Everything here is oversized, and everything about the project has been controversial. Proponents argued that the facility would offer affordable electricity while producing a dramatically lower volume of greenhouse gases than conventional power plants. Critics contended that it relied on unproven, even unworkable, technologies and that construction was grossly mismanaged. The plant’s initial purpose was to convert locally available low-grade lignite coal into natural gas and, in turn, into electricity. After the original $2.4 billion price tag ballooned to almost $7 billion amid lingering technical problems, Mississippi Power and its parent Southern Company declared the gasification process a failure, and the facility now burns only piped-in natural gas. The sprawling complex, much of it now dormant, includes towering discharge stacks, giant gasifiers (each weighing more than a million pounds), some 170 miles of piping, elaborate capture facilities for carbon and sulfur dioxide, and batteries of gas turbines, as well as a dome capable of storing 100,000 tons of lignite and a 500-million-gallon reservoir.