Yes this could help, but I don’t understand why I should use an extra add-on while the data is there right?
Again, this could help and I will certainly try it but I just want a way to get the already there data. With this add on I get the feeling it will save the data again. Or does this actually use the data that is already there?
The values in the energy dashboard graphs are calculated from the statistics database as they are needed for display. There are no entities created for daily/weekly/yearly stats.
So you have to either calculate these yourself using SQL sensors or keep track of them using utility meter helpers.