The Department for Energy Security and Net Zero (DESNZ) has published the draft Heat Network Technical Assurance Scheme (HNTAS) Technical Specifications and Assessment Procedures for Existing Heat Networks.
This latest release represents another significant milestone in the development of the HNTAS framework and follows the publication of similar draft documents for New Build Heat Networks last month.
What’s been published
HNTAS is a performance-based assurance scheme, which contains impartial assessment and independent certification, to ensure that heat network performance outcomes are achieved and maintained.
To facilitate this, Technical Specifications and Assessment Procedures set out the requirements which need to be fulfilled as part of HNTAS, and the assessment activities undertaken to provide assurance that these are met.
What is a Technical Specification
A Technical Specification sets out the requirements which need to be met at a given Phase of a heat network’s development, for each Element within a heat network.
These requirements consist of:
• The Technical Requirements to be met
• The Performance Monitoring Requirements to be met
• The Key Failures to be avoided at each stage
• The Evidence Requirements to be provided
What is in an Assessment Procedures document
The Assessment Procedures set out the assessment activities to be undertaken to provide assurance that the standards within a Technical Specification have been met.
For each requirement set out in a Technical Specification, the document sets out:
• The minimum level of assessment
• The activities which form the Assessment Procedure for that specific requirement
Their roles within the scheme
Within HNTAS, an Existing Heat Network is separated into constituent Elements:
• Energy Centre
• District Distribution Network
• Substation
• Communal Distribution Network
• Consumer Connection
The compliance pathway for an Existing Heat Network is split into different Milestones, which represent distinct sets of requirements that networks will have to demonstrate within a defined timeline.
The milestones include:
- Milestone 2 – Minimum performance and reliability thresholds, including metering and monitoring requirements
- Milestone 3A – Performance Improvement Plans
- Milestone 3B – Metering and monitoring requirements for networks not required to meet these at Milestone 2
- Milestone 4 – Requirements for achieving HNTAS Certification
Within the HNTAS Code documentation structure, 24 new documents have been released containing the draft Technical Specifications and Assessment Procedures for Existing Heat Networks.
Why this matters
These documents aim to give the sector clear visibility on expected requirements for Existing Heat Networks, allowing the market to prepare for these incoming requirements.
Much of the content reflects existing and established good practice across the sector, now brought together into a clear and structured framework.
Who this is for
The draft documents are aimed at heat network operators, contractors and consultants responsible for managing the operation and maintenance of Existing Heat Networks.
Acknowledging industry collaboration
Overall industry engagement for HNTAS has involved collaboration with 123 organisations and 222 individuals to date.
This includes 15 organisations and over 30 individuals involved in the Pilot Programme for Existing networks. Learnings from both the New Build and Existing Pilot Programmes have influenced these draft Code documents, and are also expected to be fed into future revisions of the Existing and New Build Code documents.
