Environmental Impact of Transformer Leaks and Spills

It is estimated that billions of gallons of mineral oil are in use in U.S. electric systems today. Each year, roughly 6,000 transformer spills are reported. That adds up to approximately 250,000 gallons of transformer fluid spilled on an annual basis. With our aging infrastructure, transformers are failing at a faster rate, spilling roughly 15,000 gallons more oil each year.

The environmental risks associated with leaks and spills of conventional petroleum-based mineral oil transformer fluid are cause for increasing concern as the average age of transformers increases. In many cases, clean-up and remediation of petroleum-based mineral oil can be very expensive and time-consuming, not to mention the prolonged nightmare if lakes, rivers, or groundwater supplies are contaminated. Hence, there are stringent environmental regulations and liability risks involving petroleum-based mineral oil leaks and spills.

As a response, utilities have been forced to develop extensive, expensive contingency plans and detailed procedures to handle accidental spills and leaks of petroleum-based mineral oil transformer fluid. These elaborate procedures require personnel training and purchasing special equipment. This is particularly true for utilities in environmentally sensitive areas where they have to worry about long-term threats to marine life from spills or leaks from transformers located near the water.

Costly consequences.

Even a relatively small volume of transformer oil can cause a large headache. A municipal electric utility in Iowa had to clean up a 20-gallon spill of a PCB-contaminated transformer oil. The spill remediation alone cost the utility more than $20,000. Click here for more information.

On a much larger scale, a transformer failure at a Tennessee utility substation caused several thousand gallons of mineral oil to spill inside the facility. Approximately 2,000 gallons of oil were captured by the oil-spill containment pond, but another 13,000 gallons of oil seeped into the fractured limestone beneath the transformer. Utility workers and contractors recovered the accessible oil and removed the contaminated soil according to Environmental Protection Agency (EPA) guidelines. As a result of this event, the utility was required to invest in larger, more effective containment bays around its major power transformers in order to control fluid leaks and prevent similar mishaps in the future. (2000 TVA Annual Report.)

This growing environmental problem is exacerbated by our nation’s aging, over-taxed utility infrastructure. While any transformer can fail, aging transformers pose a particular risk due to degradation of their insulation material over time. We can only expect the frequency of transformer failure to increase along with increasing environmental consequences, unless we take action now.

Biodegradable bio-based dielectric fluid is the answer. A growing number of utilities are taking advantage of its superior environmental profile and performance-enhancing characteristics. But others are reluctant to make the switch based on misunderstanding and misguided concerns over cost and effectiveness.