34.1c: "(c) Exemptions. (1) If an agency of the State in which the utility is organized and operating approves or authorizes, in writing, the issuance of securities prior to their issuance, the utility is exempt from the provisions of sections 19, 20 and 204 of the Federal Power Act and the regulations under this part, with respect to such securities. "
"34.1c.3: (3) For certain qualifying facilities. Any cogeneration or small power production facility which is exempt from sections 19, 20 and 204 of the Federal Power Act pursuant to Sec. 292.601 of this chapter shall be exempt from the provisions of this part. "
These are the only reasons for exemptions I can find.
Whichever was used, there is no fault in following regulations.
Enron received a blanket waiver from all of part 34, you're looking at regular exemptions.