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Soy moves from tofu to electrical transformers

To reduce the risk of explosions and pollution, some utilities are switching from petroleum to vegetable oils to insulate transformers.

The lowly soybean has found a calling higher than tofu and tamari sauce. It's being used to insulate equipment bringing electricity to millions of homes.

More than 100 utilities are using soy-based oil as a safer, eco-friendly alternative to petroleum coolants in electrical transformers, which convert high-voltage power from a plant to a lower voltage for consumers.

Supporters of soy instead of mineral oil for electrical transformers hope to prevent fires that happen almost daily around the United States.
Supporters of soy instead of mineral oil for electrical transformers hope to prevent fires that happen almost daily around the United States. Coastal Electric Cooperative

Fires occur nearly every day around the country due to problems with transformers, say proponents of soy oil. On May 2, flames leapt 15 feet above street level through a manhole in Cambridge, Mass, temporarily shutting down Harvard Square.

Soy oil is less flammable than those from petroleum and, if aflame, burns for less time.

"If you have a catastrophic failure from any source, from lightning or an explosion or whatever, you want this oil to be there," said Glenn Cannon, director of the Step Up coalition urging utilities to switch to soy. "Do you want to be the utility that has a toxic fire all over the place, or do you want to say, 'This is soybean food grade oil?'"

Soy oil also helps transformers to perform better and last twice as long as others, he said.

Cannon is a former manager of Iowa utility Waverly Light and Power and holds five patents on vegetable-based oils. He began exploring soy following a 1994 spill of 20 gallons of petroleum transformer oil that cost Waverly nearly $30,000 to clean up PCBs and other contaminants.

Annual U.S. consumption of transformer oils amounts to some 60 million gallons, he said. Electricity providers in Spain and Norway are big customers of soy oil, whose demand rose by 80 percent between 2006 and 2007, according to Cooper Power Systems, which makes high-voltage electrical hardware for utilities.

Agricultural giant Cargill provides soy-based Envirotemp FR3 fluid to Cooper Power Systems, which uses and sells it to other transformer manufacturers.

Spent soy transformer oil is recyclable for use in biofuel or for lubricants used in trucks, said Cannon.

Mineral-based transformer oil, on the other hand, contains cancer-linked ingredients and pollutes ecosystems when spilled. Every year, 250,000 gallons of the fluid leak from electrical equipment, according to Step Up. Thousands of gallons poured into the ground and waterways due to Hurricane Katrina, but the EPA didn't require utilities to report the mess because a national catastrophe was involved, Cannon said.

Long a staple of so-called health food stores, soy is increasingly called upon for mechanical and industrial applications. It's well known and controversial as an ingredient in biofuels.

Companies exploring alternatives to petroleum for other industrial oils include Green Earth Technologies, which sells 'green' motor oils for cars and boats that is made from waste animal fats.

Step Up stands for Safer Transformers, Environmental Protection, and Upgraded Performance.