Topeka ? Westar Energy has agreed to delay a request for a rate increase related to coal plant upgrades as part of an agreement approved by a state commission.

The Kansas Corporation Commission on Tuesday approved a plan that would allow Westar to receive about $3.5 million in revenue related to costs that have not been recovered for improvements at the La Cygne power plant, The Topeka Capital-Journal reported.

Westar also agreed not to ask for a rate increase until March. That means about two-thirds of the company’s customers who are expected to see an increase of about 16 cents on their bills will not pay more until October 2015.

Westar Energy and Kansas City Power & Light own the plant together and need to make upgrades to comply with federal emissions rules for coal-fired plants. The plant is expected to be back online by June.

Kansas City Power & Light will file its rate case in January and work on the basis of estimated costs until then. If the plant’s operational costs do not match their estimate, the company will either collect more from customers or issue a refund.

In 2011, the Kansas Corporation Commission ruled that the utilities could recover a combined $1.2 billion over multiple years to cover the cost of the plant’s upgrades. Those costs do not cover the costs of running the plant.

The utilities had argued they would be harmed if they could not start recovering the costs by increasing rates until their next general rate case before the state commission.