exhaustless

Unable to be exhausted; having an endless supply; inexhaustible.

Nectar ran / In courteous fountains to all cups outreach'd; / And plunder'd vines, teeming exhaustless, pleach'd / New growth about each shell and pendent lyre; [...]

The exhaustless conjecturings of that evening's full conversation, made such of the small party, as had hitherto been strangers, well acquainted with each other's turn of mind; […]

Not producing exhaust.

Near-synonym: nonpolluting

These obstacles preclude near-future solutions for exhaustless vehicles, or those having an exhaust with greatly reduced toxicity.