The energy is compressed into a very short pulse. So you have a single pulse obtained in smal period of time and has very powerful, but power consumption is relatively small. This is called power compression. This is how, for example, Marx generator works. Charge the battery of capacitors, and then all of a single key discharged. But those systems, of which I speak, use other principles. I will not explain them in detail because I do not want to be a teacher for the younger generation of terrorists. But I will say that using the new systems that store and compress the power devices can be made quite small.
Thats how are made electromagnetic bomb, the heart of free energy device!