I don't know much on racing in Germany - I do know that the following tracks in the Netherlands and Belgium are 'closest' to to you:
1.
MAC Vlijmen (51.688075,5.178111 on Google Maps) - It's the track I usually drive - it's clay, it's got a nice flow to it and it's relatively forgiving if you make a mistake. In the winter we drive indoors in a horse riding school in a nearby town, Rosmalen.
2. Indoor track in Uden - it doesn't exist yet but I think they start building in January (51.666593,5.616747 on Google Maps shows where the village is).
3.
ORRA Arendonk (51.311784,5.047632 on Google Maps) - I only drove on this track once, but it was a huge load of fun (though I still find it a scary track to drive on in the dry).
All of these venues are 120-160km away, and I know it's likely there are tracks nearer to Essen. However, if you fancy joining in on some club races or the Belgian-Dutch championship, I can guarantee you it will be worth the drive - (in travel time) for me the closest track is MAC Vlijmen, which is 120km/2 1/2 hours of travelling (by public transport)
