It's pretty common for natural gas electric plants to use Brayton cycle turbines, which is the same thermodynamic cycle that the turbojet engines on airplanes use. But you can optimize the designs on the ground for efficiency (and zero thrust) instead of thrust-to-weight.
It's also common to use "combined cycle" technology which mashes the Brayton cycle engine together with an older-style steam loop for extra efficiency.
After reading the article, I think they're just saying they installed some miniaturized natural gas plants. I don't think they're literally running aircraft engines on the ground.