Transforming Today's Transformers

Beginning in 2009 or 2010, electrical contractors are likely to see a new breed of higher-efficiency liquid-filled distribution transformers hitting the market, thanks to new standards expected to be announced by the U.S. Department of Energy (DOE) in September. Efficiency requirements could climb even higher in 2013, if a proposal supported by electric utilities and environmental groups is included in September’s ruling.

The new standards would be included among the appliances and commercial-equipment standards administered by the DOE’s Office of Energy Efficiency and Renewable Energy. The standards would apply only to liquid-filled transformers. New dry-type transformer standards went into effect in January of this year.

Transformers that meet the current National Electrical Manufacturers Association (NEMA) Type 1 standards already are pretty efficient, with ratings ranging from 98.1 to 99.45 percent, according to DOE figures from August. The initial efficiency upgrade would boost ratings to between 98.4 and 99.45 percent. These improvements may seem minimally important, but even a .01 percent rise in efficiency can mean big energy savings when multiplied by the 41 million distribution transformers now operating throughout the nation’s electricity grid.

In fact, the DOE estimates U.S. energy savings could total 2.39 quadrillion Btus in the 28 years following the standards’ adoption. Additionally, greenhouse gases and other pollutants related to avoided energy losses would be eliminated.

Unlikely teammates

An unlikely alliance uniting investor-owned utilities through their trade association, the Edison Electric Institute (EEI), the American Public Power Association (APPA) and the Natural Resources Defense Council, among others, is pushing the DOE to enact even higher performance targets by 2013. These goals would range from 98.48 to 99.6 percent, based on unit size and design.

EEI, APPA and the environmental groups offered their proposal at February’s National Association of Regulatory Utility Commissioners’ (NARUC) annual meeting, and NARUC also endorsed the measure. The language represents a compromise between industry members and environmentalists. Originally, environmentalists were pushing for faster enactment of the tougher standards. Utility representatives countered with the suggestion that the lower standard, called TSL 2, be enacted in 2009—a year earlier than DOE’s suggested 2010 date—in return for the 2013 adoption of the more stringent TSL 4 standard.

Getting EEI and APPA on board is crucial to large-scale adoption of the tougher standards because of the power these groups’ members wield in the distribution-transformer market. Investor-owned and municipal power companies purchase approximately 80 percent of all distribution transformers in the United States, according to Edward Comer, vice president and general counsel of EEI.

Costs are a concern for many utilities now involved in advanced meter-reading and smart-meter replacement efforts.

Transformer manufacturers are concerned costs for TSL 4 models still may be higher than utilities are anticipating, even with the added development lead time. Achieving higher efficiency ratings means adding more copper and core steel to existing designs, and those materials have become increasingly expensive over the past several years.

Henry Hecker, global product director, Transformer Products and Fluids, with Cooper Power, noted that managers at one major steel supplier have stated their company would need to spend $200 million to $300 million to upgrade plant capacity to meet the added demand TSL 4 mandates could encourage, and such improvements would take two to three years to complete.

The DOE has stipulated that recommissioned transformers that do not change ownership will not be affected by any new efficiency standards. So, in the short run, Hecker suggests utilities may rely more heavily on repairing existing transformers rather than replacing them with more efficient—and expensive—new models. Many larger utilities have their own repair facilities, he said.

Contractors may see some added installation challenges with transformers meeting the TSL 4 standards. Because of the added copper and core steel, these units may be larger and weigh more than their older counterparts. This could raise support concerns on pole-mounted transformers and create problems with submersible installations, if the new unit is larger than an existing vault.

Despite cost and potential installation concerns, most involved in specifying or manufacturing transformers believe the new standards will go forward.

“I think the legislation is going to happen,” Hecker said. “This is one step to improving the efficiency of the U.S. electricity system.” EC

ROSS is a freelance writer located in Brewster, Mass. He can be reached at


About the Author

Chuck Ross

Freelance Writer

Chuck Ross has covered building and energy technologies and electric-utility business issues for a range of industry publications and websites for more than 25 years. Contact him at

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