Results are presented of a study of fuel utilization and energy conservation for the six biggest energy consuming industrial groups: chemicals, primary metals, petroleum, paper, stone/clay/glass/concrete, and food. Total annual fuel usage in these industries in the early 1970s was 4569(+-500) x 10/sup 12/ kcal. Purchased electricity (valued at 2500 kcal per kWh) accounts for 17 to 18% of the energy use, coal for 18 to 19%, petroleum for 15 to 16%, natural gas for 35%, and other fuels for 13%. Unit operations accounting for energy use include direct heating (39%), compression (7 to 8%), distillation (6 to 7%), electrolysis (7 to 8%), evaporation (3 to 4%), drying (6%), cooking or digestion (4%), feedstock (10 to 11%), and other (15 to 16%). Approximately 800 x 10 to the 12th power kcal per year of energy is rejected in these industries at a temperature above 250 degrees C. Intense efforts at waste heat recovery should eventually allow use of most of this rather high level heat. In the short term, use of a variety of conservation approaches should reduce annual fuel use in the big six industrial groups by 774 x 10 to the 12th power kcal below the level withoutmore » conservation. (21 references) (GRA)« less