Determining energy savings from reductions in the energy intensity of manufacturing processes is increasingly popular. However, promoting energy efficiency through productivity improvements is not a widely accepted practice. As such, accepted methods used to calculate energy savings from productivity improvements are not prevalent.

In this paper, a conceptual and mathematical framework for determining energy savings from productivity improvement projects is presented. Several existing energy efficiency programs that either promote productivity improvements or claim energy savings from productivity improvements are described, along with the rational of these programs. Several existing savings calculation methods are briefly described. Then, the relationship between production and manufacturing energy use is reviewed on a plant-wide and equipment level. Four categories are proposed to categorize manufacturing equipment based on their relationship between production and energy use. Next, the importance of establishing both a baseline and production-adjusted baseline of energy use for each equipment category is discussed. Finally, two proposed mathematical approaches for calculating energy savings will be presented with examples as applied to several “Lean Manufacturing” improvements.