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Dutch Ancillary Services

TenneT's main tasks are providing transport services, providing system services, providing a connection service and facilitating the energy market. To provide these system and transport services, TenneT uses ancillary services offered by the market.

On Ancillary Service

Directive 2009/72/EC defines "ancillary service" as: a service necessary for the operation of a transmission or distribution system;

These are services provided by users of the transmission or distribution system to the TSO or DSO for operating the transmission or distribution system.

TenneT uses these ancillary services for various purposes in accordance with its regulated tasks and obligations as a TSO. These ancillary services include:

  • Balancing reserves
  • Reactive power
  • Redispatch
  • Black start facility
  • Compensation of losses and sustainability of grid losses through Guarantees of Origin (GoOs)

International and national law prescribes the conditions under which an ancillary service is mandatory or voluntary and whether it should be paid or unpaid. In addition, users of transmission and distribution systems are legally obliged to comply with the requirements of the TSO and / or DSO for these services (including financial settlement of imbalance with the TSO).

TenneT procurers many of the necessary ancillary services regularly in the market. More information about the procurement process can be found on this page.

Balancing reserves

FCR (primary reserve power) is the power that is activated under the control of the primary regulation. The primary control is a locally designed automatic device, which ensures a constant ratio between frequency change and installation (power) change within a maximum of 30 seconds. The aim of FCR is to stabilise frequency disturbances in the entire (internationally) connected high-voltage grid, regardless of the cause and location of disruptions. Severe frequency disturbances can lead to automatic load shedding and in the worst case cause a blackout. ENTSO-e rules stipulate that the TSO must have a certain volume of FCR available. This volume is determined annually by ENTSO-e. It is because of this obligation that TenneT procures FCR.


The method of determination of the volumes is prescribed in European Laws. The main aspects can be found in:

  1. Commision Regulation (EU) 2017/1485 of 2 August 2017
     Article 153 FCR-Dimensioning (for Frequency Containment Reserve)
  2. SAFA (Synchronous Area Framework Agreement) annex: Policy on Load-Frequency and Reserves.

The FCR capacity needed for the synchronous area is set to the minimum of a reference incident and a probabilistic dimensioning analysis for FCR. The largest reference incident is determined on 3000 MW in positive direction and 3000 MW in negative direction.

The distribution of the total FCR volume among the individual TSO's is based on the net production and net consumption of their control area divided by the sum of net production and net consumption of the total synchronous area over a year. The outcome is expressed as a percentage, and called the frequency bias.

For 2019, the frequency bias of the Netherlands is 3.7%. This means that an outage of 1000 MW anywhere in the synchronous area, should result in a Dutch FCR contribution of 37 MW. Since reference incident is 3000 MW in total, TenneT has to have 111 MW (3.7% of 3000 MW) of FCR capacity available at any time in both upward and downward direction.

Year Volume (MW) Partial production in ENTSO-e RG-CE(%)
2013 114 3.80
2014 101 3.36
2015 96 3.20
2016 102 3.39
2017 107 3.56
2018 111 3.68
2019 111 3.70
2020 113 3,7701
2021 114 3,815
2022 116 3,867
2023 111 3,6848
2024 110 3,6745
Procurement process

TenneT organises daily auctions with 4 hourly blocks with other TSO's called "common auction". Imbedded within the algorithm of the common auction is the requirement for TSO's to guarantee 30% of the obligation for FCR is delivered within its control block.  This means 30% off the FCR Obligation is awarded to providers with connections in the Dutch control block. Non awarded bids will automatically become available on the merit order list of the common auction. To learn more about these auctions and the product FCR, read the following documents.

For maintaining the real-time power balance of the Netherlands, TenneT mainly uses bids for regulating power (aFRR) and reserve power (mFRRsa) offered by market participants to TenneT. The activation (dispatching) of FRR bids for balancing takes place in real-time operations. This regulating and reserve power is exlusively for correcting the real-time power imbalance.


The volume needed for FRR is a total of aFRR and mFRRda. First the total is determined and in a second step the minimum aFRR is determined. This is than deducted from the total (FRR) to get the needed mFRRda.

The volume of FRR is among other things based on historical imbalance values and on the size of a reference incident, or in other words the largest imbalance that can result from an instantaneous change of active power of a single power generation module, single demand facility or single HVDC interconnector, or from a tripping of an AC line within the LFC block.

The data used in deterministic, stochastic and probabilistic analyses. Article 157 sub 2 e and f, state that the dimensioned FRR volume is at least equal to the outcome of the deterministic approach (reference incident), or larger when the stochastic or probabilistic approach results in a larger volume.

The subdivision of the dimensioning of FRR into aFRR and mFRRda is done according to the Continental Europe Opertion Handbook, Policy 1. The policy describes a method to determine the minimum required volume of aFRR. TenneT may raise this minimum with an additional volume if required. This additional volume is amongst others based on the historical balancing quality.

Below you find a table with the determined dimensioning minimum of aFRR. The actual contracted volumes may differ to contract the best economic mix of reserves. 

Year aFRR (minimum) (MW)  
  UP Down
2013 300 300
2014 300 300
2015 300 300
2016 340 340
2017 340 340
2018 Q1-2 350 350
2018 Q3-4 320 320
2019 Q1-2 425 425
2019 Q3-4 385 385
2020 Q1-2 310 310
2020 Q3-4 310 310
2021 Q1-2 300 290
2021 Q3-4 290 290
2022 Q1-2 310 310
2022 Q3-4 323 324
2023 Q1-2 324 352
2023 Q3-4 324 362
2024 Q1-2 350 350


Procurement process

In order to ensure that sufficient bids of regulating power or aFRR is available at all times, TenneT enters into capacity contracts in which suppliers commit to making bids for a certain period. For this TenneT organises a weekly and as of the 1th of September 2020 a daily tender. To know more about these tenders and the product aFRR read the following documents.

TenneT uses the regulating and reserve bids for maintaining balance that have been made available by market participants. In addition, TenneT can use mFRRda, or incident reserves, for maintaining the balance in case of incidents and substantial long-lasting power deviations.


The dimensioning of mFRRda is part of the determination of FRR (total of aFRR and mFRRda). See dimensioning under aFRR.

Below you will find a table with determined volumes of mFRRda. The actual contracted volumes may differ to contract the best economic mix of reserves. 

Year mFRRda (MW)  
2013 350 n.a.
2014 350 n.a.
2015 350 n.a.
2016 350 200
2017 350 200
2018 Q1-2 650 672
2018 Q3-4 750 712
2019 Q1-2 720 652
2019 Q3-4 685 629
2020 M1-2 760 671
2020 M3-6* 994 715
2020 Q3-4 994 705
2021 Q1-2 1005 750
2021 Q3-4 1015 760
2022 Q1-2 995 835
2022 Q3-4 981 840
2023 Q1-2 980 940
2023 Q3-4 980 965
2024 Q1-2 954 726

 *Estimate FRR Q1-2 adjusted for 2020 due to changes in the largest-dimensioned failure.

Procurement process

Emergency power is contracted by TenneT at suppliers. The incident reserve supplier has the obligation, over the entire contract period, to be able to draw or supply the power agreed from the Dutch grid on call from TenneT. The emergency power is purchased weekly and as of the 1st of September 2020 daily. Learn more about the product mFRRda then read the following documents.

Pursuant to SO GL article 188 paragraph 3, TenneT is required to publish the outlook for reserve capacity before 30 November each year.  To ensure this, the outlook has been included in the dimensioning process which take place every 6 months. The outlook for 2022 is as follows:

LFC Block Date from Date to and including FRR forecast  
      Upward Downward
TenneT NL 1-1-2022 6-30-2022 1305 MW

1148 MW

TenneT NL 7-1-2022 12-31-2022 1320 MW 1330 MW
TenneT NL 1-1-2023 30-6-2023 1304 MW 1291 MW
TenneT NL 1-7-2023 31-12-2023 1304 MW 1310 MW
TenneT NL 1-1-2024 30-06-2024 1304MW 1076MW
TenneT NL 1-7-2024 31-12-2024 1304MW 1076MW

Note to the table: The numbers for 2024 Q3 and Q4 are forecasts and are therfore indicative and no rights can be derived from them.

Outlook 2030 for regulating FRR upward

The reserve capacity for FRR is based, among other things, on historical imbalance values and on the size of a largest reference incident event, or the largest imbalance that can occur in the Netherlands as a result of an instantaneous change in active power due to an outage of one power generation unit, one consumer unit or one HVDC interconnector, or an AC line within the LFC block.

The above data are used in deterministic, stochastic and probabilistic analysis. Article 157(2) e and f from the SO-GL (Regulation (EU) 2017/1485), states that the dimensioned FRR power is at least equal to the outcome of the deterministic analysis (reference outage situation) - or higher if the stochastic or probabilistic analysis has a higher outcome.

For now, the largest reference incident related to upward FRR is a 1304 MW large production unit. With the arrival of (multiple) off-shore wind farms with a connection to land via a 2 GW cable, the probability of failure of such a cables will increase. TenneT has analyzed this future situation. We conclude that, if the roll-out of the 2 GW connections (and wind farms to be connected to them) proceeds as planned, from 2030 onwards the largest reference incident that a deterministic determination of required reserve (FRR) should take into account will be 2 GW.

It is currently expected that such a (stepwise) increase for regulating FRR downward is not plausible although a gradual increase can be seen in the stochastic values of FRR over the years. For 2030 it is plausible the volume for downward can be up to 1800 MW.

Reactive power

Requesting a supplier of reactive power to deliver or absorb reactive power at the point of grid connection

The TSO must ensure adequate voltage control for the high-voltage grid. In order to so TenneT requests a supplier of reactive power to deliver or absorb reactive power at the point of grid connection at a level that differs from the standard exchange of 0 Mvar.

Procurement process

TenneT can enter into contracts with electricity producers that are connected to the EHV (380 kV / 220 kV) or the HV (150 kV / 110 kV) grid which put the reactive power range of each contracted production unit at TenneT's disposal. These contracts can apply for a specified period but also for a specified situation. The contracts are concluded following the outcome of a yearly tender.

To learn more about the product reactive power, read the following documents.


Redispatch (shifting in-feed and take-off of electricity from the grid) is one measure for solving expected transport problems (usually N-1 overload) in the high-voltage grid. By feeding in less power in one place and more (to the equivalent amount of) power in another place into in the grid, transports are influenced and transport problems can be solved.

For redispatch, TenneT can use the so-called "reserve power for other purposes" that are offered to TenneT.

Procurement process

Suppliers 'Reserve Power for Other Purposes' can submit bids to TenneT. These bids can, with the exception of the approval period, be adjusted to 3 Program Time Units (PTU's) before the PTU from start of delivery.

For more information about the product 'reserve power for other purposes' read the following documents.

TenneT performs redispatch when transport problems occur for which the solution is considered is shifting production. Because the location in the high-voltage grid where more or less energy needs to be fed-in is important, contact is initially sought with connected parties in the problem area. For this reason, unique bilateral contracts are concluded for redispatch with such parties. There is therefore no standard procedure for this.

Black start facility

One of the tasks of TenneT is to coordinate the restoration of electricity supply in the event of a black out. To be able to fulfill this task, TenneT requires facilities that can energise a grid and deliver power in a situation in which (a large part of) the actual grid voltage of national HV grid is equal to zero, in order to allow TenneT to restore the electricity supply. TenneT concludes a contract for the provision of a black start sevice only every so many years with contract period spanning multiple years because of the required investments.

A procedure to conclude a new agreement is announced well ahead of time.

Losses and sustainability

When electricity is transported a small share of this electricity is converted into heat. These so called grid losses are compensated by the TSO by procuring electricity.

TenneT distinguishes between the grid losses in the national AC-grid and the cable losses of the DC-cable to Norway (NorNed).

In addition TenneT procures Guarantees of Origin (GoO) corresponding to the volume of the grid losses.

Procurement process Grid losses (Extra) high voltage grid

The ancillary service requested  is the supply of electricty to compensate for total grid losses. This ancillary service is regarded as commodity to be  procured on an annual basis.

A tendering document is issued annually.

Procurement process Cable losses

Transmission of electricity on the NorNed cable also causes losses. These cable losses are taken into account using a fixed formula in the market coupling process. The resulting deficit or surplus is procured or sold separately. For these transactions a contract is concluded with a supplier on an annual basis. A document describing the requirements and specific way of working is drafted annually.

Procurement process Garantees of Origin (GoO)

In its capacity of TSO, TenneT procures the electricity that is necessary for a well-functioning system. This includes the compensation of grid losses and the cable losses Norned and the electricity consumption of converter stations. The source of this purchased electricity is not defined. However, to minimise the environmental impact of its own electricity consumption and to stimulate the production of renewable energy, TenneT procures Guarantees of Origin (GoO) based on an annual call for tender.