Oconto Falls Municipal Utilities will replace its outdated electric distribution system with modern facilities that have three time its present capacity.
“It’s aging and is ready to be replaced,” Beth Rank, interim manager, said April 9.
The Public Service Commission approved the project the same day.
Utilities have been replacing their old 4 kilovolt distribution systems with 12.4 kV systems to keep up with increased customer demand for electricity as they adopt advanced technology dependent on reliable electrical power.
OFMU’s existing electrical distribution system is old enough that Rank couldn’t immediately say how long it’s been in service. It’s referred to as a “legacy” system in documents submitted to the PSC.
The changeover to a higher capacity began with building two new substations beginning in 2024 to replace two older substations, rated for 4.6 kV service, and were approaching the end of their useful life.
The new substation went into service at the end of 2025, according to Forster Electric Engineering, the city’s electrical consulting firm.
The $6.4 million substation project was a main driver behind the 22.5% rate increase the PSC authorized last fall and OFMU implemented in December, Rank said.
“That was the biggest project we’ve had, before that there weren’t many projects,” she said.
Forster’s report to the PSC stated that the upgrade project could require a 7% increase in revenue or about an $8 increase in monthly residential electric bills currently at $78.
However, Rank said the 12.4 kV upgrade won’t require a rate increase as the new transformers have been acquired and most of the labor will be done in-house.
The entire OFMU distribution system will be upgraded to 12.4 kV mainly by changing out the dozens of old transformers with ones that have the higher capacity. Power lines to each address won’t be changed.
The process could interrupt power for one or two hours, according to Forster.
Work is scheduled to begin this summer, and the utility will call each customer and inform them when their power will be interrupted.
The changeover is expected to take about three years to complete, according to Forster.
The utility buys power from WPPI, which is distributed over WE Energy transmission lines. American Transmission Co.’s 138 kV line will be OFMU’s new electrical connection and should be more reliable, Rank said.
