Energy is the second resource in Zero-K. Constructing any unit or building requires as much Energy as it does Metal. Your starting Commander generates 6 energy per second.
The primary sources of energy are energy-producing structures:
Most energy-producing structures may be constructed anywhere. Geothermal Generators may only be placed on geothermal vents, which are marked with a rising trail of smoke.
Energy may also be produced by Reclaiming map features which contain energy, such as trees.
Repairing and resurrecting units and buildings also requires Energy, as does operating cloaks, shields, jammers, radar and sonar.
Excess energy is automatically used for Overdrive, increasing metal output of nearby Metal Extractors.