Ellington

HATTIESBURG, Miss. (AP) — South Mississippi Electric Power Association plans to join a regional power transmission organization at the same time as Entergy Corp. utilities.

Hattiesburg-based SMEPA, which generates and wholesales power to 11 electric cooperatives serving 410,000 Mississippi customers, says it will join Indiana-based MISO in December 2013.

MISO, the Midwest Independent Transmission System Operator, now directs electricity transmission in parts of 11 Midwestern states and Canada's Manitoba province. The nonprofit group tries to route the cheapest possible electricity to users, even if it's generated at a faraway plant instead of a nearby one.

Like Entergy, SMEPA says joining will save customers money, from $4 million to $40 million a year according to studies.

New Orleans-based Entergy won approval this year for its utilities in Mississippi, Louisiana, Arkansas and Texas to join MISO.