One way to collect plenty of T-Energy is keep fighting the giant crab enemy in Marshall's Gorge after you receive the Acetylene Torch upgrade for your rig. Defeat the crab, fast travel to any location, then return to the Gorge again to respawn the crab and kill it again for T-Energy. You can't make the crab respawn once you complete Marshall's Gorge, so be sure to take advantage of this trick while it lasts.
Note: The magnetic hook is required. You will automatically get it after completing the main missions for the Camp Of The Forgotten (northern area on the world map). After getting the magnetic hook, go back to Shackleton's Peak. Activate the console at the bottom of the mountain to call the gondola. Use the gondola to immediately reach the summit. You will then have to do some backtracking. Go through the door, and down the mountain where you previously came from when you climbed the mountain for the first time. Proceed until you reach a point where you can use the magnetic hook. It is about a minute walk from the summit (on the left side of the path). Use the hook, and keep going until you reach a hidden cave. In that cave is the Lost Contractor. Pick up his audio log to get the "Lost And Found" achievement.
To make Albino Tarkaa monsters appear, enter the upgrade shop in the western corner of the Camp Of The Forgotten. A conversation with the vendor will automatically start, and he will give you a quest to locate the rare Albino Tarkaas for him. You will be given an upgrade that allows you to hear the noise they make. Leave the camp and go to the Killing Fields. There is an Albino Tarkaa in the mountain cave to your right. You must use the claw of your rig and the magnetic hook to reach it. The Albino Tarkaa is on one of the walls; it is small and white. Scan (tag) it with your pistol to get the "First Tag" achievement.