This is a story-related achievement and cannot be missed while playing the Gaea campaign. Late in the game you are required to capture Thermopylae, an island protected by a powerful shield. You must visit surrounding islands that are powering the shield and shut down the power plants by picking up a coolant tank using the hook on a Manta and then dropping it into a magma pool that is being used as an energy source. Note that you do not need to capture the islands, although that may make it easier.
Note: the game experiences glitches that cause the coolant tanks to not spawn. If this happens, the only fix is to reload a save prior to your arrival at the island. To save yourself some time, when arriving at an island do a flyover and locate the coolant tank before attempting any significant combat operations. If the tank is not there, reload and try again.