ANAHEIM, CA - APRIL 16:  Kylo Renn's Costume on display inside the 'Star Wars The Force Awakens' exhibit on Day One of Disney's 2015 Star Wars Celebration held at the Anaheim Convention Center on April 16, 2015 in Anaheim, California.  (Photo by Albert L. Ortega/Getty Images)
TV - Movies
Why Kylo Ren
Can't Use Force
Lightning In
Star Wars
By JACOB WILLEFORD
In the sequel trilogy of "Star Wars" films, Kylo Ren and Rey are shown to be incredibly powerful Force wielders on their own by the time "The Rise of Skywalker" comes around. In one particular scene, Rey summons the advanced skill of Force lightning, but many have wondered why Kylo could not use this.
It's entirely likely that Kylo never completely learned how to harness Force lightning, as he was trained by Luke, who ensured he stayed within the limits of Jedi training. When Kylo turned, He received his Sith training from Snoke (really Darth Sidious), and Sidious always made sure to keep his apprentices in check so they wouldn’t overthrow him.
Additionally, Darth Vader does not use Force lightning, as it would kill him, due to his injuries. Kylo is obsessed with his grandfather, making it possible that he could have abstained from using Force lightning simply in an effort to be more like his grandfather.
Being a Palpatine, Rey likely already has some kind of genetic predisposition to Force lightning. Since she and kylo make up a Force dyad, it could be possible that Kylo can summon Force lightning, despite having no lineage of Force lightning users.