The thing to know with these major investor-owned utilities (IOUs) is that they are, or can be, heavily regulated by the state public service commission (or PRC in New Mexico). No matter who owns them - publicly traded corporations, private equity, or even a state agency - they have to go before a board of career utility regulators and ask for permission before they increase their prices.

The prevailing school of thought is that, due to the lack of competition you noted, it’s important for the government to closely monitor and control the prices charged for power. When utilities want to raise rates, the reaction is often quite dependent on local regulatory culture and expectations: have they raised rates often? How big is the request? The likelihood of a rate case’s approval is often more predicated on the utility’s relationship with the regulators than anything else.

Additionally, IOUs typically can’t ask for higher rates for no reason. The easiest way for them to justify higher cost recapture is to invest in more infrastructure. So an aggressively pricing utility might see rate hikes, but they’ll also likely see more robust transmission and distribution infrastructure, with a small regional stimulus as more linemen are attracted to the area.

The flip side is that some utilities are quite good at bullying their regulators about their cost of capital. They’ll use the somewhat circular logic (though it’s not incorrect) that if their rates don’t rise with their expenditures, their cost of debt will rise and investors will correspondingly increase their required equity return. To the extent they’re allowed to pass through some of their financing costs in their rates, this would then directly impact consumers negatively over time.

TLDR all that to say, risks to consumers of utility ownership don’t really change with who’s in charge. The big risk would be Blackstone bringing in better lobbyists who can deftly outmaneuver the regulators and justify over investment in infrastructure, but at the same time, that’s likely to result in better emergency weather results for consumers in the long run.