Energy parts in Metroid Other M will be useful as 4 energy parts get you 1 energy tank. There is a total of 16 energy parts to explore. You can refer to the guide below for the location of all these energy parts.
Metroid: Other M Energy Parts Location Guide
Energy Part 1 (Main Sector)
In the elevator room, you need to get to the top to have this energy part.
Energy Part 2 (Sector 1)
If you move right from the Wasp hive, you will find a hallway. Use the ramp and ultimately you will find a morph ball tunnel. Destroy the barrier to get to the charge.
Energy Part 3 (Sector 3)
At the location of large lava pool in northeast direction of the sector, a spot will appear on your map once you have cleared all the men in perimeter. Climb over the rocky path and find the morph ball tunnel. Enter it to reach the charge, you need to destroy the blockages found in your way.
Energy Part 4 (Sector 3)
It is in the room where you drained the larva. To the west of the room, there is a hole. This hole will lead you to the charge.
Energy Part 5 (Sector 3)
To the northwest direction from the lava pool, search for the room with ramps. The energy part is behind a vent on the west wall of this room. Use the green glowing portion to get to it.
Energy Part 6 (Sector 2)
In the room having water filled tubes, you will have this part at the bottom. So instead of going up, move downwards. Use the bombs (Morph ball) to destroy the hurdles to expose the hole leading to the part.
Energy Part 7 (Sector 3)
Find the room with lava pools and grapple points. Use them to head east. Jump from the ledge that will lead you to a tunnel pathway which ultimately will lead you to the energy part.
Energy Part 8 (Sector 2)
It is in the room where you fought with the Mech. Space jump to get to the top of the crates. Now shoot the crates on the roof to have your energy part.
Energy Part 9 (Sector 1)
In the waterfall room, use the Shinespark (you obviously have to run some area to use it) to reach the top. Space jump to head to the ledge. Now use your Grapple point by your Grapple gun to reach the energy part.
Energy Part 10 (Sector 1)
The place where you fought with the wooden villain, where there is rain too, kick climb to the northwest corner. Head to the glowing panel and activate the panel nearby. This will result into some platforms emerging on the wall. Jump using the second one and you will have the energy part at one corner.
Energy Part 11 (Main Sector)
Run in the circle in the room found in Bottle ship residential area to activate the Speed booster. Using the Shinespark, jump to the ledge above to have the energy part.
Energy Part 12 (Sector 2)
Look for a a hall with automated cart. You need to wake up the bug and then execute it. You can use your power bomb to do this. Enter the opening leading to a room. The rooms contains the energy part.
Energy Part 13 (Sector 2)
In a room containing many glass tanks is a power bomb door to its west wall. Use the power bomb to get the energy part.
Energy Part 14 (Sector 1)
Near the overgrown room is a hallway with 2 grapple pints. Use them to reach the secret ledge above. You will have to use the space jump to reach the ledge. You can find the energy part on the ledge.
Energy Part 15 (Sector 1)
If you head north from the navigation booth, you will find a Power bomb door on the eastern wall. Destroy it and get the energy part.
Energy Part 16 (Sector 3)
It can be found at the place where you found Anthony and had your Grapple gun. You will have to use a super missile to break through the door.