Spatial-Neighbour Effects in the Installation of Solar Photovoltaic Technology in England and Wales

This article investigates spatial-neighbour effects in the deployment of small-scale solar photovoltaic (PV) systems, examining whether the installation rate in a given area is affected by the quantity of nearby solar PV systems. We study 1.4 million solar PV systems in England and Wales, analysing installations over the period 2010 – 2024. The results from 2010–2015 reveal that an additional solar PV system in a local authority is associated with an additional 0.128 installations 3 months later, suggesting a positive role of peer effects and observational learning. In contrast, from 2016–2024, spatial-neighbour effects are instead found to be negative, indicating saturation amongst the households likely to adopt solar PV. We further show that, by contrast, heat pumps do not exhibit any spatial-neighbour effects and that the collective buying scheme Solar Together did not appear to increase installations in the period 2015–2020.