Mapping supply chains for energy retrofit

This paper introduces social network analysis (SNA) to investigate retrofitting supply chains. It tests the approach by studying those undertaking whole-house retrofit of social housing in a case study city. Network visualisations and metrics including network density (overall connectedness), in-degree centrality (support needed to complete a task) and closeness centrality (speed of access to information) are used to compare how communication varies through different retrofit stages. The preliminary results indicate high density networks and strong ties amongst project leaders (the local authority and tier-one contractors), indicating the transfer of tacit, complex information. These project leaders retain a high closeness centrality throughout the retrofitting process, but there is uneven communication, with subcontractors experiencing infrequent communication and connection only to tier-one contractors. This does not necessarily hinder project success, but may indicate missed opportunities for shared learning. Further, as a quantitative mapping technique, SNA alone does not provide insight into the nature of the interactions taking place. The approach introduced here can be strengthened by incorporating analysis of the types of information exchanged and detailed qualitative insight into participants' experiences of communication throughout a single retrofitting project. PRACTICE RELEVANCE This paper develops an SNA approach to map the organisations involved in whole-house retrofitting in the social housing sector. The findings illustrate how patterns of communication change throughout the retrofitting process. The data show close collaboration between the project managers and tier-one contractors at the beginning (project definition) and end (commissioning and monitoring) of the retrofitting project. Tier-one contractors retain closeness to contractors during physical install, but the overall network is dispersed for this stage. For practitioners such as retrofitting project managers, the method can be used to understand how supply chains are coalescing under the PAS2035 standard, and indicate potential points where communication with and amongst contractors could be developed. The method could be powerfully combined with the evaluation of retrofitting outcomes to understand which types of supply chain structure are most effective in delivering successful retrofit.