Star Wars Knights of the Old Republic II: The Sith Lords/Secret Tomb

Shyrak Cave
Within the secret tomb, Force point regeneration rate is doubled for a dark side (alignment 0-40) character, whereas a light side (60-100) character regenerates no Force at all unless using items with Regenerate Force Points bonuses.

Cost of Force powers is also reduced by 5 if dark side and increased by 5 if light side, after alignment adjustment but before any Force form increase.