Open consultation

Open letter on technologies in the Capacity Market, 2026

Published 2 September 2026

Applies to England, Scotland and Wales

This open letter asks for views on whether there are any new or emerging generating technologies that could help maintain security of electricity supply and may need to be recognised in the Capacity Market.

We would welcome evidence from respondents on any such technologies, including how they operate, whether they are commercially viable, and how they could contribute at times of system stress.

Rule 2.4 of the Capacity Market Rules requires that, by 1 October each year, the Secretary of State consult interested parties to identify generating technologies that are capable of contributing to security of supply.

Where technologies are identified that are not already listed as a Generating Technology Class, the Secretary of State must amend the Capacity Market Rules as soon as reasonably practicable to make those technologies eligible to participate in the Capacity Market.

This open letter seeks views on whether such generating technologies exist.

In response to our consultation last year, stakeholders provided updates on emerging technologies that may be relevant to the Capacity Market. The department received 4 responses from stakeholders. We are grateful to respondents for taking the time to provide detailed responses and share their insights. A summary of last year’s government response and relevant developments is included below:

• Hydrogen to Power (H2P): the government has published a summary of responses received to the call for evidence on Hydrogen to Power and Interconnectors in May 2026, which sought evidence to inform how H2P plants should be categorised in the CM. The government will undertake further policy development and engage with CM delivery bodies to develop a proposed approach to H2P participating in the CM. We intend to outline our proposals as soon as possible
• Thermal Plasma Electrolysis (TPE): stakeholders highlighted new innovations in H2P through TPE as potentially enabling earlier and wider deployment of low-carbon H2P by improving hydrogen production at scale and at the point of use. Stakeholders suggested that TPE could be more efficient than other production methods, such as water electrolysis or steam methane reforming with carbon capture and storage. They also suggested it could support H2P deployment without some of the enabling infrastructure required by other hydrogen production pathways
• Consumer Led Flexibility (CLF): known as Demand Side Response in the Capacity Market Rules, CLF featured in multiple stakeholder responses. A significant volume of CLF already participates in the Capacity Market. Some respondents reiterated calls for separate technology classes and bespoke de-rating factors depending on technology types
• Flexible Compute Capacity (FCC): a new technology class of FCC was proposed. FCC was suggested as a form of CLF using existing cryptocurrency mining infrastructure which would be turned off at times of system stress. Stakeholders noted that, as FCC can be interrupted and restored frequently, with virtually no warm-up or cool-down time, and can sustain curtailment for hours or days, it should be designated under a new Generating Technology Class
• Offshore Hybrid Assets: as in previous years, stakeholders highlighted the potential for Offshore Hybrid Assets, including Multi-Purpose Interconnectors and Non-Standard Interconnectors combined with offshore wind

Government encourages respondents to provide evidence on any generating technologies that have emerged since the 2025 review which:

• are capable of contributing to security of supply
• are not already a Generating Technology Class
• may be eligible to participate in future Capacity Market auctions

How to respond

Please respond with details of any new generating technology and evidence of its contribution to security of supply to FutureElectricitySecurity@energysecurity.gov.uk by 11:59pm on 4 October 2026.

Some examples of the type of information that would support suggestions and aid our decision-making are provided below. Please note that this list is not exhaustive, and it is not necessary to provide all of the information below for us to consider your suggestion. However, the more information we receive, the more evidence we will have to assist in our decision-making process.

Please indicate at the point of submission if you are happy to receive follow-up communications and include your contact details in your response. Please also indicate whether you would like us to treat your response as confidential.

Types of information

Examples of the type of information include, but are not limited to:

• a brief description of the technology
• whether the technology already exists, including any examples of commercial deployment at scale
• whether there is evidence to show that the technology is commercially viable, for example a proven business model
• whether the technology is able to contribute to security of supply at periods of peak electricity demand, for example by generating electricity or reducing electricity demand
• any evidence relating to the reliability and availability of this technology at periods of peak electricity demand
• whether the technology is significantly different from existing Capacity Market Generating Technology Classes to warrant its own class
• a description of the fuel source or source of energy for the technology, including whether it is fuelled by a fossil fuel
• whether the output of this technology is fully controllable or dependent on an intermittent energy source
• whether there are any limitations on the length of time the technology can operate continuously at full capacity during peak periods, for example limitations on fuel, energy source, running hours, or typical duration limits

Next steps

We will publish the outcome of the review by 1 December 2026, in line with the requirements of Rule 2.4 of the Capacity Market Rules.

The government will continue to consider emerging technologies with the National Energy System Operator and delivery partners, including how best to assess their potential contribution to security of supply and any future participation in the Capacity Market.