There are generally two ways to power systems that require large amounts of energy to function, such as weapons systems, defensive systems and faster then light drives. There is the direct method, which channels power directly from a reactor into the system in question. Then there is the indirect method, which channels power from a reactor into a capacitor system first then into the system in question.
Each method has its good points and bad points which will be explained in detail. With the direct method there is less systems that could fail or become damaged so less chance of mechanical failure interrupting the flow of energy. However, an energy reactor is only capable of producing so much energy per second and if you try to draw more energy then it can produce in a given time there are three possible outcomes. One is that the system being powered works but at a reduced capacity, another is that the system does not work at all do to insufficient power, the last and worst outcome is that the draw on the reactor is so great that it stalls out and shuts down. The indirect method allows for the same reactor to supply the needed energy to power a system that caused it to stall out by storing energy in temporary battery system or capacitor. A capacitor is capable of storing a large amount of power and discharge it quickly, it also is capable of recharging even during discharge. A capacitor however is only a temporary means of storing energy, if a constant feed of energy is not going into it the device will slowly leak the energy inside of it till there is nothing left.