In 1991, the manufacturing sector, on average, consumed more energy per value of shipments than in either 1988 or 1985, showing an increase in purchased energy intensity of four percent from 1988 to 1991. This increased energy requirement is a function of a myriad of internal and external factors. Among the numerous internal factors that could influence energy intensity are changes in manufacturers' internal mix of products produced during these years, and changes in the technologies and processes used to produce them.
Economic conditions represent one of the most influential external factors.
At one time, cost control had been cited as one of the most common business incentives for investing in projects to manage energy usage. Changes in Energy Intensity in the Manufacturing Sector, 1985-1991 presents statistics about changes in energy consumption per constant dollar of value of shipments. The 1991 MECS is the third survey conducted, with earlier surveys gathering information on 1985 and 1988 energy consumption patterns. The information in this report continues the data series on changes in energy intensity based on information collected by the two earlier surveys. Past manufacturing surveys did not collect information relating to the potential causes of changes in energy efficiency.