Tarif/Tarife means price list of anything. Your barber, restaurant, taxi service, hospital can have one. tariff as in the meaning of custom tax is a very narrow meaning considering the usage of the word in general (but that's OK).

Import duty is "gümrük vergisi", and the general list of this is "gümrük vergisi tarifesi" in broad sense. It also has a more technical name here but both I don't remember it, and it doesn't matter in this context.

In the Japan's context we would call it "elektrik fiyat tarifesi", or "elektrik tarifesi" for short, for example.

Cheers,

Your friendly Turkish HN user.