adequacy

(electricity) The existence of sufficient facilities within an electric power system to satisfy the customer load requirement under static system conditions.

noun

An adequate quantity: enough, sufficiency. See excess/insufficiency/enough.

Definition: ability, competency in some way (action)
Antonyms: inadequacy, inadequateness, insufficiency

(DOD) Operation plan review criterion. The determination as to whether the scope and concept of a planned operation are sufficient to accomplish the task assigned. See also acceptability; feasibility.

The noun has 2 meanings:

Meaning #1: the quality of being able to meet a need satisfactorily: "he questioned the adequacy of the usual sentimental interpretation of the Golden Rule"
  Synonym: adequateness
  Antonym: inadequacy (meaning #3)

Meaning #2: the quality of being sufficient for the end in view
  Synonym: sufficiency
  Antonym: inadequacy (meaning #1)