Yes, there are multiple competing providers - all the electricity comes from a single grid but competition in how you are billed for usage.

Many people choose a single fixed or variable rate tariff, but there are also off-peak tariffs that are very cheap at night but slightly more expensive in the day (designed for EV users), or even tariffs where the rate changes every 30 minutes depending on what is being generated - in this case when there is excess solar and wind generation then sometimes the rate even goes negative and you are paid to use the excess power.