The ability to respond to system changes and uncertainties.
System Flexibility
System flexibility is defined as the ability of supply-side and demand-side resources to respond to system changes and uncertainties. Flexibility also includes the ability to store energy for delivery in the future and the operational flexibility to schedule/dispatch resources in the most efficient manner.
Flexibility Reserve by NYISO
Flexibility reserves are an emerging concept for addressing variability and uncertainty on longer timescales than operating reserves and regulation service. The Ancillary Services Market secures flexibility services from suppliers to maintain balance in response to changing conditions on the electrical grid.