The quantity of energy (direct and/or indirect) that has been consumed in the manufacture of a product measured at the production point or in the provision of a service measured at the point at which the service is provided.
The energy intensity of a country’s economy refers to the energy and fuel consumed per unit of GDP produced in the country. Energy intensities change over time.
This measure is typically calculated on a national basis. It shows that the economic efficiency of energy usage has improved or remained comparable throughout the world over the last two decades.
Energy intensities tend to trend downwards, due to:

• Normal structural changes, i.e. the transfer of resources from energy heavy to energy light sectors

• Autonomous energy efficiency improvements, meaning progress that happens by itself, so to say, not because of political signals

• Policy measures to make car manufacturers produce more fuel efficient cars, households insulate their houses better, etc.

In 1980, 15,000 British thermal units (Btu) of energy were needed for every dollar of GDP produced in the United States, compared with just under 9,000 Btu in 2006, a 40 percent improvement. Most countries, including China, have experienced similar gains in efficiency due to advances in technology and more sophisticated business management practices