State-owned utility Santee Cooper will shut down four coal-fired units at two power generating stations on Dec. 31.

The utility’s announcement today, which follows the board’s approval in October without specifying closing dates, affects two units at Grainger Generating Station in Conway and two of the four units at Jefferies Generating Station in Moncks Corner.

The other two Jefferies units are little-used, oil-fired and will eventually be shut down. No date has been announced.In a statement, Santee Cooper said the decision was in response to changing generation needs and expensive new environmental regulations that would require significant upgrades at those stations. They are Santee Cooper’s oldest and smallest generating stations.

The Jefferies hydroelectric units will not be impacted.

Santee Cooper is relocating affected Jefferies employees to other positions made available through attrition, so no layoffs are anticipated. Grainger has been idle since the spring, and most employees have already been relocated from that station.

Read more in upcoming editions of The Post and Courier.