The one-line input textfield isn't exactly optimal for holding a 30+ line template. I wonder what's the HASS philosophy for stuff like this. In the nordpool plugin I used to put everything in configuration.yaml, which is convenient to store in version control and it's clear where the data is.
There should be support for a configuration in yaml. The template for the configuration should look something like this:
sensor:
- platform: entsoe
api_key: <YOUR API KEY>
area: "NL"
additional_costs: "{{0.0|float}}" #default value
Quoting @jpulakka:
There should be support for a configuration in yaml. The template for the configuration should look something like this: