Guidance

Heat Network Technical Assurance Scheme (HNTAS)

Updated 30 July 2024

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This publication is available at https://www.gov.uk/government/publications/heat-networks-regulation-technical-standards/heat-network-technical-assurance-scheme-hntas

The Energy Act 2023 provides the powers for government to mandate heat network technical standards in Great Britain through regulations. We are introducing regulatory technical requirements and a Heat Network Technical Assurance Scheme (HNTAS) to help heat network operators demonstrate compliance with these requirements. HNTAS is due to launch in 2025 and aims to ensure that heat networks meet a minimum level of performance and reliability.

1. Overview of HNTAS

Since the end of 2022 DESNZ has been working with its Technical Author (Fairheat) to develop a technical standards Code. This sets out technical requirements (e.g. pipe insulation, water flow temperatures) which will be mandated in upcoming regulation. Many of these technical requirements build on the voluntary standards set out in CIBSE CP1 (2020). DESNZ and Fairheat have also been developing a scheme of assessment and certification to ensure heat network compliance with these technical requirements can be demonstrated. Together, these requirements and assurance processes form the Heat Network Technical Assurance Scheme (HNTAS).

Technical standards regulation will apply to heat networks from communal to city wide district systems, including both new build and existing legacy networks.

2. Objectives and principles

HNTAS is being designed with deliverability and proportionality as two of its leading principles. Specifically, we are keen to ensure that the introduction of HNTAS does not place undue burden or cost on heat network operators or heat network consumers.

HNTAS will enhance the transparency of heat network performance, and strengthen accountability for parties engaged in the planning, construction, management, and maintenance of heat networks. As a result, HNTAS has the potential to reduce carbon emissions by making heat networks more efficient, reduce capital and operational costs, and improve consumer experience. 

Scheme objectives and core principles

Vision

Enable low-emissions, reliable and affordable heat to be delivered to UK communities via heat networks.

Aim

Develop a heat network technical assurance scheme that ensures a minimum level of performance and reliability for heat networks in the UK.

Objectives

  • Reduce carbon emissions and cost of heat by making heat networks more efficient
  • Improve affordability by reducing capital and operational costs
  • Improve consumer experience with improved reliability and quality of heat supplied
  • Improve reputation and investor confidence in heat networks
  • Build evidence through better data collection and reporting on technical quality

Core principles

  • Outcomes orientated
  • Preventative
  • Proportionate
  • Deliverable
  • Adaptable
  • Enforceable

HNTAS will be a performance-based assurance scheme and applies to different identifiable elements (such as energy centre, district distribution network, communal distribution network) of a heat network. For each element, assessments against minimum standards are made in various lifecycle stages of a heat network. In the design and construction stages, assessments will be made to validate the claims that certain performance outcomes will be achieved. Upon commissioning, assessments will verify that performance outcomes have been achieved and maintained.

3. How compliance will be demonstrated

Under HNTAS, heat networks will be required to pass assessments to demonstrate that they have achieved the mandated minimum technical standards.

3.1 New networks

For new networks an assessment pass will be required at 3 key points in a heat network’s lifecycle:

  • before a network is allowed to start design
  • before starting construction
  • before starting operation

An assessment pass will also be required after 2 years of operation to ensure that performance levels continue to meet requirements.

3.2 Existing networks

For existing networks, assessments will be required after a set period to ensure performance levels meet requirements. The existing stock of communal and district heat networks will also have a significant transition period to get the right metering in place, to be able to prove performance. Final performance thresholds will be set at a more permissive level for existing networks and these networks will be given time to reach these.

3.3 After achieving HNTAS certification

For both new and existing networks, assessment passes will enable a network to be awarded a HNTAS certificate as evidence of compliance with HNTAS.

Once a network achieves HNTAS certification, the heat network operator will be required to regularly submit data to a HNTAS digital portal to show they continue to meet HNTAS key performance indicators.

4. Governance structure

As provided by the Energy Act 2023, Ofgem will be the regulator of heat networks. The Energy Act provides for Ofgem to award a licence to a technical standards Code Manager. It is expected that this Code Manager will maintain the Code documents which will include the:

1. Technical specification (what heat networks must comply with)
2. Assurance procedures (how compliance is demonstrated)
3. Assessor requirements (who can assess compliance)

The Code Manager may outsource the day-to-day operation of HNTAS to a service provider.

It is expected that registered assessors will be licensed by the Code Manager to carry out HNTAS assessments. We anticipate that organisations delivering certification activities would require accreditation.

5. Stakeholder engagement and consultation

Stakeholder engagement has been key in developing HNTAS. To date, 25 technical workshops have been held to gather ideas and expertise from manufacturers, housing associations, local authorities, consultancies, developers, contractors, energy service companies, trade associations, and professional bodies. 

The outputs of these workshops are being used to inform the Code documents, outlining the regulatory technical requirements of the scheme and how compliance can be demonstrated.  

The first draft of these documents, which includes the scheme’s technical assessment and certification requirements, will be completed shortly. We will be consulting on many of the HNTAS proposals and publishing the Code documents in some form in 2024. 

6. CIBSE CP1: Heat networks: Code of Practice for the UK

CP1 (2020), published by the Chartered Institution of Building Services Engineers (CIBSE), is the recognised Code of Practice for heat networks in the UK. It contains technical guidance and sets out voluntary minimum standards for UK heat networks. Having most recently been updated in 2020, CP1 will be the basis for the minimum regulatory standards used within HNTAS. It will also be further updated throughout 2024 to ensure continuing alignment with the HNTAS regulatory technical requirements.

CP1 (2020) is therefore not an exact representation of HNTAS standards, but it does give a very good starting point in that CP1 (2020) compliant networks will be very well prepared for forthcoming regulatory technical standards. Until recently it has only been free to CIBSE members, but a partnership between CIBSE and DESNZ has now removed the paywall to make CP1 (2020) free-to-all:

7. HNTAS pilot programme

We recognise the importance of testing the technical requirements and assurance processes on real networks to make sure they work in practice. Therefore we are undertaking an HNTAS pilot programme starting in the second half of 2024. Gemserv has been appointed the pilot scheme operator and will work closely with heat network operators and assessors participating in the pilots, developing the scheme in line with lessons learned. We are seeking heat network operators and assessors to take part. If you are interested in putting a heat network forward for the pilot or finding out more, please contact heatnetworks@energysecurity.gov.uk.

8. Next steps

  • Autumn 2024 to Spring 2025 - HNTAS pilot programme
  • Winter 2024 – first draft of Code documents completed
  • Winter 2024 - technical standards consultation
  • Within 2025 - HNTAS launches

9. News update and reference materials

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