The global economy is becoming less energy intensive, using fewer fossil fuels to power productivity and economic growth, according to new data from the U.S. Department of Energy. Global energy intensity — a measure of energy consumption per unit of gross domestic product (GDP) — has decreased nearly one-third since 1990, the agency said. The U.S., for example, burned 5,900 British thermal units per dollar of GDP in 2015, compared to 6,600 BTUs in 2010.