Biodegradable Bio-based Transformer Fluid—A Green Solution
Dielectric fluid is used to cool and insulate the inner workings of electrical transformers. For the past one hundred years, the vast majority of transformers used petroleum-based mineral oil, a dielectric fluid with both a negative environmental profile and relatively low flash and fire points.
Now more and more utilities are switching to a “green technology” alternative to petroleum-based mineral oils. This newer “bio-based” dielectric transformer fluid is sustainable, biodegradable, environmentally preferred, and less expensive to clean up. It has a more favorable carbon dioxide footprint and contributes to sustainability of resources. This new fluid uses edible vegetable-seed oils as its base.
In addition to offering a superior environmental profile, biodegradable bio-based transformer fluid offers the following benefits:
- Enhanced fire safety
- Enhanced pubic safety
- Enhanced transformer life
- Enhanced transformer performance
- Enhanced system reliability, resulting in fewer service interruptions and outages
What is Bio-based Transformer Fluid?
Biodegradable bio-based transformer fluid is a revolutionary insulating product that is safe for the environment and the public. It uses as its base food-grade soybean oil, which is classified as non-toxic according to a standard test method developed by the Organization for Economic Cooperation and Development (OECD), a worldwide standard-setting body.
Bio-based fluid is biodegradable based on testing done by the United States Environmental Protection Agency (USEPA). U.S. Environmental Protection Agency’s Environmental Technologies Verification (ETV) results place the fluid in the most biodegradable category. ETV reports on this fluid were the first utility equipment materials ever published by the USEPA.
In addition, The National Institute of Standards and Technologies BEES (Building for Environmental and Economic Sustainability) evaluation favorably rates biodegradable bio-based fluid regarding its total lifecycle environmental and economic impact, which includes a CO2 footprint roughly one-third the size of that imposed by petroleum-based mineral oil.
Besides its favorable environmental profile, biodegradable bio-based fluid offers many benefits over traditional dielectric fluid (non-conductive fluid used to insulate and cool electrical distribution products such as transformers), including improved fire safety, enhanced performance, increased system reliability, and equipment life extension.
How is Bio-based Dielectric Fluid Made?
Biodegradable bio-based fluid is formulated from edible vegetable oils and food-grade and other benign performance-enhancing additives. It does not contain any petroleum, halogens, silicones, or any other environmentally questionable material. Bio-based fluid biodegrades more than 99 percent, while petroleum mineral oil biodegrades 21 percent when outside a transformer. In one of the most sensitive tests for toxicity, the world-recognized OECD acute aquatic toxicity test method, biodegradable bio-based fluid exhibited exceptional performance. Some manufacturers even tint their biodegradable bio-based fluid green to reflect its favorable environmental profile and to distinguish it from mineral oil.
Biodegradable bio-based transformer fluid has an exceptionally high flash point of 330 ˚C (compared to 145˚C for petroleum-based mineral oil). It is listed as a Less-Flammable Dielectric Liquid by FM Global (FM) and Underwriters Laboratories® (UL) for use in complying with the National Electric Code® (NEC) and insurance requirements. Inclusion in this list typically means that distribution substation transformers filled with bio-based fluid may be installed indoors in commercial and industrial facilities.
Excellent performance of bio-based fluid has been confirmed in more than 50,000 field installations beginning in 1997, with no reported transformer fires. The fluid is also used in retrofill applications for transformers and other fluid-filled distribution and power equipment.