If you try to use any coins as a curreency, you cannot limit the amount. Look at all these USD, GBP, EUR, etc. They generate money with unlimited means. The key here is moderation, once you get enough going and people start to use it, you need to have a little bit added to the pool of money once...
I was thinking about the electricity load as well. But if you can tap into the main breaker (power company/house one) and with a little electrical engineering knowlege, you can build a fairly high current "new" break to supply a very high load. If you are willing to drop $50k on these cards...