During that time, Edwardsport, in rural Knox County, Indiana, occasionally experienced “negative generation” periods when the plant consumed more power than it produced. Critics pounced on these episodes, restating their often-made case that the nation’s newest IGCC plant never should have been built in the first place.

Fighting back, the utility, a subsidiary of Charlotte, North Carolina-based Duke Energy Corp., one of the largest utilities in the U.S., repeatedly has said it will take some time to get the extremely complicated plant running smoothly. Edwardsport is needed, Duke said, to provide a cleaner, reliable source of generation to shore up reliability in the face of many older coal unit retirements in the Midwest.

In recent months, Edwardsport has recorded some of its highest capacity factors — a measure of its generation output — in the past two years. In June, for instance, the plant generated 307,236 megawatt-hours of electricity, a capacity factor of 69% of the approximately 460,000 MWh it is capable of producing.

Edwardsport burns steam coal produced by Peabody Energy Corp.’s Bear Run surface mine in nearby Sullivan County, Indiana. Bear Run, the largest surface mine east of the Mississippi River, produces about 8 million tons of coal annually.

Jack Stultz, general manager III, regulated fossil stations, for Duke Energy Business Services, told the Indiana Utility Regulatory Commission that Edwardsport’s coal handling system “performed as expected,” receiving truck and train deliveries. Earlier this year, the plant had an estimated 386,000 tons of coal in inventory.

“Future coal deliveries will be by train from Peabody’s Bear Run mine and will be planned to match planned coal usage at the plant,” he said.

Since an outage at the plant last fall, Stultz said, Edwardsport “appears to have resolved the vast majority of its heat trace and insulation deficiencies, operating throughout much of the coldest winter months with only two incidents of frozen transmitters, neither of which required any significant downtime to resolve.”

The plant’s gasification availability decreased last December to 29.34%, he said, due to issues with the slurry charge pump on unit 2 and air separation unit. A slag buildup last December took about seven days to resolve.

“Setting aside the issues with the slurry charge pumps and air separation units,” Stultz concluded. “I have been very pleased with Edwardsport’s operations. My team and I are focused now on reliability of the station — we know we have a plant that will run — our intent is to get to the point of consistently being able to put it on and keep it on.”