Thank you for your interest. You can apply to become a sperm donor in either Denmark, Hamburg or Amsterdam. It requires that you can show proof of residency and will be residing in one of these countries for at least 1,5 years after you’ve submitted your application. 

Please read more about how to become a sperm donor here: 

Denmark at www.blivsæddonor.dk 
Hamburg at www.werdesamenspender.de 
Amsterdam at www.europeanspermbank.com/donor-nl-nl