Option 1

If the issue the league has is not having enough powerplays in a game then the solution for a new penalty is simple. The newly implemented penalty will be called "failing to score on a powerplay" and just like it sounds, the penalty will be inflicted on any team who fails to score a goal on a powerplay opportunity. This means that any time a penalty is called for a different reason, there'll be nothing but powerplays and 4 on 4s until a goal is scored. This will drastically increase the excitement of the game and also cause teams who draw penalties to have something to look forward to. If refs are tilting the table one way or the other, simply kill off a penalty to create your own powerplay opportunity. Of course this will significantly change the structure of the game but if the league wants more powerplays to occur each game then this is definitely one of the best ways to increase the ammount.