To be honest, the title was more promising than the content, I would love to be able to create artifical suns (@ GT bei zuerstörung von fusionsreaktoren) It is true that it would enable infinite amounts of energy. But we are talking about an little star you can give it a reasonable prize for example.
1. As you create the "sun" the is explosion of nuke range
2. In order to create artifical cold fusion you need a crazy amount of energy.
3. In order to do this you need to create deuterium, you probably have to syntesize it in a pretty high tier machine
This Energy could be transmitted In Lasers focusing on a cell of concentrated Deuterium which would initialize the reaction. These lasers would require diamonds and are due to the explosion only useable once.