Syndicate

This will unlock naturally as you play the game. And like all of the achievements, can be unlocked in SP or Co-Op.

When it says energy it's referring to the energy to power your applications. Which you get from adrenaline. Which you earn from killing enemies. So, long story short: Use your apps, then kill.

You can view your progress from Main Menu > Extras > Player Statistics > Adrenaline Earned.

Credit to Sourman145 on xbox360achievements for clarifying what Energy actually meant.

Should this game glitch on you and reset all your stats like it did to me you'll be forced to grind this out in campaign. The energy gained in co-op is not tied to your score at all, so going through a full map will only award 1,000 energy or so.

I suggest loading up Mission 5, Escape From LA. Make sure to hit the back button and choosing the Adrenaline Rush chip upgrade. Go through the train and take out the 3 enemies in the first room and 4 enemies in the 2nd room using your SMG or assault rifle, breach spiking the turret in the 2nd room to assist with some kills. Pick up the minigun and proceed into the next room, taking out all 6 enemies in here using one DART Overlay. Go up the stairs and hold X on the lever in the next room. Drop back down into the room and kill the 10 new enemies in a DART Overlay once more. Go into the elevator room and activate the switch, killing the 4 soldiers at the top of the elevator and turning around.

Walk to the end of the train car and whir up your minigun, 5 groups of hovercraft bikers will attack you. Kill them all in DART Overlay. When all 5 groups are destroyed, wait for the "sync" symbol in the top right corner of the screen to signify an autosave. When that finishes, quit out of the game and start over again. You should average around 3,000 Adrenaline every 5 minutes. Hope it doesn't come to this, but in case it does prepare for a grind.

If you need to grind this out in campaign, my suggestion: Chapter 14. Once you're outdoors, go to the second "room" with the EMP mines (you go through a small tunnel/gate to get there). Once you clear it, there is a place you can stand across from the entrance tunnel on the incline of the hill that allows you to see and interact with five (5) EMP mines without moving, only turning in place. Breach spike them all in succession. Over and over and over. Put on a TV show or podcast or something. "Enjoy." Can't imagine a faster way to do this but that doesn't make this quick or fun.

Make sure to use the "energy from all sources" chip upgrade, and be sure to trigger a checkpoint before you quit out. (I do the rest of the mission to shake off my existential angst.) After-mission screen shows how much you earned (not the 100,000 score; you need to D-pad over to get the adrenaline amount). You can check overall progress in main menu / extras / stats for adrenaline. Achievement pops immediately mid-game.

Here's a clip showing the location/method: