FACT: "The AC induction motor typically operates at 80% efficiency when under full load, but the efficiency drops dramatically at lower loads."
Electric motors use more than half of all electricity -- roughly $300 billion per year worldwide. According to Rocky Mountain Institute's (RMI) 439-page E-Source report, The State- of-the-Art: Drive power, between 28 and 60 percent of U.S. drive power electricity, and between $25 and $50 billion, could be saved if motors and drive systems became more efficient. A typical industrial motor consumes electricity costing 10 to 20 times its initial capital cost each year! Because of this enormous operating cost, replacing inefficient motors with even slightly more efficient ones can repay the investment within 6 to 36 months.
RMI estimates the full use of appropriately sized, high-efficiency motors, adjustable speed drives, power factor optimization, fast speed controllers for turbo machinery, etc., holds the potential to save between 80,000 and 190,000 MW in the U.S., at an average net cost probably below half a cent per kwh saved. Capturing such huge savings will take decades, but could be accelerated with a combination of proper technical and financial support, particularly from electric utilities.
Numerous opportunities exist for development of industrial processes with greater efficiency through waste energy reduction, improved energy productivity and industrial cogeneration. The Pacific Northwest Laboratory estimates that up to 3 quads of low-temperature waste heat are recoverable through heat pump technology and as many as 3 quads of high-temperature waste heat are recoverable by advanced heat exchangers with improved design and materials. Ongoing R&D is necessary to tap this full potential.