Energy is used to fuel your attacks, both equipment uses and mutant powers. It recovers gradually over time both in and out of combat. Energy economy is an important, often critical factor of combat.
Energy can be affected by the following statuses: Energybreak reduces a percentage of energy requires for all abilities. There is a hardcap at 50% reducing in energy costs Powers that influence energybreak can be found here.
Energymod is the rate at which you recover energy; Mechanically speaking, it returns 1/5th of the value every 1/5th of a turn. Powers that influence energymod can be found here.
Several items also have a value in a conversation about energy restoration. Most can be given the Energized mod, and as of this edit, unknown factors govern the ability of overlapping energymod from passive effects. Several active items have energy boosting effects; Earrings, Water Flask and Ultraquench are examples of these.