This integration can import a CSV into the long term statistics, if you can convert your data in the required format.
But you would need to filter/merge the rows to be hourly, not quarterly; also I think it expects an increasing value, not partial sums.
Apparently it uses the undocumented function async_add_external_statistics, if you want to create an integration to import directly from the website without having to download and convert the file manually each time.
I also have e-Distribuzione, but right now I am unable to register to the website and check the source CSV myself.
Can you provide a few rows sample of the original data?