I played this StarCraft II map a lot called Cruiser Command and I got pretty good at it. What that game did was your cruiser's reactor had a constant energy output (started at like 150gw per second then you could upgrade for more) that you could direct wherever or store in your capacitor to be used later. I don't think that would be hard for this game. Maybe like:
2cp buys you a 1gw/turn reactor
4cp gives you a 2gw/turn
8 gives you 3gw/turn
16 = 4gw/turn
32 = 5gw/turn
However many gw you get, multiply that by d12s for if the reactor gets destroyed that's how powerful the explosion is and 2" radius per level.
2cp gets you a 2gw capacitor
4 cp gets you a 4gw cap
8 = 6 gw cap
16 = 8 gw cap
32 = 10gw cap
You can't store more energy than your capacitor holds. Capacitor, if destroyed, releases an explosion of size 2" per stored gw and 1d10 damage per gw, so if it had 4 gigawatts it would be a 8" 4d10 explosion.
Then you can spend your gw of power on whatever. So if you want to boost engine output by 1d6 inches you get that d6 by spending 1gw from the capacitor or directly from the reactor. Want to increase shield output for 1 turn by 2d6? Spend 2 gigawatts to do it. It's very simple.



