|"Thanks to your nano-systems, you are not entirely organic. If an EMP weapon hits you, your bio energy reserves will be drained severely."|
|— description of EMP Damage, Deus Ex: Invisible War|
Being machines, both the heavy machinery used in mechanical augmentation and the nanites used in nano-augmentation require a power source to function. Bioelectrical energy is the electrical energy that powers these devices. In Deus Ex and Deus Ex: Invisible War, the player has internal "batteries" that contain a limited reserve of bio energy, and both using augmentations and being hit by EMP weapons or electrical attacks will drain this reserve. When the energy meter is empty, the player cannot use augmentations. The player's bio energy can be replenished through the use of bioelectric cells, but the Power Recirculator aug can conserve the amount of energy used.
In Deus Ex: Human Revolution, Adam Jensen must consume energy bars or paste to replenish his energy cells, with only the first (two in the Director's cut) of a possible five energy cells automatically recharging.
By the events of Deus Ex: Mankind Divided, the first true biocells have come into use. They are backwards compatible with the majority of augmentation energy systems, offering a much more efficient alternative to protein bars. In addition, they are used to power everything from personal safes to powered armor.