10:00, D-1)
POT: 10:30 on the day preceding the delivery day (10:30, D-1)

mFRR balancing capacity bids are selected using a minimum-cost optimization method (MILP algorithm), as defined in Annex 5 of the Rules for the Procurement of aFRR and mFRR Balancing Capacity and/or Balancing Energy, September 2026 (HOPS 9/2026).

The total required amount of mFRR balancing capacity and/or balancing energy for the tender is published for each individual balancing product through the Balancing Platform as part of the tendering process.

Balancing energy bid submission process

Bidders whose balancing capacity bids have been selected in the tendering process are required to submit balancing energy bids in an amount equal to or greater than the contracted balancing capacity.

A Bidder whose balancing capacity bids has been accepted shall submit preliminary balancing energy bids no later than 14:30 on the day preceding the delivery day (D-1), GCT0.

Bidders whose balancing capacity bids have not been selected may submit voluntary balancing energy bids.

Balancing energy bid resolution: 1 MTU (15 minutes)
GOT: 7 days before the individual MTU (MTU – 7 days)
GCT0: 14:30 on the day preceding the delivery day (14:30, D-1)
GCT: 25 minutes before the start of the relevant MTU (MTU – 25 min).

Balancing capacity and balancing energy bids shall be submitted electronically via the HOPS IT system – Balancing Platform.

Results of public tenders for mFRR balancing capacity

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