BOSTON (AP) — State regulators have approved a 29 percent rate increase sought by Western Massachusetts Electric Co., which serves about 200,000 customers in Western Massachusetts.

WMECo has said the rate increase would take effect Jan. 1 and remain in effect for six months. It would raise the average residential customer's bill by about $26 a month.

The increase was approved Friday by the state Department of Public Utilities.

WMECo had sought it to offset its costs in competing for the natural gas it uses to generate electricity. Natural gas supplies have in tight supply in New England.

In September, Massachusetts regulators approved a 37 percent rate increase for National Grid's 1.3 million electric customers. That amounts to about $33 a month for that company's typical residential customer.