Energy is a non-tradable currency acquired from various sources detailed below, and that can be spent in various ways, from battling in the Battle Arena or Plains, to upgrading a Mech's base stats, or even working for Credits at Mech Donalds or the Bar.
Commonly abbreviated MaxE, this is your current daily allowance of energy. You regain Energy equivalent to 1/24th of your Max Energy each hour. The only way to raise this value (other than by applying Pack Credits) is to win battles in either the arena or plains.
The amount of MaxE gained from each commander within a level varies depending on the rank (Total skill) of the target. When hitting targets in the same level bracket as yourself the highest ranked target in a level bracket gives an increase of 1.1/MaxE, while the lowest ranked target gives an increase of 0.9/MaxE. The other targets in the bracket will give a linear variation depending on their position in the ranking. When hitting below your level the maximum gain is reduced and when hitting above your level the minimum gain is increased.
In 2016 a catch up mechanism was introduced where those with below 1000 MaxE receive tripled MaxE gains, those with between 1000 and 2000 MaxE receive double gains, and those over 2000 receive standard gains.
This is where the energy accumulated from the hourly gains, coffee consumption and answering the QotD correctly is stored, and this is where any energy spent is taken from. The storage limit is three days' worth or energy, though it is seven days' worth for VIC players.
This is where the energy gained from voting, Drazil battle victories (as well as any Energy bought by applying Pack Credits) is stored. Energy can be transferred from the Reserve to your standard storage at any time, but cannot be transferred from standard storage to Reserve. You cannot transfer more into your standard storage than what you would normally be able to store. You cannot spend energy straight from the Reserve.