Entergy Corp. and Cleco Corp. have transferred functional control of their transmission systems to Midcontinent Independent System Operator or MISO, the Carmel, Ind.-based regional transmission organization.

For Entergy, the transition took more than two years of planning and preparation by MISO, the Entergy utility operating companies, and numerous stakeholders. For Cleco, which provides power to customers in central Louisiana, the process took even longer, beginning in 2009.

MISO is one of the largest regional transmission organizations — an organization that manages the flow of power on the grid and operates markets for the purchase and sale of electricity.

The shift to MISO is expected to save Entergy’s customers an estimated $1.4 billion over the next decade, said Tom Reagan, Entergy’s vice president, RTO implementation

Entergy’s utility operating companies include Entergy Arkansas, Inc., Entergy Mississippi, Inc., Entergy Texas, Inc., Entergy Louisiana, LLC, Entergy Gulf States Louisiana, L.L.C., and Entergy New Orleans, Inc.