Profit margins are set by the state utility control board. The board says 11% profit Max, so that is what all of the major utilities make. The challenge is that with a fixed profit percent, they have a heavy incentive to maximize open. You can spend $10 and make $1.1 or spend $100 and make $11.
It's a very problem to the healthcare market. Health insurance also has fixed profit, therefore there is a huge incentive to drive up costs. Better to make 15% on a $10,000 drug then 15% on a $10 one.