Understanding regional inequalities in electricity resources is crucial for achieving sustainable development goals, yet relevant spatiotemporal information remains limited. This study develops a systematic framework using multi-source nighttime light remote sensing data and geographical methods to reveal the inequality in electric power consumption (EPC) and its drivers along the Belt and Road (B&R) countries from 2000 to 2019. The findings show that EPC in the B&R region increased by 8.8 trillion kWh over the past 20 years, with a shift in its geographic center, highlighting mid-latitude cities as major growth hotspots. Differences in between-group and within-group inequality patterns across various spatial scales lead to a scale effect on EPC inequality. The overall EPC inequality of B&R decreased by 20% between 2000 and 2019, with inequality between countries being the main contributor, accounting for about 70%. However, at the national level, within-province inequality is the predominant source in most countries. The analysis identifies three key drivers, with affluence having a more significant positive impact on EPC inequality than population or electricity dependence. These findings are valuable for the sustainable development of urban energy and regional electricity resource planning amidst long-term geographical changes.