I also notice they don't mention the noise profile of these plants. Putting a stationary engine like that will make an insane amount of noise, and even enclosed will change the soundscape for miles around, affecting everything from human well-being to animals' ability to communicate. Not cool.
But maybe they aren't really thinking about that because it is nowhere near being done.
Gas turbine power generation is already a thing. For example 20% of UK grid power right now comes from "combined cycle gas turbines" - which are a very efficient way to turn natural gas into electricity. They've solved the noise issue for those plants.
Um, noise mitigation is still an issue at existing gas plants (e.g., [0-3]) and often only partially dealt with by local regulations, and this group are claiming their engine is substantially different, supersonic vs subsonic, and crossing that threshold usually involves large noise generation effects.
But maybe they aren't really thinking about that because it is nowhere near being done.