Unveiling energy equity in rural heating decarbonisation: a behaviour-resolved techno-economic optimisation framework

The transition to electrified heating and distributed renewable energy is pivotal for residential decarbonisation but relies heavily on planning models that optimise for aggregate community loads. This “community-first” approach implicitly assumes that individual demand patterns smooth out constructively, masking the liquidity risks imposed on vulnerable households. In this study, a comprehensive framework is proposed that integrates a high-resolution, bottom-up stochastic demand model (N = 200 individual households, established upon a baseline case in Chengdu, China) with multi-objective techno-economic Optimisation to explicitly quantify these distributional impacts. The analysis reveals a fundamental divergence between system efficiency and distributive justice. First, the mechanism of a “capital trap” is demonstrated: as the targeted decarbonisation rate increases from 60% to near 100%, the physical necessity for substantial infrastructure oversizing (e.g., PV and battery capacities reaching 2000 kW and 3992 kWh) causes the mean CAPEX burden ratio across all households to escalate sharply from approximately 20% to over 100%, driving to prohibitive levels. Second, a cross-climate analysis exposes a geographic inequity. Due to the seasonal mismatch between solar availability and heating load, the median infrastructure cost in severe cold climates is nearly double that of mild regions ($0.83 million versus $0.44 million). This absolute capital inflation forces the CAPEX burden to 49%–77% for middle-income households, potentially leading to a liquidity crisis and engendering a class of “energy working poor.” Third, whilst internal cost-allocation mechanisms can mitigate relative unfairness, they fail to address absolute insolvency. Finally, a paradox is identified in future scenarios where technological cost reductions incentivize infrastructure oversizing, which inadvertently aggravates the absolute capital entry barrier for the relatively poor households. Consequently, this study supports a bottom-up, equity-centric approach in designing renewable energy systems.