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Duffryn heat network is the largest domestic district heating network in Wales -supplying 1,000 homes, a school, and sheltered accommodation across the Duffryn Estate. Since 2014, we have acted as lead consultant, designer, and client engineer across three successive phases of decarbonisation and network improvement, transforming the scheme from oil-fired heat supply to a best-practice biomass district heating network with a fully replaced buried infrastructure. The scheme comprises a 2.5 MW Polytechnik wood chip boiler, 50,000 litres of thermal storage, three 1.5 MW gas backup boilers, and 3.5 km of pre-insulated steel and polymer pipework connecting 29 substations and 1,000 properties.
Over ten years of continuous engagement, we have taken the Duffryn heat network from aging oil-fired boilers through to a fully decarbonised, optimised, and renewed district heating system -delivering the largest biomass district heating scheme in Wales, a complete upgrade of heating systems across all 1,000 properties, and a full replacement of 50-year-old buried pipework completed in 2024. Our support has also secured £3.7m of HNES grant funding, and the network is now operating at significantly reduced flow and return temperatures, minimising heat losses and extending the lifetime of plant and infrastructure.
Scope
In 2014, we were appointed by Newport City Homes to undertake a feasibility assessment for the decarbonisation of the Duffryn heat network, identifying a 2.5 MW wood chip boiler with thermal storage and gas backup as the optimum solution. We delivered detailed design, tendering, commissioning management, and RHI accreditation support, with the biomass energy centre -delivered in partnership with British Gas under the ECO funding scheme -completed in 2016. In 2017, we were reappointed to design, specify, procure, and supervise a full heating system upgrade across all 1,000 properties, profiling 45 distinct property types to complete heat demand modelling, HIU and radiator sizing, and detailed M&E design -with all works completed in 2018 and network operating temperatures reduced from 80°C/68°C to 75°C/50°C flow/return. In 2022, we were appointed to undertake a condition assessment of the existing buried network -concluding it had reached the end of its serviceable life -before delivering full detailed design and specification of a replacement hybrid steel and polymer pipe network, supporting NCH to secure £3.7m of HNES grant funding, procuring delivery contractor, and acting as Client Engineer through to completion in May 2024.
Services
Sustainable Energy Ltd has acted as lead consultant, designer and client engineer for all developments and improvements to the Duffryn heat network over the last 10 years.
Design for the biomass boiler energy centre, supporting the tendering process and construction of the project through to handover, design of new dwelling heating systems, HIUs and metering through to commissioning management, heat network design, funding support, procurement, supervision and client engineer. Sustainable Energy continues to support NCH with network efficiency and optimisation including controls modifications.
Feasibility Assessment, Detailed Design & Specification, Hydraulic Modelling, HIU & Radiator Sizing, Procurement Support, ECO & HNES Grant Funding Support, RHI Accreditation, Client Engineer, Construction & Commissioning Management, Network Optimisation.
Solution
A phased programme of investment transformed the Duffryn network from an aging oil-fired system into a best-practice biomass district heating scheme -ensures the estate will benefit from reliable, renewable heat supply for a further 50+ years.
The energy centre comprises a 2,500 kW wood chip boiler with 240 m³ fuel store, which allows it to receive a daily articulated lorry volume of sustainable, local, woodchip. Thermal storage of 50,000 litres allows the biomass boiler to deliver heat to the district heat network efficiently and consistently. Three 1,500 kW gas boilers provide energy for backup and peak heat demand conditions.
The system includes an electrostatic filter, ensuring emissions are minimised to the lowest feasible levels. Full integration of the biomass and gas boilers is aided by a comprehensive control and monitoring system.
The heat network comprises 3.5 km of pre-insulated steel and polymer buried pipework which connects 29 substations which in turn supply Danfoss SAV direct heat interface units and heating systems that operate at temperatures of 70/40C. Metering and billing is provided by Switch 2 using the G6 pre-payment system.