A New Methodology for Calculating The Energy Performance of Manufacturing Facilities

ABSTRACT

Total energy comparison (TEC), classic energy intensity (CEI), and linear regression models (LRM) are the three most common approaches used to track the energy performance of manufacturing facilities. TEC simply compares the total energy consumption from utility bills. TEC is rarely used because it does not consider the variation of any factors that may affect energy consumption. One step better, CEI considers the variation of production rates by using the ratio of annual total energy consumption over annual total production. However, CEI fundamentally assumes that energy consumption is zero if the production rate is zero. This is almost never true and can cause significant errors. Using linear regression models, LRM considers the impact of multiple variables and, therefore, most accurately tracks energy performance. Unfortunately, because of the lack of either required data or technical expertise, some facilities cannot create valid linear regression models. For these cases, CEI is the only option. The goal of this article is to develop a new methodology, modified energy intensity (MEI), which is more accurate than CEI, but requires much less data and is easier to implement than LRM. Using the underlying principle of LRM, this article first outlines the mathematical derivation of the equations for MEI, then explains them from an engineering perspective. Finally, the implementation of MEI is discussed.

Keywords::

• energy efficiency
• manufacturing facility
• energy performance tracking
• linear regression model
• classic energy intensity
• modified energy intensity
• energy management

Acknowledgments

This work was supported by the Advanced Manufacturing Office of the U.S. Department of Energy.

Additional information

Notes on contributors

Wei Guo

ABOUT THE AUTHORS

Wei Guo, PhD., PE, CEM, is an R&D Associate Staff member in the Energy Efficiency Research and Analysis Group at Oak Ridge National Laboratory (ORNL). His research area is mainly focused on improving energy and material efficiency for general and special manufacturing equipment and processes. He has been working on smart manufacturing and data analytics, combined heat and power, industrial water management, and recycling and waste management projects for in recent years. Dr. Wei Guo is a Senior Member of Association of Energy Engineers. He is an AEE Certified Energy Manager and registered Professional Engineer. He received his PhD in Mechanical Engineering from the University of Arkansas, Fayetteville. Dr. Wei Guo may be contacted at [email protected].

Thomas Wenning

Thomas Wenning, PE, CEM, is the corresponding author for this article. He is a program manager for industrial energy efficiency at the U.S. Department of Energy's Oak Ridge National Laboratory (ORNL) and a Joint-Faculty Assistant Professor in the Department of Industrial and Systems Engineering at the University of Tennessee. Mr. Wenning has led the creation and delivery of several of the Department of Energy's technical assistance and deployment efforts. Chief among them, he has led the implementation and delivery of the DOE's Better Buildings, Better Plants Program, which works with over 200 major companies to help them improve their energy management programs and reduce their company-wide energy intensity. In addition, he is leading the DOE's effort to modernize their energy system software tool suite and associated training resources. Lastly, Mr. Wenning has also led and represented the DOE in numerous international industrial energy efficiency workshops, trainings, and assessments. Mr. Wenning is a registered Professional Engineer, an AEE Certified Energy Manager, a Certified Practitioner in Energy Management Systems, an SEP-Performance Verifier, and a DOE Qualified Specialist in the areas of steam, pumps, and fans. Mr. Thomas Wenning may be contacted at [email protected].

Sachin Nimbalkar

Sachin Nimbalkar, PhD, is a group leader at the Oak Ridge National Laboratory. Dr. Nimbalkar provides technical support to DOE's Better Buildings, Better Plants Program Partners.

Kiran Thirumaran

Kiran Thirumaran is a research associate at the Oak Ridge National Laboratory.

Kristina Armstrong

Kristina Armstrong is a post-master's researcher at the Oak Ridge National Laboratory.

Eli Levine

Eli Levine, JD, CEM, is a Program Manager for the Better Plants program in the Advanced Manufacturing Office at the U.S. Department of Energy.