Cutaway image of a NEMA Design B Premium efficiency motor. The Copper Development Association notes that all motors experience losses (the energy "fees" a motor charges as part of the electrical-to-mechanical energy conversion process), but the magnitude of the loss varies, even among motors of the same make, type and size. In general, losses are higher for standard-efficiency motors (pre-EPAct) than for motors that meet EPAct energy-efficiency standards. Motors that meet or exceed NEMA Premium efficiency standards have even lower losses. (Photo courtesy of Emerson Motor Company)
The American Council for an Energy-Efficient Economy (ACEEE) and the National Electrical Manufacturers Association (NEMA) have jointly developed and recommended new electric motor standards for Congress to consider in upcoming energy legislation. The proposed standards will help foster more widespread use of both energy-efficient and NEMA Premium efficiency motors, which have even higher efficiencies than either standard motors or those specified as energy efficient in the 1992 Energy Policy Act (EPAct).
This past spring, ACEEE and NEMA submitted their recommendations to the House Energy and Commerce Committee and the Senate Energy and Natural Resources Committee for their consideration in preparing new energy bills. The two organizations recommended that efficiency standards be established or increased for three categories of electric motors no later than 36 months from the date of enactment of new energy legislation.
Both ACEEE and NEMA have worked with the U.S. Department of Energy's Industrial Technologies Program (ITP) to help industry save energy and money in motor-driven and other industrial systems through information, tool development, and collaborations on technical projects.
Neal Elliott, industrial program director at ACEEE, points out that significant energy and cost savings will be possible under the new standards.
"These standards will provide major energy and cost savings to industrial and commercial motor users while helping to moderate the growth in electricity demand in this country," Elliott says. "In the industrial sector, motors account for more than two-thirds of the electricity consumed. These standards will save more than 8 trillion kilowatt-hours by 2030, with a net cost savings to electric consumers of almost $500 million."
Replacing older, less-efficient motors increases both motor efficiency and energy cost savings. (Graphic courtesy of Washington State University Extension Energy Program)
First, ACEEE and NEMA recommend increasing current mandatory minimum efficiency standards for general-purpose, integral-horsepower induction motors to "NEMA Premium" efficiency standards (see Table 12-12 in NEMA Standards Publication MG-1, 2006) (PDF 199 KB). Download Adobe Reader. This efficiency level is already a requirement for new motors in federal facilities, under the purchasing guidelines of the Federal Energy Management Program.
Second, they propose establishing energy-efficient motor standards for seven types of low-voltage, polyphase, integral-horsepower induction motors not currently covered under federal laws. Specifically, they propose no longer excluding the seven motor classes that were excluded in 1992 EPAct standards for electric motors of 1 to 200 horsepower (hp). The seven classes are U-frame, NEMA Design C, close-coupled pump, footless, vertical solid-shaft-normal thrust and 8-pole (900 rpm) motors, and all polyphase voltages up to 600 volts (other than 230- and 460-volt motors). This modification extends the coverage of the minimum energy-efficient motor standard to 200- and 575-volt motors.
Third, they propose that NEMA Design B, general-purpose, 201- to 500-horsepower motors meet minimum full-load efficiency values for energy-efficient motors. These values are specified in Table 12-11 of NEMA Standards Publication MG-1, 2006 (PDF 199 KB). Download Adobe Reader.
ACEEE and NEMA have also recommended that motor manufacturers and end-users receive federal tax credits for producing or buying premium-efficiency electric motors even before the new standards take effect. This would help expedite production and use of the motors, and it would provide environmental benefits in terms of lower electricity use and fewer greenhouse gas emissions.
Since most premium-efficiency motors have a useful life of more than 20 years, purchasing them now can help manufacturers start realizing benefits right away and for many years to come, according to ACEEE. The organization estimates that the tax credits would result in an additional 700 million kilowatt-hours and $40 million in savings.
"This agreement demonstrates the mutual benefits that industry and the energy efficiency community can accomplish by working together," says Susan Coakley, executive director of Northeast Energy Efficiency Partnerships (NEEP), which worked with ACEEE and NEMA on developing the proposed standards.
This article appeared in the Spring 2007 issue of Energy Matters .