Energy Intensity Indicators: Highlights of Trends
The Energy Intensity Indicators Web site reports changes in energy intensity in the United States since 1985. The Web site discusses, and presents data for, energy intensity trends by sector and econcomy-wide. Energy intensity is measured by the quantity of energy required per unit output or activity, so that using less energy to produce a product reduces the intensity. Energy intensity trends are reported in two categories, total energy and delivered energy, for each of the four end-use sectors (transportation, industrial, residential buildings, and commercial buildings).
The energy intensity indicators control for structural changes in the economy that are not directly associated with energy efficiency improvement. This gives a truer measure of intensity change associated with energy efficiency improvement than the simple energy/GDP or a simple energy/activity ratio. Examples of structural changes include shifts from more energy-intensive industries, such as iron and steel, to industries that are less energy-intensive, such as computer manufacture, or shifts from passenger automobiles to SUVs.
Total energy consumption is the amount of fossil and renewable fuels consumed for the four end-use sectors, plus the electricity used by these end-use sectors (electricity sales). In addition, the losses associated with the production of electricity by the utility sector (i.e., losses that occur in the generation, transmission, and distribution) are also allocated to the end-use sectors. The sum of total energy for four end-use sectors (transportation, industrial, residential buildings, and commercial buildings) is equal to the sum of all primary energy consumed by the four sectors plus energy consumed by the electricity producing sector.
Delivered energy, on the other hand, is the amount of energy consumed at the point of sale (e.g., that enters the home, building, or establishment) without adjustment for energy loss in the generation, transmission, and distribution of energy. This is primary energy for the four end-use sectors plus electricity sales. Delivered energy is sometimes referred to as "site" energy.
The highlights of these energy intensity trends summarize the information found in the trend graphics and data.