Transformer costs

I am writing you with concern about significant errors in the Pure Power article “Calculating the 'Real' Cost of Ownership for Transformers” (Spring 2009, page 20) by Thomas Patzner and Wendell Leisinger.

The article is a disservice to readers seeking to reduce electricity waste. It overstates cost and underestimates savings of higher efficiency transformers, thereby making the wrong lifecycle cost conclusion. This is all the more troubling given the article's title. If the cost of high-efficiency CSL-3 transformers was truly as much as the article indicated, it would be hard to understand why ASHRAE would recommend CSL-3 transformers in its “Design Guide for Energy Efficient K-12 Schools, ” along with a growing list of other state government organizations. Fortunately, for those seeking to reduce energy use and save money, the lifecycle cost of CSL-3 transformers is lower, and offers real economic and environmental benefits.

Before forming their own conclusion, readers ought to note Patzner and Leisinger have cited no source for the price listed for the CSL-3 transformer. The data of the referenced TP1 transformer reflect the EE75T3H model that their company, Square D , manufactures; one would expect the authors to be familiar with their own company's products.

In fact, the $5,000 higher purchase price attributed to the 75kVA CSL-3 transformer has been substantially overstated. For example, not only does Powersmiths' E-Saver C3 (CSL-3) 75kVA transformer sell for less than the article claims, it sells for less than the cost the authors cite for their own reference TP1 transformer. This being the case, why wouldn't you always purchase the higher efficiency CSL-3 transformer?

Since payback equals incremental first cost divided by annual savings, overestimating incremental cost and underestimating savings will overestimate the payback period.

While there will always be buyers willing to sacrifice lower lifecycle costs for lowest first cost, going beyond minimum legal performance is the only way to make progress toward energy and climate goals of the country.


Authors respond

We thank Mr. Ling for responding to our article and emphasize that the cost of ownership example provided in the article was simply that—an example. Each project is unique, and is composed of many variables that a consulting or specifying engineer must take into account prior to specifying a transformer, including building type, local electrical rates, and client desires.

The allotted space for the article did not allow us to delve deeply into these—and other—common variables. But the larger issue is the fact that engineers must review project-specific variables as stringently as possible during the specification process, and make the most educated decision possible. The formula provided in the article is certainly not all-inclusive; it can—and should—be augmented to include localized variables. The result of the formula will then suggest the transformer that best meets the client's needs, and provides the most manageable cost of ownership throughout the lifecycle of the building.

Thomas Patzner Staff Product Specialist LV Transformer Business

Wendell Leisinger Customer Segment Manager Consulting Engineers Schneider Electric

Final word

Of course, users should do due diligence, but being busy, users would benefit more from a more representative example than what was given in the article.

As a reality check, both TP1 and C3L 75 kVA transformers are available for under $5,000, far below the $10,000 to $15,000 quoted in the article. As a result, the real price gap is small enough that the incremental cost is often recovered within a couple of years, not bad for a 40-year product. A very different conclusion than the article's example, and one that's much more representative of day-to-day projects.

Philip J.A. Ling , P.Eng., LEED APv.P. Technology Powersmiths International Corp.


Send your letters to Michael Ivanovich, editor-in-chief, Consulting-Specifying Engineer , 2000 Clearwater Drive, Oak Brook, IL 60523, or via e-mail to michael.ivanovich@ reedbusiness.com .

Letters should be no longer than 200 words, and may be edited for space, style, spelling, and grammar.

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