The Department for Energy Security and Net Zero (DESNZ) has published the draft new build technical specifications and assessment procedures for its heat network assurance scheme.
The overview gives the first detailed insight into what compliance with the Heat Network Technical Assurance Scheme (HNTAS) will require. It contains KPIs and an outline of the technical and procedural obligations across the new build ‘assurance pathway’. It will apply to communal and city-wide district systems. Existing heat network documents have yet to be published.
KPIs include acceptable heat losses for the secondary heat network – a key measure for performance. The limit is 100W per dwelling on average, the same as the voluntary standards set out in CIBSE CP1 (2020).
Co-technical author and FairHeat principal engineer Tom Burton said the metrics were very achievable for networks that follow good practice and the peer approval process. ‘Those who have been working to CP1 will sail through these KPIs,’ he said.
Assessments against minimum standards will be made in the various stages of the life-cycle for six heat network elements, including the energy centre and distribution systems.
At design and construction stages, assessments will be made to validate claims that certain performance outcomes will be achieved. A network passing an assessment will be awarded an HNTAS certificate as evidence of compliance with the scheme.
Once a network achieves this certification, the heat network operator will be required to regularly submit data to HNTAS to show it continues to meet key performance indicators.
A public consultation, and more documents covering life-cycle stages, are expected to follow soon.
How HNTAS aims to put consumers first
By Tom Burton, co-technical author, HNTAS
HNTAS is heavily consumer focused. Its aim is to provide assurance that minimum levels of performance and reliability are being achieved, meaning lower costs,
improved comfort and fewer outages.
The newly published documents reflect extensive work and industry engagement to establish KPIs that identify the root causes of poor heat network outcomes, such as heat loss and instability in temperature and pressure. This allows visibility of problems that have previously been difficult to diagnose because of a lack of data.
HNTAS is a preventative assessment regime, where decisions made at each stage of the design/construction/commissioning process will be assessed.
Assessment will be a cost for developers, but there is strong evidence that this will result in overall savings in the development and operation of heat networks.
One of HNTAS’ aims is to improve the reputation of heat networks, allowing them to grow at the pace needed by government to meet its target of distributing 20% of heat through heat networks by 2050. View documents at bit.ly/4oLKLdy
