In 2021 we launched the Stability Market Design innovation project to explore the design for the enduring stability market.  

This project has recently concluded and AFRY summarised their recommendations in an end of project webinar on 17 July 2023 (slides and recording available on the stability market design webpages).

As a result of this work, in our 2023 Markets Roadmap we set out the aim to procure stability services across several timescales: 

  • Long-term (Y-4)
  • Mid-term (Y-1) 
  • Short-term (D-1) 

We determined that the next step in launching our suite of Stability Markets is to initiate the mid-term (Y-1) market, starting with a request for information (RFI). 


Mid-term (Y-1) market request for information (RFI)

28 September 2023 – ESO have now completed the RFI review process and plan to launch the EOI phase in October 2023. 

In the interim, please refer to the RFI generic query log that has been created to summarise the generic queries that were received during the RFI process and ESO’s responses. 

Thank you for all of the feedback received, which has been used to finalise the details of the mid-term (Y-1) Market.

18 August 2023 – The ESO’s request for information (RFI) regarding the Stability mid-term (Y-1) Market has now closed.  

Thank you to the parties that provided responses, which will be used to help design and launch the market.  

If you have any questions, please get in touch using [email protected].

17 July 2023 – we ran an industry webinar signifying the conclusion of the Stability Market Design innovation project, followed by the launch of the mid-term (Y-1) Stability Market RFI. 

Download the RFI summary slides

Download the RFI

Download the RFI query log

Mid-term (Y-1) Round 1 2025/26

Mid-term (Y-1) Stability Market: Round 1, delivery year 2025/2026 

Launching the mid-term (Y-1) Stability Market is the first step in implementing the enduring Stability Market. 

On 18 August 2023 ESO concluded a request for information (RFI) which sought feedback from industry to help design the mid-term market. Using this market feedback ESO  continued to refine the design of the mid-term market, launching the first round of the mid-term (Y-1) Stability Market on 3 October 2023. On 31 May 2024 ESO received tender submissions, meaning the tender window has now closed for this first round. ESO will now assess these tender submissions in line with the published Contract Award Criteria before completing Contract Award.

Round 1 (2025/2026): process summary 

Step 1 – Expression of interest (EOI) and consultation window: October 2023 

This step initiates the first round of the mid-term (Y-1) Stability Market, seeking solutions that can help meet our Stability needs between 2025 and 2026. 

During this window, market participants are invited to express their interest in participating in the first round of the mid-term (Y-1) Stability Market. Market participants must formally express their interest to be invited to the invitation to tender (ITT) stage. 

ESO has published draft tender documentation which we welcome market feedback on as part of the consultation process. Please refer to the "documents and materials" section further down to access the EOI documentation. 

Key dates:

  • Consultation feedback deadline: 3 November 2023 (5pm) 
  • Expression of interest "early bird" deadline: 1 December 2023
  • Expression of interest "backstop" deadline: 26 January 2024

Please note as a result of consultation feedback, ESO may make amendments to the tender requirements and/or documents prior to the ITT stage. 

Step 2 – Launch invitation to tender (ITT): December 2023 (complete)

Market participants who express their interest in participating during the EOI window will be invited to the ITT stage. At this stage ESO will publish the ITT documentation. 

Step 3 – Invitation to tender (ITT) window: Complete

This is the period of time allocated for market participants to develop their technical and commercial submissions. Those participating must return their tender submissions to the ESO by the stipulated deadline to be considered for contract award. 

Step 4 – Contract award: planned  

Market participants whose tenders are successful will be notified by ESO and can begin work to meet their contractual requirements.


Documents and materials

EOI and Consultation Webinar