tankage

/T AE1 NG K IH0 JH/
noun
  1. 1

    Storage in a tank.

  2. 2

    The amount that a tank (or tanks) can hold.

  3. 3

    The charge levied for storage in a tank.

  4. 4

    Waste matter from tanks, especially the dried nitrogenous residue from tanks in which fat has been rendered, used as a fertilizer.

Source: https://en.wiktionary.org/wiki/tankage