Energy and material flows of megacities

TLDR

Megacities account for large shares of global energy and material flows—9 % of electricity, 10 % of gasoline, and 13 % of solid waste—underscoring their critical role in global environmental challenges. The study quantified energy and material flows for 27 megacities, showing that these flows follow city‑scaling laws and that electricity use correlates strongly with building floor area, linking micro‑ and macro‑level patterns.

Abstract

Significance Our quantification of energy and material flows for the world’s 27 megacities is a major undertaking, not previously achieved. The sheer magnitude of these flows (e.g., 9% of global electricity, 10% of gasoline; 13% of solid waste) shows the importance of megacities in addressing global environmental challenges. In aggregate the resource flows through megacities are consistent with scaling laws for cities. Statistical relations are established for electricity use, heating/industrial fuels, ground transportation, water consumption, waste generation, and steel production in terms of heating-degree days, urban form, economic activity, and population growth. Analysis at the microscale shows that electricity use is strongly correlated with building floor area, explaining the macroscale correlation between per capita electricity use and urbanized area per capita.