The Bio Reactor is one of Epsilon's most important structures, which provides power for their bases in a rather unorthodox way when compared to other power plants, using infantry as a source of energy.
Yuri's unethical technology begins at the very roots. The Bio Reactor is the main power supply for an Epsilon base, with a twist. The Bio Reactor can generate more power when infantry is placed inside it, drawing energy from their natural bio-electricity.
It is not uncommon for victims of mind control to end up as additional fodder for these structures. As the mind controlled subjects are sedated and remain unconscious while inside the reactor, this allows the controller to safely break the link and control another victim.
On its own, the Bio Reactor is able to provide power equivalent to a Tesla Reactor, which is the weakest power source in the game. Unless the proselyte orders infantry to garrison them, "empty" Bio Reactors aren't enough to satisfy the power needs of advanced structures and defenses (especially since they have no defense that requires no power except the Tank Bunker).
Otherwise, the Bio Reactor is the second most efficient basic power plant after the Foehn Windtrap when fully garrisoned, granting a total of 400 power units. Thus, Spooks are recommended as primary occupants of Bio Reactors due to their cheap cost, as well as the added benefit of discouraging enemy infiltration since said units are capable of detecting and killing them with ease as long as the proselyte is attentive enough to manually order Spooks to evacuate the Bio Reactor. Mind-controlled infantry are also another option to consider if the proselyte doesn't need them for combat or recycling via Grinder, freeing the link of its mind-controller and allowing it to take control of another unit. However, if the Bio Reactor is destroyed, the mind-controlled infantry will become loyal to its original allegiance again, and become a nuisance to the proselyte.
- The Bio Reactor makes its debut as a buildable structure in The Conqueror alongside other Epsilon buildings.
- In Hysteria, one of the objectives is to capture enough Bio Reactors and use them (with the assistance of civilians) to generate 4000 power and satisfy the power requirement of the Supercharged Paradox Battery. The power sources (whether they be these Bio Reactors or Power Plants constructed by the player) need to be protected for 25 minutes; if the player's power demand (including that of the battery) exceeds the supply for 1 minute, the battery will fail and the mission ends in a failure. The locations of all Bio Reactors are revealed when the Radar Spire is captured.