Power markets are tougher than most because they have crazy unforecast volatility spikes that dwarf what you'd see in equities or other commodities. Imagine if the price of gold or AAPL traded in a range of $40-60 for months and then one day traded at $2,200. That's PJM power during the polar vortex. It's a balancing act, and if you want to guarantee the clearing firm never takes a hit you end up with margins so high that no-one can afford to enter the market which itself drives up societal prices potentially far more than an occasional on-time hit.
That said, power markets are insanely complicated and the people running them often have far fewer resources than the people who could exploit them, so it's more common to find edges that are effectively manipulating a poorly written rule or procedure than in equity or listed commodity markets, both imo and as the enforcement record shows.