JACKSON, Miss. (AP) — Entergy Corp. estimates its electrical customers in Arkansas, Louisiana, Mississippi and Texas saved more than $250 million during the first year of Entergy’s membership in a regional grid manager.

Customer savings are building more quickly than Entergy estimated before joining the Indiana-based Midcontinent Independent Transmission System Operator in late 2013. Entergy had estimated $1.4 billion in customer savings over a decade.

MISO directs electricity flows across parts of 15 states and the Canadian province of Manitoba. It seeks to make sure power is generated at the cheapest possible plant, even if it’s generated faraway instead of at a nearby plant owned by Entergy. It also manages investment in new transmission lines, to ensure smooth power flows.

New Orleans-based Entergy has 2.8 million customers in its four states.