Transformers fall into the category of necessary evil. How else to describe something which makes it possible for us to power our homes yet sometimes explodes, leaks, catches fire, and spills toxic chemicals?
This is not only the case for those transformers located overhead on a pole like mine, but also those pad-mounted and buried underground. In 2010, an underground transformer in NYC exploded, sending a 70-foot fireball into the air. A woman walking down the sidewalk in San Francisco was critically burned when a transformer exploded underneath her. A transformer beneath the medical district in Memphis exploded in 2012. Dozens of these incidents turn up with a simple search. Stories of overhead transformers causing fires, injuries, and environmental damage also abound.
One possible alternative to the present norm of mineral oil (or sometimes PCB) filled transformers is a vegetable oil-based transformer fluid. Usually made of soy or rapeseed oil, it is also known as natural ester insulating fluid, or natural ester dielectric fluid.
Compared to mineral oil, vegetable-based transformer oil is:
- less flammable
- less toxic
- less likely to degrade transformer components
- made from a renewable, domestically-produced resource
One of these taken alone would seem to be a valid argument in favor of retrofilling transformers with vegetable oil-based fluid. Taken together, they make a very strong case.
A case can be made that fossil fuels are used in the production of soybeans and rapeseed, and that is a valid, mitigating argument. However, because this is an issue of human, animal, and environmental health and safety issues, this cannot be analyzed solely on the basis of carbon accounting.
Based on what I have read, wider use of natural ester dielectric transformer fluid would be a boon overall, especially in applications with high fire and explosion danger issues and, closest to my heart, residential applications near edibles and child play/school areas.
I suggest we begin noticing the placement of transformers, not just in our own yards, but near schools and playgrounds, sports fields and recreational areas. Maybe it’s time to start letting our utility companies know we’d like them to take an interest in converting to vegetable-based transformer oil.