Until this thread, I have never encountered the term "bar tariff" for a list of drink prices, or "energy tariff" instead of rate. Those uses are simply not American English, and you would be misunderstood.
Hetzner is a German company so I find myself wondering if this is a British usage, or a mistranslation of the German word "tarif" that should be "rate"? (A common mistranslation category known as "false friends".)
21 occurrences of "tariff" on one of British Gas' pages: https://www.britishgas.co.uk/energy/guides/off-peak-electric... ("Your energy provider may offer time of use tariffs and cheaper night-time electricity rates.")
Is there any further distinction between a "tariff" and a "rate" in British English? The example sentence you provide uses both, which makes me wonder if there's even more to the picture here.
An EV electricity tariff might have a cheap night rate, and a more expensive day rate. Another tariff might be entirely variable rate (price changes every hour).
Wiktionary defines a tariff as "A schedule of rates, fees or prices." so I think my feeling is correct.