Energy Costs Got You Down?

Now is the time to improve efficiency and productivity of existing motor systems

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With the current economic climate putting a squeeze on capital budgets, now is the time to improve the efficiency and productivity of existing motor systems such as pumps, fans and air compressors.

According to a U.S. Department of Energy (DOE) study, the U.S. chemical industry consumed approximately 6.3 quads1 of energy in 2001. This amount represents approximately 6 percent of domestic energy use and about 19 percent of all U.S. manufacturing energy use for that year. DOE also estimates that greater attention to motor system management could reduce chemical plant energy consumption by as much as 18 percent.

Defining motor management

Motor management entails a variety of practices that capitalize on the benefits of premium-efficiency motors (lower operating costs and improved reliability) and best motor repair practices (maintain efficiency, optimal availability). It includes:

A decision-making protocol based on life-cycle costing for making purchase and repair/replace decisions.

Procedures to inventory and categorize motors.

Practical advice on making sure the optimal motor for critical applications will be available when needed.

Guidelines to ensure quality repair services.

Motor Decisions Matter, a national educational campaign, is working to spread the word about the benefits of motor management and premium-efficiency motors and to empower companies to adopt these practices. Campaign sponsors include motor manufacturers, utilities, energy-efficiency organizations, trade associations and governmentagencies. (For more information, see www.motorsmatter.org.)

Figure 1. Motor Systems Energy Use

Source: Xenergy study, 2001

Motor management importance

Over a motor's lifetime, its electric bill accounts for over 97 percent of its total cost. Less than 3 percent of the lifetime cost goes toward its purchase, installation and repair. For example, consider a 75-horsepower (hp) motor running at full load for 6,000 hours per year. A typical purchase price would be approximately $4,000. Over its 10-year life, however, that same motor would cost $220,000 to run (based on $0.075 per kilowatt-hour [kWh]).

It becomes apparent that small increases in efficiency translate into big savings. In this example, a one percent increase in motor efficiency translates into $2,800 in energy savings over that time ," nearly the cost of the motor.

Implementation of a motor management plan often improves productivity. The first step to plan implementation is to gain an understanding of your motor fleet and to catalog it. One of the benefits of this review process is that it quickly identifies applications with older inefficient motors and improperly sized motors that should be replaced based on their economic performance. The economic analysis also will indicate whether these motors should be replaced immediately or upon failure. Plants that have large motors and motors running critical processes stand to gain the most from the review in terms of economic return and reduced downtime.

Motor management also could reduce downtime attributed to motor failure. Premium-efficiency motors typically are constructed with superior materials and have more copper, tighter tolerances and longer warranties.

Figure 2. Motor System Energy Use within SIC 28

Source: Xenergy study, 2001

The management plan

Identification of appropriate applications for premium-efficiency motors is an important component of every motor management plan. An understanding of what motor efficiency levels are available and how to specify them is equally important.

Working closely with the National Electrical Manufacturers Association (NEMA), also a campaign sponsor, the Consortium for Energy Efficiency established a premium-efficiency specification and brand, called NEMA Premium, which motor manufacturers, distributors, repair shops, energy efficiency organizations and motor incentive program administrators now embrace. (For more information, see www.nema.org/premiummotors.)

Motor repair quality also is an important consideration when analyzing motor repair/replacement decisions. Proper evaluation requires a comparison of total repair costs (repair plus energy and life-cycle operating costs) with total replacement costs with a NEMA Premium motor (purchase plus energy and life-cycle costing) before you are able to determine which option will achieve the greatest economic return.

When the repair option is appropriate, you must exercise care to ensure all repairs do not deviate or deviate very little from the motor's original energy specifications because improperly performed repairs can decrease motor efficiency by as much as 2 percent. For more information about what constitutes quality repair and how to specify it for your motors, see the Electrical Apparatus Service Association (EASA) guidelines on best practice repair (www.easa.com, under Industry Resources).

Finally, motor management is about planning. Too often, repair/replace decisions are based on motor availability or short-term economics ," not long-range planning. Motor management provides the financial analysis tools you need to make good motor decisions and offers direction for developing cost-effective, pro-active purchasing and repair/replace policies. The Motor Decisions Matter Web site (www. motors matter.org) offers a motor planning toolkit to help you get started on development of your facility's plan.

Figure 3. SIC 28: Distribution of Motor Population and Energy (by hp)

Source: Xenergy study, 2001

Savings opportunities

Motor use accounts for 59 percent of all electricity used in manufacturing. The following information is taken from Small Chemicals and Allied Products Manufacturers: a Profile of Motor Energy Efficiency Opportunities, a study commissioned by the Consortium for Energy Efficiency and conducted by Xenergy in 2001. It gives an indication of where chemical processing plant personnel might find energy and related savings.

The chemicals and allied products industry (SIC 28) is the largest user of motor systems energy, accounting for 20 percent of the total industrial motor system energy use. See Fig. 1.

Within the chemicals and allied products industry group, SIC 28, the breakdown for motor system energy is even more pronounced, with four of the industries within this group comprising more than 75 percent of the total motor system energy use. See Fig. 2.

The distribution of motors within this industry group also is telling of the potential for increased motor efficiency, as the largest number of motors in the chemicals and allied products industry are those with hp levels between 1-5 (see Fig. 3), and the vast majority of all the motors in this industry are less than 50 hp.

As shown in Fig. 4, the largest motor-use applications (in terms of numbers of motors) within the chemicals and allied products industry are pumps and material processing. However, the application using the most energy is compressed air, followed closely by pumps and material processing. These areas represent the greatest potential sources of efficiency upgrades.

Figure 4. SIC 28: Distribution of Motor Population by Application and Energy Use

Source: Xenergy study, 2001

Getting started

A motor management plan puts plant decision-makers in the driver's seat to make the most cost-effective decisions when motors fail. By considering electric motors as a cost of production in the same way American industry looks at labor costs and material costs, these decision-makers could improve their facilities' overall efficiency and bottom line.

For more information about Motor Decisions Matter, visit www.motorsmatter.org, or contact DOE's Office of Industrial Technologies Clearinghouse at (800) 862-2086. Visit www.chemicalprocessing.com for an expanded version of this article, which includes a motor management case study.

Jones is the industrial program manager for the Consortium for Energy Efficiency, and Mason is an industrial program associate for the consortium. Contact them at (800) 862-2086.

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