Thank's alot for the useful answers. Indeed I was thinking about a centralized fixed value "gift voucher" kind system which could be bounded to - let's say - 1 Euro per coin. Still I don't understand if for this scenario all coins would need to be calculated by the central instance and the users (who perform transactions) would not need to mine any more?

Thanks for the reply. Anybody has an answer to my question?

Please excuse my confusion, I have a question regarding the usage of Bitcoin's approach for an alternative chain ( https://en.bitcoin.it/wiki/Alternative_Chains ).

Would it be possible to create an alternative chain where all coins are pre-calculated from the beginning on so that no mining is possible? The system should be used to secure transactions only. I guess this question is related to the question "what happens when all 21 million Bitcoins are mined?".

Thanks for your advice.