In the '60's the Utilities carried "15% spinning reserve", where system load always had another 15% capacity sitting there ready to plough in. SCE now has maybe 5%, PG&E 10% for sure. The shortages come from penny-pinching by private utilities optimizing profit, cutting VERY close to the bone. Public/Government utilities like SMUD, BPA, Bureau of Reclamation, etc. don't have a mandate to maximize profit extraction, just a continuity of service mandate. If money goes back into the process, the power supply and service continuity get better. There is NO REASON to publicly support a thick layer of private capitalists that aren't adding product value, just extracting "surplus" money.
My friend was quoted $20,000 to underground a 100' stretch of powerline on her local property by PG&E. In Sacramento, for a virtually identical job, SMUD merely considers it a service they provide for free to ratepayers. SMUD didn't have to extort money to feed a rapacious Private Board of Directors. Utility base rates in SMUD territory are under 1/2 of what I routinely pay.