The Kansas Corporation Commission has formally approved Westar Energy’s rate increase request, signing off on a $30.7 million settlement reached in September.

Regulators announced the unanimous approval of the settlement Thursday. The deal was brokered by Westar, KCC staff and the Citizens’ Utility Ratepayer Board. The increases in electric utility bills will take effect Dec. 1.

Westar applied for the rate increase mostly to pay for required environmental upgrades at its La Cygne power plant in eastern Kansas.

Under terms of the settlement, residential customers will get the biggest increase, $18 million, followed by small businesses with a $12.7 million increase.

Westar is the largest utility company in Kansas with nearly 700,000 customers and 7,200 megawatts of electricity generating capacity.