With multiple resources and savings tactics, think of this as a pop quiz you get paid to take, with no wrong answers.
Nearly two-thirds of the electricity consumed by industrial users in the United States is related to motor-driven equipment - think of all the pumps, fans, air compressors, and other mechanical devices that are used in nearly every type of industrial facility. The DOE’s Industrial Technologies Program estimates that motor-related systems operated by the nation’s most energy-intensive industries consume about 290 billion kWh/yr. Moreover, the DOE estimates that industrial motor energy use could be reduced by between 11% and 18% if industrial facilities fully embraced all available efficiency measures. Doing so would provide $3 to $5 billion in annual electricity savings while producing 15 to 26 fewer million metric tons of annual carbon emissions - a win-win for the economy and the environment.
The potential for significant motor-related energy savings is certainly not limited to the industrial sector. Believe it or not, there are an estimated one billion electric motors in operation in the U.S. Together, they consume more than half of the nation’s electricity. In the typical commercial building, for example, one can find plenty of opportunities for motor efficiency improvements. Pump, fan, and other motor-related loads represent a major portion of a commercial building’s energy consumption. The motors used in HVAC and refrigeration systems alone can account for 30% or more of a commercial building’s energy use.
DIALING UP THE MOTOR SAVINGSToday’s managers have plenty of reasons to redouble their efforts at making their operations more efficient. A weak economy underscores the need to prune operating expenses. The unrelenting ascent of energy prices makes the “utilities” line-item an excellent place to start. And with ENERGY STAR® benchmarking, LEED® certification, and carbon reduction initiatives all gaining traction in the marketplace, more and more managers are looking beyond the “low-hanging fruit” to meet their new and aggressive savings goals. Fortunately, managers interested in improving motor system efficiency have plenty of resources to help them do so, including but not limited to the following:
- The National Electrical Manufacturers Association (NEMA) offers the Premium Motors program, which provides a specification and brand for manufacturers to label highly energy-efficient motors.
- The Consortium for Energy Efficiency (CEE) manages and coordinates Motor Decisions Matter, a national public awareness campaign that promotes system efficiency by encouraging industrial and commercial customers to evaluate their motor repair and replacement options and to develop a motor management program before motors fail. CEE promotes motors that meet the NEMA Premium Motors criteria, and its website features an abundance of useful resources and links.
- The Energy Efficiency and Renewable Energy (EERE) division of the DOE has developed the BestPractices Motor Systems Initiative, which offers publications, software tools, and training specific to motor systems.
- And speaking of the federal government, the Federal Energy Management Program (FEMP), which helps federal purchasers make more energy-efficient procurement decisions, also supports the NEMA Premium label and offers additional tips for managers interested in maximizing the efficiency of their motor systems.
MAKING MOTOR EFFICIENCY AFFORDABLESpecifying NEMA Premium motors can be particularly cost-effective when annual operation exceeds 2,000 hrs, where utility rates are high, when motor repair costs are a significant fraction of the price of a replacement motor, or where utility incentives are available. Of course, the longer the operating hours or the higher the utility rate, the more likely it is that even a small improvement in motor operating efficiency would produce significant enough energy savings to generate an attractive return on the required incremental investment.
DOE’s BestPractices program offers the example of a 75-hp motor running at 75% load for 8,000 hrs/yr at an efficiency of 91%. Over a 10-yr operating period, the purchase price of this motor might represent as little as 2% of the total motor installation and operating costs - the other 98% of the cost is related to energy and maintenance. That reality underscores the importance of not only specifying the right motor for an application, but also devoting resources over its lifetime to motor testing and maintenance. And remember that a NEMA Premium motor may cost as little as 10% to 15% more than a motor that just meets federally mandated guidelines for efficiency, so it’s often the superior choice even in situations where utility incentives are unavailable.
Speaking of incentives, more and more utilities are focusing on the impact that motor-related systems have on their grids. Many use motor-related programs as an entry point to discussions of larger system savings. For these and other reasons, the number of programs providing funding to improve the energy per-formance of motor systems continues to grow.
The CEE recently observed that “programs are transitioning away from standalone motor rebate programs to a more comprehensive mix of program approaches such as adjustable-speed drives and motor management services.” It also cites an increased number of offered measures; in some cases, they are bundled under one umbrella program. The CEE reports that many of its member utilities are seeking to work collaboratively with vendors, and that program administrators are placing greater emphasis on both customer and vendor education.
The Motors Decisions Matter website atwww.motorsmatter.org, features a report prepared by the CEE titled “Premium Efficiency Motors and Adjustable Speed Drives in the US and Canada, May 2007.” This document features dozens of energy-efficiency programs that promote premium-efficiency motors, motor management, motor systems optimization, and/or ASDs in both industrial and commercial facilities. The report also includes a helpful appendix containing an overview of program types and related terminology. There, the reader will find explanations of prescriptive, new construction, custom, and standard performance contract programs as well as insights into technical and financial assistance, and education and awareness initiatives.
DRIVING TOWARD SAVINGSIn some situations, adding an ASD is a more sensible solution than just replacing the motor with a more efficient model. Drives are generally suggested for motor and load systems that deliver rated output less than 40% of the time, or where the average output is less than 60% of the rated output.
In addition to saving energy, drives can offer greater control over motor speed, which can prolong motor life and reduce maintenance costs. Drives can also increase productivity by empowering more precise control of process operations, which can result in higher product quality. In certain applications, the installation of drives can enable load-shedding strategies that can benefit from demand-response programs, which are playing an increasingly important role in maintaining grid reliability in the face of steadily growing electricity demand.
The Database of State Incentives for Renewables & Efficiency (DSIRE) website atwww.dsireusa.orgis one of many sources to consult when seeking financial incentives for energy-efficient motors and drives. DSIRE is an ongoing project of the North Carolina Solar Center and the Interstate Renewable Energy Council (IREC) funded by the DOE. As its name suggests, the database includes both renewable and energy-efficiency incentives and can be searched by state, eligible sector, implementing sector, incentive type, or technology.
Finding one or more potential funding options on DSIRE or any other website is just the first step - it’s also important to do the necessary homework to make sure the proposed upgrade will actually qualify for an incentive. In the case of ASDs, for example, programs typically limit incentive eligibility to certain horsepower motors, minimum operating hours, and/or minimum estimated energy savings per year. Some programs go even further and require that any existing throttling device (e.g., inlet vane, bypass damper, or throttling valve) be removed or permanently disabled before the drive incentive is paid.
Whether a facility contains thousands of motors or just a handful, it pays to stay up-to-date on ways to improve motor-system efficiency and any incentives that might be available to help you do so.ES