FAQs

What is an electric transformer?

Often unnoticed by the public, transformers are used by utilities to deliver power from the generating plant to commercial and residential customers. Electric utilities are responsible for millions of transformers, which are most commonly installed on top of utility poles, on concrete pads in neighborhoods and shopping centers, under city streets, and in enclosed substations.

What is the lifespan of a transformer?

Depending on the location of the transformer and the power demands placed on it, the lifespan of mineral oil transformers averages around 30 years. Testing has shown that biodegradable bio-based fluids can increase transformer life up to four times longer than the standard.

What dangers do transformers present?

Transformers—not something most of us think about—can hold potential hidden dangers. Industry analysts report that transformer failures are common, and costly. The consequences of failure range from outages only to tank ruptures to explosions and fires. These events can harm people, equipment, property, and the environment. They can cause exposure of “hot” energized cables to people and animals. For the utility, a single incident can mean millions of dollars in damages and liability exposure, clean-up and remediation costs, and outages.

When transformers fail eventfully, our environment can suffer. Petroleum-based mineral oil spills are harmful to our environment, and are therefore highly regulated at both the state and federal levels. Due to their lower biodegradation rate, certain compounds of mineral oil can persist in the environment for up to decades.

In addition, some petroleum-based mineral oil in use today may contain materials identified by the EPA as a confirmed carcinogen.*

*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 percent. 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.”

What is dielectric coolant fluid, and why is it necessary?

Due to their high voltage, transformers are enclosed in metal tanks that must be insulated from their internal, live, electrical assembly. Their insulation system almost always includes the use of an electric coolant, known as dielectric fluid.

What is the environmental impact of coolant fluid spills and leaks?

Leaks and spills (common when a transformer fails) of petroleum-based mineral oil can have a harmful effect on the environment, killing wildlife and plants and contaminating streams and soil. Petroleum-based mineral oil lingers in the environment due to its low biodegradation rate. In addition, it can be very costly to clean up in the event of a spill.

This is unacceptable, because a far safer, fire-resistant, and biodegradable alternative exists: bio-based transformer fluid. If a spill or leak of bio-based fluid occurs, typically the fluid rapidly and completely biodegrades, virtually eliminating the need for hazardous material response.

What are the differences between petroleum-based mineral oil and biodegradable bio-based coolant fluid?

As the industry standard for more than 100 years, petroleum-based mineral oil coolant is the fluid most commonly used by electric utilities. That’s unfortunate, because it is not the safest nor is it the most economical coolant type on the market. The biodegradable bio-based transformer fluid developed in recent years is a superior “green technology” alternative to petroleum-based mineral oils. Petroleum-based mineral oils are flammable at 155˚C, costlier to clean up in the event of spills, and harmful to the environment. In addition, some petroleum-based mineral oil in use today may contain materials identified by the EPA as a confirmed carcinogen.*

In comparison, bio-based fluid is biodegradable, environmentally preferred, sustainable and less expensive to clean up. 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.

*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 percent. 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 (IRAC) confirmed carcinogen based on experimental data for animals.”

How is bio-based fluid turned into coolant fluid?

Biodegradable bio-based fluid is formulated from highly processed edible vegetable base oils and food-grade and other benign performance-enhancing additives. It does not contain any petroleum, halogens, silicones, or any other questionable material.

The biodegradation rate for bio-based fluid meets the requirement for EPA’s highest classification of “Ultimate Biodegradability,” while petroleum-based mineral oil does not even meet the requirement for the lesser classification of “Readily Biodegradable.” 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. One manufacturer even tints its biodegradable bio-based fluid green to reflect its non-toxicity and favorable environmental profile and to distinguish it from mineral and synthetic oils.

Are there incentives for states and cities to use biodegradable bio-based fluid?

Several states and municipal governments have recognized the advantages of biodegradable bio-based transformer fluid and have enacted legislation that provides incentives to electric utilities that use it. In 2006, Iowa Governor Tom Vilsack (D) signed into law legislation that provides a tradable tax credit for electric utilities that use a soy-based transformer fluid. Increasingly, elected officials are making long-term commitments to renewable energy resources and renewable fuels production and financially rewarding companies that choose to use renewable resources.

How many utilities nationwide use biodegradable bio-based fluid?

The nation’s leading utilities recognize that their mission includes more than being a reliable provider of energy services. It also means being a responsible member of the communities they serve and working to protect and sustain the environment. As an important part of fulfilling this commitment, many utilities have adopted the use of biodegradable bio-based fluid to some extent or exclusively. Several are also applying the fluid for network and power transformer installations, for both new and retrofilled existing units.

Click here to see a partial list of responsible utilities that are adopting the use of biodegradable bio-based fluid.

Why don’t more utilities use biodegradable bio-based fluid?

A growing number of utilities are taking advantage of the superior environmental profile and performance-enhancing characteristics of biodegradable bio-based fluid. But others are reluctant to make the switch based on misunderstanding and misguided concerns over cost and effectiveness. Also, we believe that some utilities are just not willing to make the commitment to a sustainable green technology solution.