What killed Kemper?

Mississippi Power’s 582-MW Kemper integrated coal-gasification with carbon capture project is officially dead. The Southern Co. subsidiary and the Mississippi Public Service Commission staff at the end of November reached a settlement that will see the utility eat about $270 million in costs of the failed lignite gasification piece of the project.

Mississippi Power last summer abandoned the troubled coal gasification technology, and is running the plant as a conventional combined-cycle gas-fired generator. The full PSC must approve the settlement, expected in January.

The project has been a money-gobbling monster from its beginning in 2010, with the original cost estimate of $2.4 billion rising to $7.5 billion when Southern walked away from gasification last June.

The project in Kemper County was to have been a key to the Obama administration’s plans for dealing with carbon dioxide emissions from electric power plants, while providing a path for keeping coal in the generating equation. The Clean Power Plan, which the Trump administration is in the process of abandoning, would have encouraged projects such as Kemper.

What killed Kemper? It looks like a case of technological hubris on the part of the utility and the U.S. Department of Energy. The gasifier was a unique product, tried only at a small scale at DOE’s National Carbon Capture Center in Wilsonville, Alabama. The “transport integrated gasification” known as TRIG was an advanced approach to earlier, untried pressurized gasification technology. TRIG was a joint development by Southern, DOE, and KBR.

In choosing to make a bet on scale up of the TRIG technology, Southern passed up existing coal gasification technology with a long history. KBR had hopes that a success at Kemper would help its effort to market the gasifiers in China. Southern said the TRIG technology was particularly well suited to gasify low-rank lignite, plentiful in Kemper County.

Southern could have chosen to go with Lurgi gasification technology, developed by Germany in the 1930s, and used in South Africa’s Sasol plant that turned coal into gasoline during the apartheid regime. In the U.S., Basin Electric’s Dakota Gasification Co. has been gasifying North Dakota lignite since 1984 at its Great Plains Synfuels Plant, reliably providing synthetic natural gas to the Northern Border Pipeline and to a nearby Basin generating station for gas peaking units. The Dakota syngas project also captures and stores carbon dioxide.

Great Plains Synfuels Plant

Scaling up the TRIG technology at Kemper ran into many problems, costing Southern time and money. An article last February in IEEE Spectrum noted that “many of the original design specs needed changes….One design flaw miscalculated pipe thickness, length, quantity, and metallurgy. After these changes were made, additional changes needed to be done to support structures.”

Once the gasifiers were built, they had severe operating problems, including ash fusing to the gasifers’ walls, and problems with ash removal.

As the plant fell further behind schedule and costs rose, the advent of cheap natural gas from fracking undercut the economic assumptions behind the project. In 2010, Southern estimated that natural gas prices would be in double digits. Instead, they are less than half the utility’s estimates.

Had Southern decided to play it safe with Kemper and not push the technology to where it had not gone before, the project well might be working today.

— Kennedy Maize