Peakers etc are privately owed thus come under the NEC if owned by a utility company then they are code exempt(parts used for generation of power only) remember we're into deregulation now.Besides Conduit fill. Temp. rating of conductors , tray fill , Clearances , etc etc would be code issues.
I'm sorry to be quarrelsome but the ownership is a non issue under the NEC. If it is a power generation facility it falls under the National Electrical Safety Code (NESC) rather than the National Electric Code (NEC) Any and all parts of a building the primary purpose of which is power generation is beyond the scope of the US NEC.
The law would not permit the application of the NEC to a facility owned by the Tom H wealth trust and not to the Dickerson peeking units owned by Potomac Energy. Potomac Energy is a deregulated power provider to and they could not afford to operate under the NEC.