Buying advice Diesel or petrol

Hello together, I have read useful information here in the forum for years and decided today to make an account because I urgently need help. It is about buying a new vehicle. I will soon start an apprenticeship and the job is unfortunately a bit far away, so I would have to drive 50 km back and 50 km every day. In other words, it is 100 km daily and 500 km a week. About 20 km would be highway, and the rest is 20 km inland and 10 km rural road. Diesel problem I am very undecided which is exactly the right solution. Either I buy a petrol truck and have my rest despite the extra consumption, or, I buy a diesel truck and hope that I will not get any driving bans in the area. I think that this year there will be no bans anyway with the Euro 5, since you are certainly on the safe side until the end of 2019. My budget is between 6,000 and 8,000 euros. It could also be something more, then I would have to However, since I own a BMW 318i with 143 Facelift, it would be strange for me to buy a new car that has less power than my BMW. However, this one consumes between 9.2 and 9.4 liters inside. Have looked at the Astra/Corsa, or the Corsa E with 95hp diesel. But from a BMW to a small Opel would be a big step backwards for me what smooth running and processing was about… Which car would be in question, but which has enough power Now buy a diesel (Euro 5/6) with the problem that I no longer come to the city center? In theory, I would have time with the Euro5 until next year or the end of 2019 until the Euro 5 would certainly be banned. But this risk is clearly too great for me, and a big waste of money… What car would your recommendation be? Greetings EmanLF