What do we mean by 'system capacity'?

System capacity refers to the maximum amount of power that a system can deliver at any given time. This concept is critical for ensuring that the electric power system can meet the demands placed on it without experiencing failures or outages. Understanding system capacity allows operators to predict how much power can be pushed through the grid during peak usage periods.

The relevance of this concept becomes even more pronounced when considering factors such as load forecasting and grid reliability. If the demand exceeds the system capacity, it may result in brownouts or blackouts. Therefore, operators must always be aware of their system's capacity to manage load effectively and maintain stability within the electrical grid.

The other options do not accurately encapsulate the essence of system capacity. For instance, the minimum amount of power refers to operational needs rather than capacity limits. The total cost of running the electric system is an entirely different metric related to financial aspects, and average power consumption over a year does not reflect the instantaneous capability of the system to deliver power.