The utility also agreed to reimburse the environmental groups for $2 million in legal costs and contribute $10 million to other groups for energy-efficiency advocacy and land conservation efforts.
"Overall, that is a large step forward for Arkansas and that's something we can certainly show at the end of our litigation," Gutter said.
McCloud said the company wasn't concerned there would be protesters when the plant formally joined the grid and noted that the April 13 event has been publicly announced.
"We settled with all the opponents," McCloud said.
SWEPCO, a unit of Columbus, Ohio-based American Electric Power, owns 73 percent of the plant. Other regional utilities in Arkansas, Oklahoma and Texas own minority shares.
The Turk plant sits on 3,000 acres between Fulton and McNab, Ark., and is using low-sulfur coal from the Powder River Basin in Wyoming.
SWEPCO, which serves 524,000 customers in Arkansas, Louisiana and Texas, says it is taking a balanced approach in fuel sources for its plants, using natural gas and coal.
Connect with Chuck Bartels on Twitter at www.twitter.com/cbartelsLIT