Story related and CAN NOT be missed. Contains spoilers. First is quick form but more detailed is after.
- Talk to Scooter.
- Take Eridium.
- Find two fuel cells in his garage.
- Put them in the hatches in middle of town.
- Go buy something from Crazy Earl.
- Put final fuel cell in place.
- Go to Rolands place.
- Talk to guy outside.
- Unlock door.
- Pick up message.
- Achievement unlocked.
After you get to Sanctuary you have to go talk to Scooter and help him with the defences. Take the Eridium from him and then you have to find two fuel cells in his garage, highlighted on map so not hard at all. Then you have to go into center of town and put them into a hatch.
Take that Eridium and go to the Black Market (Crazy Earl) and buy whatever you want and you'll get the third fuel cell after you do. Place it in the final hatch and it won't work so you have to go see Roland at his place. He's not there but he left a message for you, talk to the guy outside to get a key, open the door, and directly inside is the message and bam, achievement unlocked.