The Kemper County Energy Facility will not reach full operation by its latest mid-March deadline, project owner Southern Company subsidiary, Mississippi Power announced March 16 in a filing with the U.S. Securities and Exchange Commission (SEC).

“On March 9, 2017, Mississippi Power experienced certain tube leaks in one of the syngas coolers for gasifier ‘A’ and commenced an outage on gasifier ‘A’ to perform necessary corrective actions. As a result, Mississippi Power no longer expects the remainder of the Kemper IGCC will be placed in service by mid-March 2017,” the filing says.

The Kemper County Energy Facility, a new-build, integrated coal gasification combined cycle plant located near Meridian, Mississippi, is currently three years behind schedule and $4.7 billion over budget. Once completed, the plant will employ two gasifiers and a carbon capture system to burn low-rank Mississippi lignite with emissions roughly equal to those of a natural gas plant.

As of the company’s last monthly SEC filing, the plant was expected to reach full operation by mid-March, following several delays over the course of the last few months. All that remained to be done was to complete startup activities on the gasifiers, according to that filing.

“During start-up activities associated with Gasifier A, tube leaks were identified in the syngas cooler. Work is beginning to address these issues and complete associated repairs,” Southern Company spokesman Jeff Shepard told POWER. “The syngas cooler, as its name suggests, cools the syngas after it has been produced by the gasifier and just before it is sent to the plant’s gas cleanup system. The captured heat is then used to make steam to help power the plant’s steam turbine.”

Shepard declined to expand on the cause of the leaks, or if such leaks could occur in the plant’s other gasifier.

As a result of this latest delay, Mississippi Power expects to increase the project’s estimated price tag an additional $25 million to $35 million per month, “which includes maintaining necessary levels of start-up labor, materials, and fuel, as well as operational resources required to execute start-up activities. However, additional costs may be required for remediation of any further equipment and/or design issues identified,” the filing says.

An updated timeline for the project has not been determined yet, but could be announced in the company’s next monthly SEC filing, expected in early April.

Abby L. Harvey is a POWER reporter.