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Leading service provider for Transmission System Operators (TSOs) in the European electricity market.

Through our single trading platform we auction cross-border transmission capacity rights. We also provide accounting (clearing and settlement), contracting, reporting, project support and IT services.

 

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Auctions

On behalf of TSOs, we organize long and short-term auctions of transmission capacity rights.

We offer the following products: yearly, seasonal, quarterly, monthly, weekly, daily and intraday.

Auction results Auction calendar
OPS
  • 500+
    Registered market participants
  • 26k+
    Auctions held annually
  • 100%
    Auction tool availability
  • 80+
    Employees
  • 50
    TSOs serviced

Latest market messages

Publication Tool configuration update | API | 19.11.2026

by JAO

Dear Market Participants,

To ensure the continued stability and performance of the Publication Tool service for all users, JAO will introduce a maximum limit of 100,000 records for the Take parameter on applicable API endpoints.

What is changing?

Effective from 19.11.2026, API requests using the Take parameter will be limited as follows:

  • New Maximum Value : 100,000

Requests specifying a value greater than 100,000 will be rejected and an error response will be returned.

Why are we introducing this limit?

Our analysis of production traffic has identified several requests retrieving exceptionally large result sets, in some cases requesting hundreds of thousands or millions of records in a single call. Such requests significantly increase database workload and response times and may impact service performance for all Publication Tool users.

This change is therefore being introduced to:

  • Improve overall API responsiveness.
  • Reduce the risk of timeouts and service degradation.
  • Ensure fair usage of shared platform resources.
  • Increase the reliability of data retrieval during peak publication periods.

Recommended data collection approach

For regular automated data collection, JAO recommends:

  • Using FromUtc and ToUtc parameters to retrieve only the required period.
  • Splitting large business-day requests into smaller time windows (for example hourly intervals).
  • Applying available filters to reduce the volume of returned data.
  • Sending requests sequentially rather than in parallel.
  • Storing retrieved data locally instead of repeatedly requesting the same information.

Further guidance

Detailed recommendations and best practices for efficient API consumption are available in the JAO Publication Tool API Usage and Best Practice Guide

We appreciate your cooperation as we continue to improve the reliability and performance of the JAO Publication Tool services.

Kind regards,

JAO Support Team

Update: eCat Platform Currently Unavailable

by JAO

Please be advised that the  eCAT platform is now available again,


eCat Platform Currently Unavailable

by JAO

Please be advised that the ecat platform is still inaccessible following the scheduled maintenance

Further updates will be provided as they become available.

2026 Auction Calendar update

by JAO

We would like to inform you that, as per TSOs request, the 2026 Auction Calendar has been updated on the corridor NLL-BE<>GB.

For more details please refer to the Auction Calendar on our webpage http://www.jao.eu/auctions#/calendar/table to find its latest version.

Capacity Curtailment on the NSL-GB-N2 border for delivery period 06-11-2026

by JAO

1. TSO(s)*:

NGNSL_IC

2. Identification of affected Long Term Transmission Rights:

NSL-GB-N2

3. Triggering event:

Curtailment to ensure operation remains within Operational Security Limits

4. Affected volume in MW / hour for each concerned period:

06-11-2026 16:00 - 17:00 98 MW

06-11-2026 17:00 - 18:00 98 MW

06-11-2026 18:00 - 19:00 98 MW

06-11-2026 19:00 - 20:00 98 MW

06-11-2026 20:00 - 21:00 98 MW

06-11-2026 21:00 - 22:00 98 MW

06-11-2026 22:00 - 23:00 98 MW

5. Amount of LTTR remaining after curtailment:

06-11-2026 16:00 - 17:00 0 MW

06-11-2026 17:00 - 18:00 0 MW

06-11-2026 18:00 - 19:00 0 MW

06-11-2026 19:00 - 20:00 0 MW

06-11-2026 20:00 - 21:00 0 MW

06-11-2026 21:00 - 22:00 0 MW

06-11-2026 22:00 - 23:00 0 MW

6. Information on exact operational security limit(s) that are expected to be violated in the absence of curtailment*:

  Thermal Limits

7. Why alternative measures are not sufficient to avoid the expected violation of operational security limit(s)*?

Capacity limitation due to NTC restrictions

Delay in the publication of Publication Tool data

by JAO

Please be informed that there is a delay in the publication of data on PUTO for BD 05/11

The relevant data will be published as soon as possible.

We apologise for any inconvenience this may cause and appreciate your understanding

Capacity Curtailment on the GR-IT border for delivery period 06-11-2026

by JAO

1. TSO(s)*:

TERNA

2. Identification of affected Long Term Transmission Rights:

GR-IT

3. Triggering event:

Curtailment to ensure operation remains within Operational Security Limits

4. Affected volume in MW / hour for each concerned period:

06-11-2026 00:00 - 01:00 499 MW

06-11-2026 01:00 - 02:00 499 MW

06-11-2026 02:00 - 03:00 499 MW

06-11-2026 03:00 - 04:00 499 MW

06-11-2026 04:00 - 05:00 499 MW

06-11-2026 05:00 - 06:00 499 MW

06-11-2026 06:00 - 07:00 499 MW

06-11-2026 07:00 - 08:00 499 MW

06-11-2026 08:00 - 09:00 499 MW

06-11-2026 09:00 - 10:00 499 MW

06-11-2026 10:00 - 11:00 499 MW

06-11-2026 11:00 - 12:00 499 MW

06-11-2026 12:00 - 13:00 499 MW

06-11-2026 13:00 - 14:00 499 MW

06-11-2026 14:00 - 15:00 499 MW

06-11-2026 15:00 - 16:00 499 MW

06-11-2026 16:00 - 17:00 499 MW

06-11-2026 17:00 - 18:00 499 MW

06-11-2026 18:00 - 19:00 499 MW

06-11-2026 19:00 - 20:00 499 MW

06-11-2026 20:00 - 21:00 499 MW

06-11-2026 21:00 - 22:00 499 MW

06-11-2026 22:00 - 23:00 499 MW

06-11-2026 23:00 - 24:00 499 MW

5. Amount of LTTR remaining after curtailment:

06-11-2026 00:00 - 01:00 0 MW

06-11-2026 01:00 - 02:00 0 MW

06-11-2026 02:00 - 03:00 0 MW

06-11-2026 03:00 - 04:00 0 MW

06-11-2026 04:00 - 05:00 0 MW

06-11-2026 05:00 - 06:00 0 MW

06-11-2026 06:00 - 07:00 0 MW

06-11-2026 07:00 - 08:00 0 MW

06-11-2026 08:00 - 09:00 0 MW

06-11-2026 09:00 - 10:00 0 MW

06-11-2026 10:00 - 11:00 0 MW

06-11-2026 11:00 - 12:00 0 MW

06-11-2026 12:00 - 13:00 0 MW

06-11-2026 13:00 - 14:00 0 MW

06-11-2026 14:00 - 15:00 0 MW

06-11-2026 15:00 - 16:00 0 MW

06-11-2026 16:00 - 17:00 0 MW

06-11-2026 17:00 - 18:00 0 MW

06-11-2026 18:00 - 19:00 0 MW

06-11-2026 19:00 - 20:00 0 MW

06-11-2026 20:00 - 21:00 0 MW

06-11-2026 21:00 - 22:00 0 MW

06-11-2026 22:00 - 23:00 0 MW

06-11-2026 23:00 - 24:00 0 MW

6. Information on exact operational security limit(s) that are expected to be violated in the absence of curtailment:
HVDC cable ARACTHOS – GALATINA

7. Why alternative measures are not sufficient to avoid the expected violation of operational security limit(s)?
Not Applicable

Our certifications

JAO has successfully implemented internationally recognized management systems and is now officially certified for ISO/IEC 27001:2022 – the global standard for Information Security Management Systems, and for ISO 9001 – the international standard for Quality Management Systems. 

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About us

We started as a shared auction platform for transmission capacity across Central Western Europe in 2008. Over time, we became the operator of the Single Allocation Platform and therefore the leading trading platform for European Transmission System Operators.

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Frequently asked questions

Check out the common questions and our answers on how to use the auction platform.

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