Mississippi Power says it now expects its Kemper County Energy Center to be in service by the end of May 2017. The company has moved back the planned date several times as it deals with operational issues at the over-budget integrated gasification combined cycle (IGCC) plant.

The utility says the latest delay is primarily related to repairs and adjustments associated with a particulate control device as well as the plant's sour water and ash removal systems.

Kemper County IGCCIt says the new schedule reflects the expected time needed to restart both gasifiers and associated equipment, and to achieve integrated operation of all plant systems to sustain electricity production from syngas.

The IGCC process starts by turning coal into synthesis gas, a combination of hydrogen and carbon monoxide. The syngas can then be cleaned of impurities, and burned to drive a turbine. Excess heat goes to power steam turbine.

Kemper is years behind schedule and billions of dollars over the $2.2-billion cost estimate given in 2010 when construction began. Read "Kemper County and the Perils of Clean Coal Technology.")

Mississippi Power says the Kemper plant achieved integrated operation of both gasifiers earlier this year and is producing sulfuric acid and ammonia as well as capturing, transferring, and storing carbon dioxide.

The company says its March report to the Mississippi Public Service Commission contains an increase in the cost estimate subject to the cost cap for the Kemper IGCC of approximately $38 million.

These costs include an adjustment of approximately $22 million related to the schedule adjustment, $8 million related to start-up fuel and $8 million primarily related to the current outage repair. These costs will be paid by its parent, Southern Company, and Mississippi Power.