AARP has asked to intervene in a pending electric rate case before the Public Service Commission.
MDU is asking for a 12.3 percent overall rate increase. That amounts to about $25.4 million.
AARP Advocacy Director Janelle Moos said this proposed rate increase unfairly impacts residential customers.
"It's a 17 percent increase for residential customers," Moos said. "There's only an eight percent increase for commercial customers."
For a residential customer, the average increase would be about $14.94 per month.
Moos said AARP believes the residential customers should not bear the burden of this kind of an increase.
"It's a double increase, compared to commercial customers," Moos said.
Moos said this will hit customers 50 and older particularly hard.
MDU said the increase is due to investments made since 2017, including an 88 megawatt simple cycle combustion turbine at the Heskett Station north of Mandan. The utility said current prices do not reflect the cost of providing the electric service.
Under state law, MDU is entitled to an interim increase. The PSC granted a 6.6 percent rate increase, or $11.4 million. For an average residential customer, the monthly increase is $5.33 per month.
The interim increase is subject to refund, if the PSC's final order is less than 6.6 percent.
MDU was last granted an electric rate increase in 2017. That increase was 3.7 percent.
