Shifts in Product Mix Versus Energy Intensity as Determinants of Energy Consumption in the Manufacturing Sector

摘要

The energy intensity (EI) changes that occurred in manufacturing industries between 1975 and 1980 are examined, and future energy requirements are projected on the basis of various assumptions about such changes in the future. For the 1975 to 1980 period, the aggregate EI of non-electric energy use declined by about 21% (4.6% per year), with 75% of the change attributed to efficiency improvements and/or process changes and the remainder attributed to changes in the product mix of output. For electricity use the aggregate EI declined about 9% (1.8% per year) with over 90% of the change attributed to efficiency improvements and/or process changes. The effect of efficiency improvements and product mix changes on future manufacturing energy use was examined for eight cases - the combination of two EI scenarios with four alternative assumptions of industry-specific output growth rates. The two EI scenarios were: (1) 1980 EI values remain constant beyond 1980; and (2) trends in EI during the 1975 to 1980 period continue. The four economic growth cases considered were: (1) a continuation of the aggregate 1975 to 1980 growth rate of 3.96% with product mix held constant; (2) the historical trends in specific industries continued (product mix varies); (3) the Bureau of Industrial Economic projections, which also indicate product mix changes; and (4) the same as (3) except that petroleum refining, blast furnaces and steel mills, and primary aluminum decline at an annual rate of 3.5 to 4.0%. The growth rates in energy use to 1990 for these cases ranged from -1.31% to 3.96% per year for non-electric energy and from 1.62% to 3.96% per year for electricity. Preliminary results of the regional energy growth rates for two scenarios are also included. (ERA citation 09:000722)