Secondary control - Automatic Frequency Restoration Reserves (aFRR)

With the introduction of the balancing energy market, the aFRR market will be divided into two separate stages: balancing capacity and balancing energy tendering.

Within the scope of the balancing capacity tender market participants offer pre-qualified capacities, which they must also offer on the balancing energy market, in case the bid is accepted. In addition to the capacity offered, a bid for aFRR capacity is characterized by the capacity price. The bids submitted are ranked in ascending order according to this price (merit order list for capacity). The most favorable bids for APG are finally accepted - in accordance with the published award criteria and requirements - for the capacity reserve.

The second stage of the market is formed by intraday balancing energy tenders (balancing energy market). Here, providers can adjust the energy prices already submitted in the capacity tender or offer other pre-qualified capacities, independently of the balancing capacity tender. The submitted bids are again ranked in a merit order list according to their energy price.

The individual balancing energy bids are activated automatically - again in accordance with the published criteria - by the load frequency controller of APG, specifying a capacity setpoint with the aim of balancing the control area.

Tenders for aFRR in the APG control area

Below the most important information for potential providers of aFRR is presented. More precise and legally binding information can be found in the download section.

The tenders take place exclusively via the electronic tendering platform of APG. The documents required for participation in the tenders for aFRR can be found in the download section on the right-hand side.

See conditions for participation in the tenders for control energy.

Balancing capacity auction

Tendered volume

aFRR balancing capacity required in the APG control area currently amounts to +/-200 MW procured in daily capacity auctions. In exceptional circumstances, the required volume of aFRR can be changed by the control area manager.

Tendered products

aFRR is procured daily in six 4-hour blocks per day for positive and negative products:

Minimum and maximum bids

The minimum bid size per product is 1 MW. Bids in excess of the minimum bid can be submitted in full 1 MW increments and must not exceed the pre-qualified capacity. 

Capacity tender process

The required aFRR in Austria is tendered on a daily basis (calendar days, from Monday to Sunday). The most important deadlines for a tender are summarized in the following table: 

The following figure also shows the sequence for an entire delivery week:

Award procedure

At the end of the bidding period the offered aFRR capacity bids are ranked according to the following criteria:

1. lowest capacity price;
2. if the prices for capacity are the same, the award of the contract will be based on an algorithm for reproducible randomization

Market participants, whose bids are selected, receive the quoted aFRR capacity price, i.e. a "pay-as-bid" approach is used. The energy prices submitted in the capacity tender will be carried over to the energy tender and may be adjusted (downwards and upwards) until the end of the energy tender period.

Unsuccessful tender

In the event of an unsuccessful tender, e.g. in case not enough capacity is offered, the valid bids will be accepted and a “second call” will be opened for the shortfall. If there is still a shortfall after the second tender, a further invitation to tender will be opened in a "last call". In this case, APG calls on potential suppliers to offer available power via e-mail or, if possible, via telephone. In the event that the "last call" still does not suffice to cover the shortfall, APG has the right to oblige suppliers to provide the aFRR (obligation to supply). Detailed information regarding this procedure can be found in the Tendering Conditions for aFRR (German only).

Balancing Energy Auction

Tendered products

aFRR energy products are based on a validity period of 15 minutes:

Minimum and maximum bids

The minimum bid size per product is 1 MW. Bids in excess of the minimum bid can be submitted in full 1 MW increments and must not exceed the pre-qualified capacity.

Balancing Energy Tendering Process

The required aFRR balancing energy is put out to tender intraday (from Monday to Sunday). Bids can be submitted and adjusted from the successful completion of the capacity tender until 25 minutes before the delivery period of the respective product. The most important deadlines of the tender are summarised in the following table:

Award procedure

After the end of the bidding period, the offered aFRR energy bids are ranked according to the following criteria:

1. lowest energy price for positive aFRR or highest energy price for negative aFRR;
2. if the prices for energy are the same, the award of the contract will be based on an algorithm for reproducible randomization

Once a bid has been accepted, the provider is obliged to keep the accepted quantity available for activation at any time.

Backup procedure

If the process of energy tendering cannot be fully completed for technical reasons, all bids submitted up to that point will lose their validity. Backup energy prices are calculated for the creation of the merit order list.

The calculation of the backup energy prices for delivery day D are carried out for each provider and product based on the energy bids the provider submitted for the 14 delivery days before the Gate Closure Time of the capacity tender (D-1). The calculation steps for delivery day D are as follows:

• Sorting the bids of each provider per product
  • The energy bids for delivery days D-15 to D-2 are sorted according to the energy price (ascending for positive aFRR, descending for negative aFRR) and, in case of equal prices, ascending according to the size of the energy bid.
  • The capacity bids for delivery day D are sorted in ascending order by capacity price and, in the case of equality, by energy price (ascending for positive aFRR, descending for negative aFRR) and time stamp (ascending).
• Calculation of an average 1-MW-MOL
  • The average price for the first MW, the second MW, etc. is calculated based on the energy prices submitted.
  • This MOL must then be sorted again (ascending for positive aFRR, descending for negative aFRR).
• Calculation of the backup energy price MOL
  • The backup energy prices are calculated based on the 1-MW-MOL and the quantities of the bids submitted in the capacity tenders for the relevant delivery day D.
  • The backup energy price of a bid is calculated as the average value of the prices from the 1-MW-MOL corresponding to the quantities of the submitted balancing capacity bids.

Two special cases can occur regarding the calculation:

• The supplier has not submitted any valid energy prices for one or more products within the last 14 calendar days before the delivery date. As a substitute, the 1-MW-MOL for this provider is calculated as the average of the 1-MW-MOLs of all other providers.
• The quantity offered for a product in the respective capacity tender exceeds that of the last 14 delivery days and thus also the length of the 1-MW-MOL. In this case, the last backup energy price is applied for all subsequent MWs.