can prototype portal,lotus bloom, and voltaic key do infinite mana?
Actually this doesn't work because you're not untapping {Voltaic Key}. Add {Kurkesh, Onakke Ancient} to copy the untap for the key to untap itself and you've got yourself infinite mana.
{Prototype Portal} exiling {Lotus Bloom}.
Tap {Prototype Portal}, get a {Lotus Bloom}.
Sacrifice the {Lotus Bloom} for {R}{R}{R}
Pay {R} to tap {Voltaic Key} and untap {Prototype Portal}, pay {R} for {Kurkesh, Onakke Anchient}'s ability to untap {Voltaic Key} as well and net {R}.
This nets infinite of any color because once you have infinite red you can start tapping the {Lotus Bloom} for whatever you need.