A better sustainable solution—biodegradable bio-based fluid.
The biodegradable bio-based transformer fluid developed in recent years is a superior “green technology” alternative to petroleum-based mineral oil. Petroleum-based mineral oil is highly flammable at 145°C (around 300°F), costlier to clean up in case of spills, and harmful to the environment.
And while today’s mineral transformer oils are highly refined, there are hundreds of millions of gallons in existing older transformers that contain significant quantities of polynuclear aromatics. According to a U.S. Environmental Protection Agency (EPA) Environmental Technology Verification (ETV) Report*, the primary component of this mineral oil-based transformer fluid was a hydrotreated light naphthenic petroleum distillate**, ranging from 30 to 100%. Due to this content, such oil “was identified as an International Agency for Research on Cancer (IARC) confirmed carcinogen based on experimental data for animals.”
*EPA 600/R-02/042
**Chemical Abstract Service (CAS) No. 6472-53-6
Cleaner, safer, better.
By comparison, bio-based fluid is biodegradable and non-toxic, resulting in an environmentally preferred, and less expensive, fluid to clean up. It provides enhanced transformer performance by extending the life of existing equipment. In addition, 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.
This listing means that distribution substation transformers filled with bio-based fluid may be installed indoors in commercial and industrial facilities, and safely outdoors in highly populated areas such as schoolyards and shopping centers.
Let’s take a closer look at what this means:
- Bio-based fluid is highly biodegradable according to U.S. EPA Environmental Technological Verification (ETV) testing. This means that it is unlikely to persist in the environment. In comparison, mineral oil contains compounds that are resistant to biodegradation, requiring the kind of responses the electric utility employed in the Fairfax County, Va. spill.
- As a Less-Flammable Dielectric Liquid, bio-based transformer fluid improves public safety. In more than 50,000 field installations since 1997, there are no reported fires.
- Bio-based fluid compounds are essentially benign when introduced to the environment. What’s more, because bio-based fluid creates a lower likelihood of fire, there’s an even lower chance that it will find its way into the environment at all. Even if a fire occurs, a resultant bio-based fluid leak would have minimal impact on the surrounding environment.
SIDE-BY-SIDE COMPARISON
Bio-based Dielectric Fluid (Vegetable Oil)
Petroleum-based Mineral-oil Fluid
Produced from domestically grown, renewable sources, such as soybeans and corn
Produced from increasingly scarce and non-renewable special petroleum crude
Highly biodegradable; non-toxic; does not contain petroleum, silicone, or halogens
Contains compounds that do not readily biodegrade. May contain traces of a confirmed carcinogen*
Relatively rapid biodegradation may eliminate the need for environmentally related clean-up operations
Spill clean-ups are required by regulation and typically necessitate special equipment and material to help capture contaminated runoff
360°C (680°F)
155°C (311°F)
330°C (626°F) Extremely resistant to ignition
145°C (293°F) Can catch fire at a relatively low temperature
Higher fire point reduces the frequency and impact of transformer fires; virtually eliminates sustained fires
Catches fire more easily, leading to higher probability of transformer fires
Proven to slow down the aging rate of the insulation system, resulting in an increase in the expected life of a transformer by decades; also promotes automatic dry-out of paper insulation
Does not slow down the standard insulation aging rate; requires special and expensive processing to dry out the paper insulation
Upfront investment promotes transformer life and leads to longer-term economic benefits
Smaller investment leads to shortened life of transformer and diminished economic returns; increases liability
*While today’s mineral transformer oils are highly refined, there are hundreds of millions of gallons in existing older transformers that contain significant quantities of polynuclear aromatics. According to U.S. Environmental Protection Agency (EPA) Environmental Technology Verification (ETV) Report EPA 600/R-02/042, the primary component of this mineral oil-based transformer fluid was a hydrotreated light naphthenic petroleum distillate, ranging from 30 to 100%. Due to this content, such oil “was identified in Chemical Abstract Service (CAS) No. 6472-53-6 as an International Agency for Research on Cancer (IARC) confirmed carcinogen based on experimental data for animals.”
Click here to see a partial list of responsible utilities that are adopting the use of biodegradable bio-based fluid.