(I'll just do it in English for you)
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-vergelijkenI 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
)