which electricity supplie

You know that the word "current" can mean "electric current" or "at this time" in English, so if you want to ask which electricity supplier is the best in Spanish, then you need to change your post to:  "¿Hola, alguien sabe que proveedor de electricidad es el mejor?. Or "¿Hola, alguien sabe que proveedor de energía es el mejor? Google translate can be very risky sometimes! When you ask a question in Spanish, you should put an upside-down question mark at the beginning of the sentence and a normal one at the end.

Although Iberdrola is the main electricity supplier in the area, there are various options of who you pay your bill to. You could try here: https://electricityinspain.com/electricity-suppliers-in-spain/

We have Iberdrola now for 5 years. Checked other suppliers yearly but never changed.

We find the 8-hour tariff the cheapest and best fit.

Only cheaper if you can use a lot of electricity through the night.

Not necessarily: log what power you use and at what times & days for a period then see which is the best tariff for you.

Works for us! Everyone is different 

That's why we use the 8-hour tariff where you can choose 8 hrs/day with the highest consumption !

We are non-resident. Last winter we had 90% at low tariff, and previous summer 60% at low tariff.