It's the way the system operates. The market operator calls for bids from generators to fulfill forecast demand plus an extra amount to cover generation-transmission failures that might occur. Because the market operator has also introduced a cumulative price cap some generators don't enter the auction because the capped amount doesn't cover their costs. Then the market operator pays some big users to not use electricity. They also issue a lack of forecast reserve notice. Next step is to direct generators to fire up. A generator under direction is compensated. If that generator had bid at the capped price they would have lost money.
Usually it's the spot price that signals generators to either fire up or shut down. In these circumstances there is a component of direct action from the market operator to match supply with demand.
