The Energy Tank is a common Suit Expansion in the Metroid series, featured in every Metroid game to date. The Energy Tank is used to increase Samus's maximum energy by 100 units (with the exception of Hard Mode in Metroid: Zero Mission, where each Tank increases Energy by 50). They also refill Samus's energy to full upon acquisition. Extra Energy Tanks are represented by small boxes near the top of the HUD. These, like other expansions, are not required to progress through the games' plots, thus creating two challenges: completing the game with all the Energy Tanks acquired, and completing the game with the least amount of Tanks possible acquired.
Samus must use her Morph Ball and Morph Ball Bombs to crawl through a tunnel in the ceiling of the room where the first Chozo Statue of the game resides; the Tank is at the end of the tunnel.
After obtaining the Varia Suit, Samus must travel backwards to a corridor filled with acid, then access a tunnel down under the acid; the Tank resides at the end of the tunnel.
After ending Kraid and obtaining the Speed Booster, Samus must travel to a corridor with several bugs flying around. She must then Shinespark through several blocks that block access to the Tank.
While traveling through Ridley's lair, Samus encounters this Tank sitting plainly at the end of the corridor. However, the path to the Tank is lined with fake blocks, so Samus must tread carefully to reach it.
After defeating Ridley, Samus must travel to a corridor with pipes that send out bugs, then lay a Morph Ball Bomb near the entrance of the corridor to access a network of tunnels; the Tank is at the end of the tunnel.
Samus must travel to the room outside Mecha Ridley's room, then build up enough speed to break through a set of blocks in the room to the left. She will then be able to access the Tank, but only if she succeeds in bypassing tripwire lasers.
Samus must travel to the glass tunnel that connects the Mothership with the Chozo-built portion of Chozodia, then lay a Power Bomb to break the glass, then exit through the bottom left after laying another Power Bomb to break open the wall. She must then drop down a hole, then travel to the left. Finally, she must Shinespark up through a narrow corridor until she hits the Tank.
Samus must travel to the room adjacent to the room that holds the Ruins Test, then exit through the bottom right. She must then use her Speed Booster cleverly to keep enough charge through several rooms while traveling to the right, eventually reaching a platform where she must Shinespark to reach the Expansion.
After defeating the Hive Mecha and obtaining the Missile Launcher, Samus must destroy the Missile Door Lock with a Missile to access the Transport Access North; the Tank sits plainly inside.
Samus must shoot the white-colored lock in the room with her Ice Beam, then enter the Chozo Statue's hands in Morph Ball mode. The statue rolls Samus into a small chamber with the Tank.
After defeating the Chozo Ghosts located in the Training Chamber, Samus must use a Half-pipe in conjunction with her Boost Ball to activate a Bomb Slot high up in the room. This activates an elevator that leads up to a set of Spider Ball Tracks that leads to the Tank.
When Samus rolls through the tunnel to access Phendrana Drifts, she must use a double bomb jump three times to climb up to this Tank high up in the network of tunnels.
Samus must activate three conduits using the Wave Beam along with the Thermal Visor. After activating the third one, she must roll through to a small chamber; the Tank is inside.
Samus must activate two Bomb Slots to restore power to a Spinner, then activate the Spinner using her Boost Ball, thus raising the water level. She must then jump across the ice floes using her Space Jump Boots, accessing a platform with a tunnel she must enter as Morph Ball. The Tank is at the end of the tunnel.
Samus must lay a Power Bomb to destroy a grate in front of a fan, then activate a terminal with her Scan Visor to turn on a fan. This blows a large number of Puffers into another fan, revealing the Tank.
After defeating the Omega Pirate, Samus must exit the Elite Quarters through a Red Door on the upper level of the room. The Tank is in plain sight once she enters the Processing Center Access.