That's my recollection, as well. In which case, many existing regulations, designed to address conventional generation and transmission issues, may have been wholly inappropriate to energy trading.
For example, perhaps, a generator couldn't make commitments that required construction of a new plant and issuing stock to finance the venture without being a DOE review of the market and the pricing/financing schedules. The electric utilities are closely regulated, remember.
But when a trading company sells electricity to a customer for future delivery, it's planning to buy that same electricity from another supplier. They're not in the business of generating electricity or building plants, they're in the business of "making a market" for existing generators.
Thus, stock issued in this context would not necessarily require prior approval by the DOE. A waiver would make perfectly good sense.