Well, you have a pretty good price there, I currently have 0.21 Euro per Kwh day and 0.18 night (which I think is about the cheapest you canget, and free, offer is not active anymore, sorry).
This site is Dutch but you can put in your annual usages and stuff and it will show you the cheapest opstion: http://www.gaslicht.com/energie-vergelijken
I advise you to just look at that site again every year, becouse deals like 21 cents are most of the time only for one year, and choose the option which is then the cheapest.
I hope that helped you, if you have any question, feel free to ask me. (But keep in mind I am not any sort of electrician )
I can understand as long as I know the context, the problem is still speaking
From there, it seems now the difference for my current provider is only .00xx, so not really worth the hassle in switching.
Dank u wel!