N-Minus-One Contingency Planning

Grids are planned to survive the loss of any single element; firm capacity and redundancy are how that standard is met.

Surviving one failure

The N-1 criterion requires that a grid keep operating after the loss of any single major element, a generator, a line, or a transformer. Planners ensure enough spare firm capacity and network paths remain so that one failure does not cascade into a blackout. This drives reserve requirements and the value of redundancy.

A firm resource contributes to N-1 by being available to cover the loss of another element. But the resource itself is also an element that can fail, so its own outage must be survivable. This dual role is why fleet redundancy matters for the burner (MetroVolt).

Redundancy over a single unit

Because a single MetroVolt unit has a design-stage availability of 0.86 to 0.995, planning around a single unit would violate N-1 for a critical load. A redundant set of units, or a unit plus grid tie and storage, satisfies the criterion: the loss of any one is covered by the others.

Honest framing

N-1 planning is standard grid practice and applies to any generator. For MetroVolt it is a reason the design leans on modular, redundant fleets rather than single large units, which also aligns with the availability gate.