Guiding Industrial Energy Management by Measuring Savings from Energy-Efficient Practices

Efforts to measure industrial energy-efficiency savings have been made difficult by changing weather and production between pre- and post-retrofit periods, both of which are frequently major drivers of plant energy use. This paper demonstrates a methodology for measuring energy-efficiency savings using multivariable change-point models and readily available utility, weather and production data. These models account for changing weather and production between pre- and post-retrofit periods and allow for disaggregation of savings into constituent components. Disaggregating savings provides resolution for understanding the efficacy of individual projects when several projects are implemented together and to uncover the synergies weather and production have on energy efficiency projects. This method is demonstrated with two case studies. These case studies are of actual energy assessments and demonstrate the importance of adjusting for weather and production between the pre- and post-retrofit periods and how plant-wide savings can be disaggregated to evaluate the effectiveness of individual retrofits. In addition, the method identifies the time-dependence of savings and how insight into unexpected results can be interpreted from these models.