“Green” Transformer Oil

Foods made with soybeans are a favorite among health-conscious consumers these days, but it turns out that the soybean also packs the potential to reduce the environmental risk and cleanup costs associated with traditional transformer oils used by the utility industry.

BioTrans™, a soybean-based electrical transformer oil developed by Iowa’s Waverly Light & Power, is a biodegradable, nontoxic, earth-friendly alternative to petroleum-based transformer oil designed to meet or exceed all standard transformer oil performance requirements.

TVA’s Public Power Institute is sponsoring advanced laboratory tests and field demonstrations on BioTrans at Nashville Electric Service (NES), a municipal utility. NES, the second largest distributor of TVA power, has installed six transformers at a residential development to compare the performance of the two types of oil. Three of the transformers are filled with BioTrans and three with a petroleum mineral oil. Side-by-side comparisons will help determine how well the soybean-based oil performs in the TVA region.

Transformers contain two or more coils of wire to change the voltage of electricity. The coils are submerged in cooling oil, which must not conduct electricity and must be stable over a wide range of operating temperatures.

So far, the results have been very encouraging. Tests indicate that in certain applications, BioTrans can be an excellent alternative to mineral-based oils, with the additional safety feature of higher fire and flash points. The soybean-based oil comes from an abundantly available renewable resource, breaks down readily in the natural environment, and can be reused as an industrial lubricant.

Over 151.4 million liters (40 million gallons) of transformer oil is used in the U.S. each year. Much of this usage occurs in or near environmentally sensitive areas such as rivers, lakes, and wetlands. If BioTrans proves to be a reliable alternative to current transformer oils, the benefits would include a cleaner environment, substantial cost savings to the utility industry, and increased profits for the U.S. agricultural industry.