This study explores the relationships between metropolis energy consumption and environmental utility changes by a proposed Environmental Utility of Energy Consumption (EUEC) model. Based on the dynamic equilibrium of input-output economics theory, it considers three simulation scenarios: fixed-technology, technological-innovation, and green-building effect. It is applied to analyse Hong Kong in 1980-2007. Continual increase in energy consumption with rapid economic growth degraded environmental utility. First, energy consumption at fixed-technology was determined by economic outcome. In 1990, it reached a critical balanced state when energy consumption was 22 x 10(9) kWh. Before 1990 (x(1) <22 x 10(9) kWh), rise in energy consumption improved both economic development and environmental utility. After 1990 (x(1) > 22 x 10(9) kWh), expansion of energy consumption facilitated socio-economic development but suppressed environmental benefits. Second, technological-innovation strongly influenced energy demand and improved environmental benefits. The balanced state remained in 1999 when energy consumption reached 32.33 x 10(9) kWh. Technological-innovation dampened energy consumption by 12.99%, exceeding the fixed-technology condition. Finally, green buildings reduced energy consumption by an average of 17.5% in 1990-2007. They contributed significantly to energy saving, and buffered temperature fluctuations between external and internal environment. The case investigations verified the efficiency of the EUEC model, which can effectively evaluate the interplay of energy consumption and environmental quality. (C) 2012 Elsevier Ltd. All rights reserved.