Mass Driver Question

>
> A mass driver on the lunar surface is going to require a lot of
> power delivered in a very short period. I've seen references to
> capacitors being used to unleash that power.
>
> For capacitors to be used, my understanding is that the power system
> would feed the capacitors until they stored enough energy for the
> mass driver launch. This would prevent a rapid turnover in launches.
>
> Making a trade-off by having a larger power system supplying the
> current required for the mass driver launch would insure that a
> launch could be taking place in a continuous cycle. This would
> eliminate the need for capacitors.
>
> Is this correct? OR am I overlooking something?
>
> Just to clarify: if a launch lasting one second required 20MW, then
> a power system supplying 20MW would be able to launch a payload
> every second. A system with capacitors that output 1MW would have to
> charge for 20 seconds before every launch.
>
> Just wanted to make sure I understood this properly.