Motor Summit 2014: Energy efficiency focus is on total motor systems
Presentations at this biennial technology conference showed growing movement to embrace work on the larger electrically driven system beyond the motor itself. This approach can enable large efficiency gains. Motor Summit was hosted by European and international energy associations and co-hosted by the National Electric Manufacturers Association (NEMA) of the U.S.
Motor Summit 2014, the 5th edition of this international conference dedicated to the promotion and development of efficient electric motor-driven systems, drew some 180 participants to Zurich, Switzerland, during Oct. 7-9, 2014. Energy requirements of motor-driven systems are estimated to be about 46% of total electric power generated worldwide—even substantially higher in some countries and in industrial sectors. That makes energy efficiency a topic of vital importance today and going forward. Motor Summit provided the platform for experts and interested parties to present and discuss technologies and strategies needed to make energy efficiency improvements possible.
Motor Summit was hosted by the Swiss Agency for Efficient Energy Use (SAFE) in collaboration with the Electric Motors Systems Annex (EMSA) of the International Energy Agency's Implementing Agreement Energy Efficient Electrical End-Use Equipment (IEA 4E).
Co-host for the event was the National Electric Manufacturers Association (NEMA) www.nema.org of the U.S.
Motors and more
It has become increasingly evident over prior editions of Motor Summit that the "system" beyond the electric motor represents fertile ground for large energy efficiency gains. Here we are talking about pumps, fans, compressors, drives (the core motor system)-as well as gearboxes, piping/heating systems, and other motor-driven loads (the so-called total motor system). Several summit presentations stressed the need for efficiency improvement at the system level (see Refs. 1, 2, 3).
Reference 4 described efficiency assessment of motor systems including mechanical transmissions (drive belts, gearboxes with various gear types) and pump/fan loads where 30% or greater efficiency gains could be obtained. Ongoing work on efficiency measurements for combinations of motors and variable-speed drives (VSDs) was presented in Reference 5, including partial load results using a 20-point test regime. Three motors types and sizes (IE2, IE3, IE4-permanent magnet at 7.5 kW, 37 kW, 75 kW) and VSDs comprised a total of nine test elements or "power drive systems." Partial load motor system efficiency assessments are particularly important since information of this type remains scarce. Results can be shown as contour curves of torque-speed efficiency, which offers useful interpretation (see Figure 1). IE motor classifications are explained below.
Another common theme of the conference involved strategies needed to overcome market barriers holding back wider use of highly efficient motor systems. Barriers mentioned (Refs. 2, 6) included:
- OEMs' exclusive concern for lower cost components
- Total cost of ownership not considered
- Motors often oversized, leading to low efficiency at partial loads
- Little influence of plant equipment users on management buying decisions.
Further barrier issues were mentioned for the China market, among them lack of awareness of system efficiency, lack of effective measurements and tools, and lack of trust for calculation of energy savings (Ref. 7).
The Oct. 2014 publication of "Toolkit for Policy Makers" from EMSA IEA 4E was made available at the conference. This significant milestone is Part 2 of an overall Policy Guidelines for Electric Motor Systems project-with Parts 3 to 6 under development. The report is available at www.motorsystems.org.
For their part, motors—particularly industrial workhorse ac induction machines—have made great strides in raising their efficiency through improved design and standardized testing, pushed by the enactment of mandatory minimum energy performance standards (MEPS). The U.S. has led the MEPS effort, followed by Australia and Canada, among others, with more nations heading to adopt MEPS. The types of motors currently covered under the amended U.S. regulation have been expanded to include virtually all categories of polyphase continuous-duty motors from 1 to 500 hp (0.75-375 kW).
In the European Union, stage 2 of a MEPS initiative will kick-in on Jan. 1, 2015, which makes mandatory the use of IE3 efficiency motors in the 7.5-375 kW power range. Stage 3 in January 2017 will extend the range of compliance down to 0.75 kW for IE3 motors. However, both stages allow an option to use IE2 motors if fitted with a variable speed drive. IE designation of motors refers to International Electrotechnical Commission (IEC) standard 60034-30 "International Efficiency (IE) Classes," which defines increasingly higher efficiency motor designs up to IE4 and makes provision for an IE5 class.
An IE3-class motor translates approximately to NEMA Premium efficiency level. For example, a 200 hp (150 kW), 4-pole 60 Hz NEMA Premium motor has a required nominal efficiency of 96.2% at full load. A comparable 160 kW, 4-pole 50 Hz IEC IE3 motor must provide 95.8% nominal efficiency. Motor designs of IE5 and even higher efficiency classes are under development.
While the progress to higher efficiency (IE3 class) motors outside the U.S. is a positive ongoing effect, global market transformation is expected to be slow due to the long life of electric motors and their huge installed base. This was made clear in the presentation "Motor market update" by Alex Chausovsky, manager and senior analyst, industrial automation, at IHS Technology in the U.S. (Ref. 8). IHS estimates that 60% of motor units in use worldwide in 2013 still remained IE1-a class no longer permitted for entry into the market in countries with mandatory MEPS in place.
As for current market size, IHS put the 2013 worldwide shipment of low voltage integral hp motors at 50 million units with average sale price of $300.
A regional breakdown of motor efficiency classes in use is summarized in the table below.
In addition, Ajit Advani of the CopperAlliance, India, added that the Indian motor market stands at about 12%-13% penetration for IE2 motors and less than 2% for IE3 motors. www.copperindia.org
Pursuing the course of mandatory MEPS in regions with small penetration of efficient motors makes economic sense. This approach will take considerable time. The start of mandatory IE3, scheduled for 2015 in Japan and for 2017 in China (Refs. 9 and 7, respectively), should lend impetus to the movement. Brazil expects to be on the IE3 MEPS track by 2018 (Ref. 10).
Retirement of old, inefficient motors presents another barrier to energy efficiency because of long product life and a large installed base. Figure 2 provides one glimpse of motor age from an analysis of 18 industrial plants in Switzerland (Ref. 2). The study found 56% of 4,142 motors older than their operating life expectancy. Similar findings are likely in other countries.
"The way forward" from this situation includes convincing upper management to invest in energy efficiency and promoting greater user awareness through education about potential savings, including life-cycle cost assessment, noted Rita Werle, representing the Swiss Agency for Efficient Energy Use and Topmotors, Switzerland.