Delivering a decarbonisation feasibility study and archetype-based retrofit assessments to test the viability of district heat network connection against individual heat pumps.
Project Overview
- Client: Somewhere Co-operative Housing Association
- Sector: Co-operative Housing / Social Housing
- Location: Bedminster, Bristol
- Services Provided: Retrofit Assessment, Decarbonisation Feasibility Study
- Scale: 14-property portfolio; 4 sample properties; 2 assessed in detail
- Target: Baseline EPC D; assess viability of Bristol Heat Network (Vattenfall) connection vs. individual ASHPs – funded via the Bristol City Leap Community Energy Fund
The Challenge
Somewhere Co-operative Housing Association (SCHA) wanted to understand the best decarbonisation route for their 14-property portfolio – and specifically, whether connecting to the emerging Bristol Heat Network, operated by Vattenfall, made more sense than installing individual air source heat pumps property by property. Answering that question properly meant more than a desktop comparison: it needed real assessment data, and a way of accounting for the fact that the heat network’s own carbon intensity is expected to improve significantly over the next few years as its fuel mix evolves.
The Solution
Archetyping, Modelling & Heat Network Feasibility
SCHA identified four Victorian terraces on St Philip Street as their representative sample for the study; within the project’s budget, we assessed two of these in detail – enough to establish a reliable baseline while keeping the study cost-effective for a co-operative operating on tight margins. We modelled both today’s grid factors and Vattenfall’s projected future fuel mix, since the network itself is expected to decarbonise significantly over the next few years, and defined a “Heat Network Ready” fabric specification prioritising insulation ahead of any connection decision. We also compared the cost and practicality of a shared community network against individual heat pumps – finding a shared connection came in at roughly a third of the cost per dwelling.
The Outcome
The data fed directly into the wider feasibility study, and the conclusion was clear: individual connection to the primary heat network wasn’t viable for these properties on any economically sound basis. Instead, the recommended path is a community-owned secondary heat network – SCHA aggregating demand with neighbouring properties into a single, collectively-owned connection to the main network. This isn’t just the more affordable route; it shifts residents from being individual utility customers to collective stakeholders with real ownership over their own thermal grid. Alongside this, the study set out a fabric-first roadmap toward a significantly improved EPC rating.
