Energy

Energy is used for the operation of augmentations. All games in the Deus Ex series implement energy as a gameplay resource that is needed to use certain augmentations or abilities of augmentations. Various terms have been used throughout the series to refer to energy that is used for augmentations, including bioelectric energy, bioenergy, bio energy, augmentation-dedicated energy, and biocell energy.

Background
Being machines, both the implants used in mechanical augmentation and the nanites used in nanotechnological augmentation require a power source to function. Mechanically augmented agents use energy converters such as the Sarif Series 8 Energy Converter to generate energy from biological sources and to store the generated energy in cells known as bio-energy cells or biocells. Nanotechnologically augmented agents also have an energy reserve for energy storage, but it is said that they do not have a natural way of generating energy.

Augmented personnel can also receive energy from external sources. In 2028, biocells serve as a portable version of the energy storage cells used to power augmentations and are compatible with their internal counterparts for use in recharging.

Deus Ex
In Deus Ex, nearly all augmentations require the use of energy. Energy can be regained by consuming bioelectric cells or through the use of the Matsu-Gravas R-118 Repair bot.

Deus Ex: Invisible War
In Deus Ex: Invisible War, the Piezochem W31V Repair bot can be used to recharge Alex Denton's energy supply automatically. Invisible War also introduced passive augmentation options that do not require energy for use.

Deus Ex: Human Revolution and Deus Ex: The Fall
In Deus Ex: Human Revolution, the player may consume energy bars or paste to replenish energy. Compared to the earlier games, Human Revolution permits the player to regenerate a basic amount of energy without the use of consumables or game environment objects. In the original edition of the game, the player can regenerate one cell output of a possible maximum of five energy cells. In the Director's Cut edition, the player can regenerate two cells.

Deus Ex: The Fall features an energy system that is substantially the same as that of Human Revolution, except that the ability to regenerate two cells (rather than one) must be unlocked.

Deus Ex: Mankind Divided
In Deus Ex: Mankind Divided, the player is likewise able to regenerate energy without the use of consumables or game environment objects. However, the player's recharge limit for energy regeneration gradually decreases with repeated use of augmentations. The recharge limit can be restored to its original maximum by consuming biocells.

Trivia

 * A conversation between Walton Simons and Jaime Reyes suggests that if a augmented person keeps their bioenergy at 100% for long periods of time, they may experience an intermittent sharp pain behind their eyes.