The utility industry’s effort to wean itself off coal is slowly advancing.

South Carolina Electric & Gas announced this week it has shut down it Canadys Station for good, marking the end of more than 50 years of service for the Colleton County generator.

Meanwhile, Moncks Corner-based Santee Cooper said it’s started the two-year process of dismantling the equipment and administrative offices at its 49-year-old Grainger coal-fired plant in Conway.

Elsewhere, the Tennessee Valley Authority’s board voted Thursday to mothball six coal-powered units in Alabama and replace two others in Kentucky with a natural gas plant.

All cited increasingly stringent federal air regulations for the decisions.

Canadys Station near Walterboro is the latest to be shut down.

SCE&G previously announced that it would cease operations at the 51-year-old coal plant this year, It went offline for good on Nov. 6.

“The plant closing is part of SCE&G’s efforts to reduce emissions, achieve a more balanced generation portfolio and comply with new environmental regulations that will take effect after 2015,” the Cayce-based utility said.

One of the three generating units at Canadys was shut down in late 2012. SCE&G originally planned to convert the remaining two to natural gas before retiring them for good in 2017. It later decided to shut the entire station by the end of 2013 after reevaluating its needs and the economics of the move.

The decommissioning of Canadys is expected to several years and will involve demolishing the plant, closing all ash and wastewater ponds, and building an on-site dry ash storage facility.

SCE&G said it has no immediate plans to sell the land.

At Grainger, state-owned Santee Cooper said its plan is to clear the Horry County property, “with the idea that it could be reused for a new commercial venture.”

The two South Carolina utilities plan to replace their diminished coal-fired capacity with electricity from two units they are building at their jointly owned V.C. Summer Nuclear Station in the Midlands.