Friday, January 05, 2007

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?



At 2:46 AM, Anonymous Anonymous said...


I feel that your comment " an old clunker made valuable by giving it a fresh coat of paint?" is not a very good analogy when it comes to Power Factor Correction. I feel that PFC is more like giving an old clunker a good tune up. And you’re right, just because you give this clunker a tune up doesn’t mean that the water pump or exhaust system still don’t need to be replaced. Or that the guy that owns the car shouldn’t take better care of it. But it does make the car rum more efficiently and uses less energy to complete its task.

From time to time I have read articles like yours down playing the importance of PFC. Not that I don’t completely agree with you about the fact the Building Maintenance/Engineering Departments aren't extremely wasteful due to their lack of energy management training. But PFC is a great way to get to help reduce energy costs, not only for the building but also for our country as a whole. It also leads the way for Energy Management consultants to help correct the issues that you raised from the top down.

I feel that even if you are not completely convinced that Power Factor Correction in older facilities is the answer; that you would a least see it as part of the solution. And speak more in its behalf rather then against it.

Luke Stickney
Titan Electrical Construction, Inc.

At 11:19 AM, Blogger Christopher Russell said...

Mr. Stickney:
I appreciate your thoughful reply. That's what the blog is here for! Here's where I think we agree: you can't go wrong by improving power factor correction. I simply ask if it is the best "first step" in reducing a facility's energy costs. Sometimes it will be the best first step, sometimes it won't. An energy audit, usually written from a purely technical perspective, may suggest what things to do and the order in which they should be done. But technical agendas often clash with other organizational priorities. Compromises are made. As a result, we often see certain "difficult" energy choices being deferred. In some cases, power factor correction is "politically" easy to accomplish, perhaps because its installation is relatively non-disruptive (compared to swapping in an entirely new air compressor system, for example). For this and other practical reasons, PFC may move to the top of the list.


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