Home Knowledge Base FAQs



What is an explicit auction?

In an explicit auction, only transmission capacity is being auctioned. Any customer who wins capacity in an explicit auction will receive Transmission Rights to use the interconnector for the duration of the Product Period.

The customer will still need to purchase or produce the electrical energy that they want to transport from one market to another over the interconnector.

BritNed only offers explicit auctions and these are held for Long Term, Day Ahead and Intraday timeframes.

Does BritNed hold implicit auctions?

BritNed does not offer any capacity into implicit auctions.

In an implicit auction, transmission capacity and electrical energy are auctioned together. Implicit auctions are facilitated by power exchanges and are typically only used for Day Ahead and Intraday timeframes.

The Day Ahead market coupling mechanism that operates in the Internal Energy Market is an example of an implicit auction.

What is the high-level process for an auction?

All of our auctions follow a similar process:

• Auction specification published

• Auction runs

• Provision results published

• Final results published

• Notification of Transmission Rights

For Long Term and Day Ahead auctions, this process will run in eCAT. For Intraday auctions, this process will run in Kingdom.

What types of auctions does BritNed hold?

Annual, Quarterly, Monthly, Weekend and Day Ahead are held on the eCAT system.

Intraday auctions are held on the Kingdom system.

In the event of a planned outage, if I purchase monthly capacity with a planned outage in the month, does the auction include capacity for the days where there is a planned outage or does it exclude them?

Any auction that is held and covers a period that includes a planned outage, the planned outage dates will be removed from the capacity. E.g. For a monthly auction, it is a 31 day month with a 3 day planned outage, the auction product will have 28 days of capacity.

What time zone are auctions based on?

Central European Time (CET) and Central European Summer Time (CEST) are used as the time zones for all Long Term, Day Ahead and Intraday auctions.

• At 02:00 CET on last Sunday in March, time will be adjusted forward 1 hour to 03:00 CEST.

• At 03:00 CEST on last Sunday in October, time be adjusted backward 1 hour to 02:00 CET.

What is Delivery (D) day?

All processes and timings are depending on the Delivery day. For instance, if Delivery day is Wednesday, D-2 is Monday and D+2 is Friday.

Where can I find the latest auction schedule?

The latest auction schedules for Long Term, Day Ahead and Intraday auctions can be found on the Auction Schedules page.

Long Term

What is a Long Term capacity auction?

Long Term capacity auctions refer to all products that have a delivery period of longer than one day.

For more information, see the Capacity Auctions.

For details on when the auctions are taking place, see Auction Schedules.

What is Use It Or Sell It (UIOSI)?

Capacity purchased in Long Term auctions and not nominated for physical delivery will automatically be placed in the relevant Day Ahead auction for sale with any revenues being returned to the customer.

When are Explicit Long Term capacity auctions held?

Auctions are held throughout the year for each of the Long Term products offered on the JAO eCAT platform. You can find the latest auction calendar here.

Day Ahead

What is a Day Ahead capacity auction?

Day Ahead capacity auctions refer to a product that has 24, 1 hourly delivery periods for a given delivery day. The auction results will show 24 separate prices, one for each hour of the delivery day. The auction takes place the day before the delivery day, for example the Day Ahead auction that takes place on 21 March is for delivery on 22 March.

For more information, see the Capacity Auctions.

For details on when the auctions are taking place, see Auction Schedules.

What is Use It Or Lose It (UIOLI)?

Capacity purchased in a Day Ahead auction and not nominated will be lost without any financial compensation.


What is an Intraday capacity auction?

Intraday capacity auctions refer to a product that has hourly delivery period with the auction happening a few hours before delivery.

For more information, see the Capacity Auctions.

For details on when the auctions are taking place, see Auction Schedules.

When are Intraday capacity auctions held?

There are currently four intraday auctions each day, you can find an overview of the schedule here.

What is an Intraday Trading Limit (ITL)?

A limitation placed on BritNed by NGESO to reduce intraday capacity.

What is a Restriction on Market Parties (RMP)?

A limitation placed on BritNed by TenneT to reduce intraday capacity.

Why is an ITL or RMP placed upon BritNed?

An ITL or RMP can be put upon BritNed’s flow by the GB and NL System Operators, they can ask us to restrict our Intraday Auction capacity.

Where can I find ITL’s communicated?

ITL’s are communicated on ETP.

Where can I find RMP’s communicated?

An RMP will be listed in the operational messages on the TenneT website. The message will have the title 'Transport Restriction'.

The RMP value will also be reflected on ETP under 'Intraday Transfer Limits'.

How can I calculate the offered capacity in the Intraday Auction?

Participants will be able to calculate the offered intraday capacity, by taking the DC link value from ETP (link), and then adding or subtracting from BritNed’s netted nomination flow , which is available from the Aggregated Netted Nomination screen in RNP, and as per the formula and example below:

In the flow Direction:

DC link value – Netted Nomination = Offered Capacity.

Opposite flow direction:

DC link value + Netted Nomination = Offered Capacity.


DC link value = 1016

Netted nomination = 600 NL - GB

NL to GB Offered capacity

1016 - 600 = 416MW offered capacity

GB to NL Offered capacity

1016 + 600= 1616MW offered capacity

Find out more about Empire - our exciting new auction and nomination platform

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