In December 1998, the Office of Energy Efficiency and Renewable Energy of the Department of Energy published "United States Industrial Motor Systems Market Opportunities Assessment." The report is based on statistical sampling methods applied to the results of on-site visits to a cross-section of domestic manufacturing plants during 1997. This comprehensive, inch-thick report suggests that plant maintenance and management professionals are not taking advantage of many energy-savings measures available to them. It identified the barriers that prevent managers at industrial facilities from capturing more than a small percentage of the potential benefits of motor system efficiency. It also serves as a benchmark against which plant professionals can measure their own procedures.
This report represents a prodigious effort that has not been duplicated in the last 20 years. The Market Assessment was carried out by Xenergy Inc. under a subcontract with Oak Ridge National Laboratory (Lockheed Martin Energy Systems). The objectives of the project were to:
- Develop a detailed profile of the current stock of motor-driven equipment in U.S. industrial facilities.
- Characterize and estimate the magnitude of opportunities to improve the energy efficiency of industrial motor systems.
- Develop a profile of current motor system purchase and maintenance practices.
- Develop and implement a procedure to update the detailed motor profile on a regular basis using readily available market information.
- Develop methods to estimate the energy savings and market effects attributable to the Motor Challenge Program.
The basis for the project was on-site studies of 265 industrial facilities in 20 areas nationwide in SIC codes 20 through 39 (see sidebar). The number of sites studied constitutes a carefully designed probability-based sample of the manufacturing sector. The database covers almost 29,300 motors and their driven equipment as well as instantaneous load measurements on nearly 2,000 motor systems.
The report identifies two categories of motor system energy efficiency measures that a plant can take. The first are motor efficiency upgrades that improve the energy efficiency of the motor driving a particular machine or group of machines. The second are system efficiency measures that improve the efficiency of a machine or group of machines as a whole by reducing the load on the motor, matching component size and load requirements, using speed controls, better maintenance, or other engineering strategies. The report notes that only 9.1 percent of the motors in use in manufacturing facilities meet the federal efficiency standards that took effect in late 1997. It also predicts that it will take 15 to 20 years to replace 80 percent of the motors in the 1 to 200 horsepower range based on the current pattern of motor purchase and rewind.While the Motor Challenge Program can document over a dozen major projects that yielded system-wide savings of 33 percent or more, this report notes that there are barriers to capturing the financial and operating benefits of motor system energy improvements.
- Low priority of energy efficiency among capital investment and operating objectives because, in manufacturing as a whole, motor system energy costs constitute less than one percent of total operating costs.
- General lack of awareness among facility managers of strategies, costs, requirements and benefits associated with achieving motor system efficiencies.
- Generally low level of staffing for the facility maintenance function.
- There are conflicting incentives for suppliers regarding the promotion of efficient equipment and practices, an example being the greater incentive to sell additional equipment to customers with increasing loads rather than advising customers how to control load growth through better maintenance and production planning.
The findings from the study
The key findings that came out of the study might be surprising.
- Industrial motor systems consume over 679 billion kWh, or 23 percent of all electricity sold in the United States.
- Motor energy use could be reduced by 11 to 18 percent if facilities managers undertook every possible cost-effective application of mature proven efficiency technologies and practices.
- Improvements to pumping systems, fans and air compressors represent up to 62 percent of the potential savings.
- In the manufacturing sector, using adjustable speed drives reduced energy consumption by anywhere from 3 to 6 times the energy savings from improving air compressor systems.
- For specific facilities and systems, potential savings far exceed the industry average.
- Motor system energy use and energy savings are highly concentrated by industry and size of plant (1.5 percent of plants--3,583--account for nearly half of the energy use and potential savings in the manufacturing sector).
- The financial impact of motor-related energy savings is substantial on industries that use significant amounts of motor energy because these plants typically operate on thin margins and operating cost reductions have a greater impact on profitability.
- The magnitude and pattern of motor energy use and potential savings varies greatly among industries.
- Except in the largest plants, the level of knowledge and implementation of systematic approaches to motor system energy efficiency is low.
- Overcoming the barriers to adoption of energy efficient motor systems purchase and management practices will be difficult.
This study has some clear implications for the design of the Motor Challenge Program itself. The report suggests that:
- Resources should be focused on the industries in which the highest levels of savings is possible (chemicals, primary metals, paper and allied products, water supply and wastewater, and mining).
- Resources should be focused on teaching manufacturers, designers, distributors and purchasers of pumps, fans and compressors to specify and maintain optimized systems.
- End-users need educational opportunities and tools to learn and apply knowledge of motor efficiency.
The report highlights information that plant mangers can use for benchmarking purposes. For instance, only 9.1 percent of motors currently in use meet standards of the Energy Policy Act of 1992. Of those that meet the standards, most are in the 101-200 horsepower range.
The study found that only 9 percent of the motors that were observed were equipped with adjustable speed drives. Of those with an adjustable speed drive, over 90 percent were 20 horsepower or smaller. Of these, most adjustable speed drives were intended for process control reasons, not energy conservation.
The study revealed that 44 percent of the motors observed in action were operating at part load and below the efficient operating point. This implies that there may be many entire pump, fan and fluid handling systems operating below optimal efficiency.
Over 90 percent of motor purchase decisions are made at the plant level but only 19 percent of respondents reported being aware of so-called "premium efficiency" motors. Only four percent understand the efficiency ratings associated with these motor designations while 38 percent reported being somewhat aware of the relationships. Only 22 percent reported purchasing an efficient motor in the previous twelve months.
Regarding the way that replacement motors are specified, 29 percent report they use the size of the failed motor as the sole criteria, a practice that leads to persistent oversized, inefficient operations. Only 11 percent report having any written specifications for motor purchases and only two-thirds of these have specifications covering efficiency.
Only 12 percent of respondents report considering lower energy operating cost as justification for a rewind versus replace decision. Most others consider only minimizing capital costs. Of those that rewind, very few report providing specifications to rewind contractors. The report claims that improper rewinding of motors can reduce its efficiency from one to 2 percent.
The study asked whether plants implemented specific system-level modifications to improve energy efficiency in pumps, fans and compressors over the previous two-year period. Except for fixing air leaks, none of the measures were mentioned by more than eight percent of the respondents.
The report itself has three sections and four appendices. Section one is an inventory of U.S. industrial motor systems. It focuses on the distribution of motor systems and energy by industry, horsepower, application, efficiency, hours of use and part load.
Section two discusses energy savings opportunities with estimates of potential savings by type of measure, industry, application and motor size. Section three focuses on motor purchase and maintenance practices.
Appendix A contains profiles of five motor system energy-using sectors. Appendix B gives details of the inventory and potential savings as a function of SIC code. Appendix C explains the methodology of the study and Appendix D contains a description of the forecasting model the study used along with forecast results through the year 2002.
For more information on the Motor Challenge Program, including MotorMaster +3.0 software, visit http://www.motor.doe.gov/mcssoft.htm
For a copy of the U.S. Industrial Electric Motor Systems Market Opportunities Assessment, call Motor Challenge at 800 862 2086.