KANSAS CITY, Mo. (AP) — Kansas City Power & Light Co. is seeking a 15.8 percent increase for about half of its Missouri customers.

The utility said Thursday that it needs the increased revenue to pay for environmental upgrades at its coal-fired plant in La Cygne, Kansas.

KCP&L officials say the $121 million annual rate increase would cost the average residential customer about $14 more a month.

The company said the federally required installation of scrubbers at the La Cygne plant cost $1.21 billion.

The Kansas City Star reports if the current request is approved, the affected KCP&L customers will be paying more than 50 percent more for power than they did a few years ago.

The rate increase for La Cygne would probably not go into effect until September 2015.