The Electric Reliability Council of Texas (ERCOT) has many roles and responsibilities. But, ultimately, it has one purpose that stands above all else: balancing the supply of electricity with demand. This is called the ‘Power Balance’.
And, when ERCOT’s Security Constrained Economic Dispatch (SCED) can’t - or won’t - call upon enough generation to meet demand, we say it is “violating the Power Balance constraint”.
When this happens, the Power Balance Penalty Curve comes into play. But how does it work?
When might ERCOT choose to “violate the Power Balance constraint”?
Sometimes, there will be significant sudden changes in generation and/or load.
When this happens, ERCOT’s Security Constrained Economic Dispatch (SCED) might not have enough generation available in the next five-minute operating interval to meet all of the demand on the system.
Alternatively, SCED may have enough generation available to meet all of the demand on the system. However, it may decide that the cost of doing so is too high (relative to the cost of not doing so), and decide to meet all of that demand.