This study investigates the concept of “energy of scale“ in industrial energy systems, focusing on the reduction of specific energy consumption as production capacity increases. Using data from more than 25 000 industrial plants in Europe and the United States (U.S.), we develop fit functions for different industrial subsectors to validate the “energy of scale” effect. Our findings confirm that “energy of scale” exists in industrial energy systems and varies across subsectors. The effect is consistent between Europe and the U.S. We identify that energy-consuming units involved in value creation within production chains have the most significant influence on the scaling effect. This discovery has important implications for policy makers, facility managers, and energy researchers, providing new avenues for promoting energy efficiency and supporting the transition to cleaner energy sources.