Can be stacked with other instances of Energy Siphon for a total of 2.4 energy regeneration per second in regular missions.
It can also stack with Zenurik's Energizing Dash, reaching a total of 8.4 energy regeneration per second while in a party.
Adding Coaction Drift on a 4 player cell will give ~2.86 energy regeneration per second, stack with Zenurik's Energizing Dash ~8.86.
If the player uses a channeled ability such as Absorb or Undertow, they will not regenerate energy until they deactivate that ability.
The Sortie "Energy Reduction" condition also reduces the rate of energy regeneration.
Being idle for 2 minutes will cause the regeneration to stop.
Using only certain abilities off of cooldown, with the right build and duration/efficiency, Energy Siphon can allow a player to regenerate the energy spent on the ability before it ends, thus letting them use that ability infinitely.