Beginning in 2008, Xcel Energy (Minneapolis, Minnesota, U.S.) will use renewable soy-oil-based dielectric coolant in all new single-phase transformers throughout its eight-state territory that is comprised of 3.3 million customers. Petroleum-based oils will be replaced using Cooper Power System's Envirotemp FR3 fluid — a biodegradable, biobased dielectric coolant.

Xcel's customers had been asking the utility to change the way it makes and delivers energy. “We're listening and we're dedicated to really minimizing our impact on the environment,” explains Mike Paradise, the director of strategic supply chain sourcing for Xcel. “These [soy-based] transformers are a really strong indicator of doing that and being a leader and an environmental steward.”

To date, Xcel is the largest investor-owned utility (IOU) to switch from petroleum to the FR3 fluid. “While we have many IOU customers, Xcel is just the second making a whole complete switch,” says Patrick McShane, global product manager - dielectric fluids for Cooper Power Systems (Waukesha, Wisconsin, U.S.). McShane notes that public power utilities such as Sacramento Municipal Utility District and Seattle City Light were very early adopters of the FR3 fluid and have also switched over. Other IOUs are indicating that they're going to make the switch as well.

The reasons why utilities are switching to FR3 fluid can vary, says McShane. The FR3 fluid is renewable, fire resistant, biodegradable and nontoxic to the environment, and it extends transformer insulation life. “For Xcel, it was a high-level decision to further their walking the talk on environmental stewardship,” McShane says. “This is another step in the right direction. And there's no question that the total life-cycle costs are a savings as well as an improvement for the environment, fire safety and sustainability.”

In addition to using FR3 fluid in its new transformers, Xcel expects to have more than 2500 MW of wind power on-line by the end of 2007.