Crystals transfer energy without cables. Click a crystal with the 
Crystal Binder (select), then the
next one (link, again = unlink).
The 
Energy I/O Crystal sits at machines/cables: sneak + right-click = input (grid → crystals) or output
(crystals → grid). The 
Energy Relay Crystal distributes (8 links, 32 blocks), the
Draconic Relay Crystal 16 links, 64 blocks.
Crafting Table3 × 3
1 × Crystal Binder
Crafting Table3 × 3
22 × Energy I/O Crystal
Crafting Table3 × 3
44 × Energy Relay CrystalThe 
Wireless Energy Crystal charges up to 16 machines directly: select the crystal, then click the machine.
Only your own blocks can be linked.
Crafting Table3 × 3
1 × Wireless Energy Crystal