Thinking About Power Factor Correction?

There appears to be a great deal of interest in power factor correction these days, if the volume of inquiries that I get is any measure. In VERY simple terms, “power factor correction” optimizes the way that electric power is consumed by motors, fans, pumps, and other apparatus. Is power factor correction a good thing? Yes. Is it the first or best initiative to be pursued by a facility that seeks to reduce its energy costs? Not always.

A bit more explanation is needed. Electricity provides a “basket” of three services, which include voltage, frequency, and current supply. The steadiness and predictability of these services are the key to optimal power consumption and the efficient operation of electricity-dependent equipment. Motors and other electronics suffer damage caused by poor power quality, such as deviations in the supply of voltage or frequency. Weak currents starve these loads of power, causing motors to overheat, and thus suffer premature failure.

Power utilities, especially those that are seeking to offset the need to build more generating capacity, like to promote power factor correction as a way to maintain the overall demand placed on their system. And depending on the structure of electricity tariffs, utility customers opting for this service may enjoy lower power bills. Industrial engineers find it attractive for several reasons: (1) the task can be achieved quickly; (2) the cost-benefit can be very positive, and (3) the task imposes little or no interference with facility operations or behavior. In other words, power factor correction is a one-time “project” that doesn’t require a lot of coordination across departments.

Now here’s the issue: is an old clunker made valuable by giving it a fresh coat of paint? This CAN be the situation set up by the promise of power factor correction. For example, let’s say a facility operates a set of five air compressors. A thorough energy analysis may indicate that only three compressors are needed after the facility implements a leak detection/repair protocol and converts some compressed air functions to less-costly alternatives. Power factor correction, in this case, needs to be applied only to three units, while the other two units can be removed and the floorspace used for other activities.

Similarly, the return on investment for power factor correction is inflated when it is applied to capacity that could be avoided. In other words, it doesn’t make sense to optimize a power supply that ends up being wasted. Show me a plant where oversized motor drives are left running during breaks, and I’ll show you a very attractive rate of return on a power factor correction job.

This is by no means a testimony against the concept of power factor correction or the many good professionals that provide this service. Almost every plant will benefit from power factor correction. But would it not make sense to improve energy “housekeeping” first by eliminating waste and redundancies, right-sizing equipment, and establishing energy-smart operating procedures?