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A new wave of products for power transformers offers cleaner, safer and more cost-effective alternatives to traditional petroleum oil.
A utility distribution transformer holds between a few gallons and several hundred gallons of oil, and when one spills it can spell environmental and economic disaster. "We had about a 20-gallon spill that cost us $27,000 to clean up," says Glenn Cannon, general manager of Waverly Light and Power in Waverly, Iowa. "I knew there had to be a better way."
That better way, he says, is transformer oil made from plant products. While transformer oils are not really considered lubricants, their development helps foster the production of bio-oils, which are increasingly finding uses as biofriendly and high-performance lubricants.
Bio-based oils-produced by such companies as Cargill and Cooper Power Systems and made from such renewable resources as rapeseed and soybeans-may offer a cleaner and safer alternative to traditional petroleum oils, Cannon says. he helped develop one of these bio-oils working with the University of Northern Iowa's Agriculture-Based Industrial Lubricants (UNI-ABIL) research group. Since 1998 Waverly Light and Power has installed only transformers that use bio-based oil.
In the United States newly manufactured transformers are free of PCBs (polychlorinated-biphenyl). But many older transformers aren't. As of 1994 about 200,000 U.S. transformers still used PCB-spiked oil, according to the EPA.
"About 40% of transformers still in use are PCB contaminated," says Cannon. "So there's a large amount of transformers that needs to be changed." EPA rules require that mineral oi spills-even if PCB-free-from transformers must be cleaned up. The new, plant-based oils may change all that and can offer other benefits as well, says Mike Rudek, process coordinator for Distribution Design and Standards at California's Sacramento Municipal Utility District (SMUD).
Like Waverly Light and Power, SMUD has committed to buy only bio-oil-filled transformers for its pole-mounted and pad-mounted applications. The utility will evaluate the performance of the bio-oil over the next four years, installing more than 10,000 transformers filled with about 680,000 gallons of oil. Other utilities, from Alaska to South Carolina to Dubuque, Iowa, and the Tennessee Valley, have installed scattered bio-oil transformers, but currently only Waverly and SMUD are eschewing mineral oils entirely, adds Cannon.
Bio-oil's environmental advantages, Rudek says, appealed to SMUD, whose customers...