* Cleco move follows Entergy into Midwest ISO * Move could be another loss to SPP power grid * Cleco hopes to integrate into MISO by Jan. 2014 By Scott DiSavino Dec 7 (Reuters) - Louisiana power company Cleco Corp on Friday said it filed with Louisiana utility regulators to join the group that operates much of the power grid in the U.S. Midwest. Cleco's decision to join the Midwest Independent Transmission System Operator (MISO), follows a move by its much bigger neighbor Entergy Corp in April 2011 to integrate its transmission systems in Louisiana, Arkansas, Mississippi and Texas into the Midwest power grid. Entergy, which in December 2011 agreed to sell its transmission systems to Michigan-based power transmission company ITC Holdings Corp for $1.78 billion, hopes to fully join MISO and complete the sale of its transmission system to ITC by the end of 2013. MISO operates the power system in 11 U.S. Midwest states and the province of Manitoba in Canada. Cleco said in a release that MISO has a developed power market that will produce benefits for its customers through increased reliability and more efficient dispatch of generation. "As our market structure changes, Cleco is positioned well to participate in MISO, known for the value it creates for its members and their customers through strict market oversight," Bruce Williamson, president and CEO of Cleco, said in the release. "Cleco's fleet is environmentally sound, well maintained and should perform well under MISO's operating guidelines," Williamson said. Entergy also said its integration into MISO would help customers, resulting in projected savings of $1.4 billion in the first decade. Cleco did not disclose the value of the benefits it hopes to achieve by joining MISO. MISO started overseeing the Entergy power system on Dec. 1, 2012 as the company's independent coordinator of transmission, a spokesman for Entergy told Reuters Friday. SPP LOSES ANOTHER Before that, the Southwest Power Pool (SPP), a rival power grid operator that has fought Entergy's move to the MISO, had been Entergy's independent coordinator of transmission since 2006, the Entergy spokesman said. SPP operates the power grid in several states including, Oklahoma, Texas, New Mexico, Kansas, Nebraska, Arkansas, Louisiana and Missouri. Cleco spokeswoman Robbyn Cooper told Reuters that Cleco is a non-transmission member of SPP. She said Cleco administers its own transmission system and SPP is the company's reliability coordinator. Officials at SPP were not immediately available for comment. In the press release, Cleco said if it is successful in joining the MISO, Cleco will retain ownership of its transmission and generation assets, and the MISO will take over the operation of Cleco's transmission assets and dispatch of its generation. Cleco said it hopes to integrate into the MISO in January 2014. Entergy hopes to integrate into the MISO on Dec. 19, 2013. Cleco serves about 281,000 customers in Louisiana and owns about 2,500 megawatts (MW) of generation. Entergy serves about 2.8 million customers in Arkansas, Louisiana, Mississippi and Texas and owns about 30,000 MW of generation.