Energy is an attribute of certain units and structures, which accumulates over time and is spent to activate (some or all of) the unit's or structure's special abilities (spells).
Energy is represented in-game by a purple bar below the health and shield bars (assuming status bars are displayed).
Units with energy generally start out with 50 energy and slowly build up energy over time to a maximum of 200. Energy is passively generated at 0.7875 energy per second on Faster speed (0.5625 per second on Normal speed).
The exceptions to the above are:
- Queens start with 25 energy.
- Ghosts start with 75 energy.
- The Shield Battery starts at 100 energy and has a maximum of 100 energy.
- Some units have an upgrade that raises their starting energy to 75 (Corvid Reactor, Pathogen Glands).
- Point Defense Drones (now removed) started at 200 energy and regenerated 1.4 energy per game second.
Most spells only cost a fixed amount of Energy to cast. Cloak (Ghost & Banshee) and Pulsar Beam (Oracle) are ongoing spells that cost an initial amount of energy to activate and also drain energy so long as they are active. The Shield Battery & Medivac spend energy proportional to the amount of shields/health they restore.
Units That Use Energy
- Nexus (except for LotV up to Patch 4.0.0)
- Shield Battery
- High Templar
Abilities Affecting Energy
Upgrades Affecting Starting Energy
The Ghost's starting energy (without any upgrades) has been switched between 50 and 75 multiple times (Patch 2.1 BU, Patch 4.0.0 and Patch 4.1.4 BU). Moebius Reactor was available whenever the Ghost's starting energy was at 50.
Behemoth Reactor was removed from the game in Patch 3.8.0 when the Battlecruiser's abilities were switched to cooldown timers rather than energy.
Caduceus Reactor was removed from the game with the release of Legacy of the Void.
Khaydarin Amulet was removed from the game in Patch 1.3.0.