Advanced Energy Storage Unit
There is no easy way, other than using a massive number of batteries, or setting up a temporary HV line, to relocate your base AND your energy, or to otherwise transport a large amount of energy in a small area.
this Advanced Energy storage unit would be able to hold a full 300k EU, by making use of the high capacity of energy crystals. However, to balance their ability to have only 10 of them empty a full MFSU transmitter, they are not 100% efficient, and thus will only return 280k energy when you place them back in an MFSU.
E = energy crystal, W = cable, A - advanced Circuit.