Dynamic Containment

Dynamic Containment (DC) is designed to operate post-fault, i.e. for deployment after a significant frequency deviation in order to meet our most immediate need for faster-acting frequency response.

Currently, the electricity system is experiencing lower inertia and larger, more numerous losses than ever before. Faster acting frequency response products are needed because system frequency is moving away from 50Hz more rapidly as a consequence of imbalances.

Over the next few years, the ESO aims to deliver a new suite of faster-acting frequency response services to support our operations as the electricity system is decarbonised and to ensure that these new services enable a level playing field for all technologies. Dynamic Containment is the first of our new end-state services that we will be releasing to mitigate this risk.



If you have any questions regarding Dynamic Containment, in the first instance please take a look at our FAQ document (the document will appear in your downloads folder).

Alternatively, please contact the team for any queries at: [email protected] 


New providers

If you are a new provider, please review the DC Participation Guidance Document in the 'How to participate' tab, in the 'Legal documents' section for details on how to join the service. If you have any questions, please contact the team at: [email protected]


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The two other services in Response Reform

Visit the Dynamic Moderation page

Visit the Dynamic Regulation page

Latest News

11/10/22 - On 6 October 2022 we held a technical webinar on the enhancements to the Ancillary Services Dispatch Platform. You can find the material below.

Watch the webinar 
Download the slides
Download the Q&A

31/3/22 - We have published the content from the webinar on performance monitoring held on 24 March. The webinar recording can be accessed here and the documents can be accessed via the guidance folder in the document library here.  

31/1/22 - Through direct engagement with providers following the launch of DC and via industry forums, providers highlighted aspects of the DC service design that created barriers to entry, one of which was GSP aggregation. We recognise that aggregation will play an important role in the future provision of ancillary services, and we propose to re-instate aggregation at GSP Group as soon as possible. We have published a document that explains the considerations we have taken into account to make this decision, what we’re planning to do to mitigate any operational risks, and the timetable for bringing aggregation at GSP Group back for DC. The document can be viewed here. If you would like to discuss this paper in more detail or have any feedback you can reach the team at [email protected]

2/10/21 - We launched the EBGL Article 18 Consultation for DC High which concluded on 19 July 2021. Ofgem have now approved our updates to the Service Terms and supporting documentation. You can view the new documentation in the 'how to participate' tab.


Soft launch of DC

Following the announcement in April on the delay to the delivery of Dynamic Containment (DC), the operational need for DC remained so we decided to take a similar delivery approach to the weekly auction trial, in learning by doing through a phased delivery. We started with a soft launch of DC in October, followed by the full delivery of the service in 2021. For more information, select here.


Dynamic Containment overview

Dynamic Containment (DC) is a fast-acting post-fault service to contain frequency within the statutory range of +/-0.5Hz in the event of a sudden demand or generation loss. The service delivers very quickly and proportionally to frequency but is only active when frequency moves outside of operational limits (+/- 0.2Hz).

What volumes are we going to procure?

Eventually, but not immediately, we expect to procure up to 1GW of this product in both directions. Our procurement will grow with the available market and our own system readiness, expecting ~500MW initially.

Is there a unit cap?

The unit cap is 100MW. We are eventually looking to have a diverse locational spread, so we are trying to encourage the right market behaviour for when locational mapping comes in.

Is there a volume cap?

Currently, the volume cap is expected to be around 500MW. We expect this to increase to around 1000MW in the future. This is to promote competition and increase liquidity in the frequency response market, reducing our overall balancing costs and increasing value for the consumer.

Can I stack DC with existing response and reserve?

DC can currently be stacked with the Balancing Mechanism (BM). We intend to allow stacking with new response and reserve products introduced in the future where possible. Generally, we would like to maximise the stacking opportunities, but it is not allowed for the same MW/MWh to be sold twice.

Is DC going to replace any response products?

Eventually yes. As we continue with the roll-out of our other new services, we will gradually procure less of the monthly-tendered FFR service, and our intention is to phase out the monthly tenders for FFR by Q4 2021/22. 

How will DC interact with other new products?

DC has been designed to meet our operational needs in coordination with two other frequency response products: Dynamic Moderation (DM) and Dynamic Regulation (DR).