Helioptile will make its Pokémon Go debut during the new Power Plant event, meaning players will have another species to catch and evolve if they want to keep their Pokédex up to date.
The Electric/Normal-type from Kalos will be found more frequently during the Power Plant event, which will run from Jan. 19 to Feb. 1. And during that period, getting the necessary resources to evolve your Helioptile into a Heliolisk will also be easier.
Normally, in order to evolve a Helioptile into Heliolisk, players would simply need to use a Sun Stone. Because Pokémon Go utilizes different methods for evolutions, this specific change will require both a Sun Stone and 50 Helioptile Candy.
Because Helioptile is such a focus for the Power Plant event, it is very likely Niantic will include Helioptile Candy and a Sun Stone as part of the event-exclusive Field and Timed Research in some form. That doesn’t mean it is guaranteed, but that is typically how the developers handle the introduction of new Pokémon.
If that doesn’t end up being the case, you can use Pinap Berries while Helioptile is set as your Buddy Pokémon to increase the amount of Candy you obtain per milestone. Additionally, you should be able to collect enough Helioptile Candy by simply catching the Pokémon multiple times during the Power Plant event.
As for a Sun Stone, there is currently no surefire method to grab one, but if you don’t have one saved up, you can obtain them as a drop for spinning PokéStops.