How High Concentrations of Financially Enabled Households and Behavior Shape Solar Home Systems Expansion in Underserved Communities in Nigeria: Insights from a Stylised Spatial Agent-Based Expansion Model

Government efforts to reduce the energy access deficit in Nigeria have largely focused on improving the affordability of Solar Home Systems (SHSs), implicitly assuming that this will expand the concentrations of financially enabled households and drive rapid, widespread SHS installations in underserved communities. While recent literature has increasingly recognised affordability perceptions and choice behaviour as drivers of SHSs adoption, no study has examined how high spatial concentrations of financially enabled households interact with these factors to shape expansion. This study, therefore, asks how high spatial concentrations of financially enabled households interact with affordability perceptions and choice behaviour to shape SHSs expansion. The Consumat, a stylised agent-based model, which simulates heuristic decision-making across product options, is extended using qualitative insights triangulated with quantitative evidence from three neighbouring underserved communities. These data capture residential differentiation and contextual affordability perceptions shaped by price information and lived experiences of electricity access. Simulation results from the extended stylised model show that the high-concentration scenario produces predictable declines in adoption as affordability thresholds increase, whereas low-concentration scenarios generate erratic adoption responses among high-income consumats. Crucially, when SHSs prices fall below the income midpoint, the high-concentration scenario generates a spillover effect that elevates adoption among low-income consumats. These findings reveal that the high-concentration scenario reinforces social signals, through which price sensitivity produces predictable and directional effects on adoption, including spillover effects. The model offers policymakers a tool for designing spatially targeted pricing interventions that accelerate SHSs expansion in high-concentration and underserved scenarios.