Many Northeast Wyoming homeowners received a surprise in the mail earlier this month.
Montana–Dakota Utilities, which serves areas like Sheridan, Buffalo, and Dayton recently raised the electric rates.
Homeowners found out February 4th that on average, they will pay almost $4 more per month and more than $44 more per year.
MDU says the increase comes from its purchase power agreements with suppliers.
Much of MDU's electrical power comes from its own coal plant, but the rest comes from contracted suppliers.
Since those suppliers increased their rates, the power company says it must do the same.