The Exelon plant on Summer Street in South Boston is a prominent feature in the South Boston skyline. Once upon a time, this plant was able to produce over 700 MW of natural gas power, but today all that remains is a distillate fired jet engine that puts out 12 MW. The story of this plant is a common one in New England. It was built in stages by Boston Edison and the two natural gas fired steam turbine units came online in 1965 and 1967. During deregulation in the 90s, it was sold off to a merchant generator called Sithe Energies which was subsequently acquired by Exelon.
The 2000s were not kind to this plant. In October of 2002, Unit 2 suffered a catastrophic fire which resulted in the unit being retired. In 2007, unfavorable economics led to the closure of Unit 1. The only active power generation equipment remaining at the site is a 12 MW distillate fired jet engine that fires during periods of extremely high demand in the ISO-NE grid. If you see emissions from the jet unit on a cold winter or a hot summer day, you know that power prices are off the charts since the economics of distillate require prices north of ~ $270/MWh. If you look at the aerial photograph of the site, you'll notice the large tanks used to hold the distillate fuel.
Although this plant is mostly dormant, I wouldn't write it off completely. Its in the NEMA zone which is capacity constrained, it has grid interconnection, a water source, and excellent proximity to load. I'd be willing to bet that Exelon is thinking about re-powering this unit as a modest combined cycle.