@ Powercrazy:
Were did you read that this should be micro-managed ?? And I doubt that you can use a energy weapons and the energy-system behind them without any loss within the system (repair -> spare-parts

).
@ Impaler:
True, but to keep a closed system running you need at least spare-parts in order to repair defective parts of the system. Besides that, you can't have a system with 100% efficiency, and the area under crops to supply hundreds of crewman would need huge habitats. Besides that, it would be just one or two if-statements and a formula-based crew-reduction (supplies hit the red mark: each round 25-30%, supplies reach deep-red mark: old_crew * 0.5 ).
[edit - response to below post, since I dont want to creat a new post]
a game... well, thats true, I almost forgot it, thanks for reminding me

Well, the weak point is not the weapon itself, but the energy system. Having no spare-parts to replace, eg blown fuses, doesn't allow you to run at 100% efficiency, therefore you can't fire with full-power or load-times increases...