I'm under the impression that lightning is not a power that any schmo can use just because they're a dark-sider and they know another dark-sider who can. It's a pretty badass power and can do quite a lot of damage, so I doubt it would be easy for a person to learn.
One might be interested by the fact that Maul uses lightning in both the Episode I movie game and in Jedi Power Battles (a loosely-based action game), but I don't think they can be taken as evidence on their own.
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