Poseidon Energy Poseidon Energy is a pre - War company in the " Fallout " series of games . History . Easily the most powerful and influential energy conglomerate in the United States , or even the world , prior to the Great War , Poseidon Energy was an umbrella corporation with its fingers in virtually all known forms of renewable and non - renewable power sources , as well as R & D for new , more technologically advanced weapons , through their subsidiaries , so long as they remained consistently profitable . Although most of the pre - War public knew that Poseidon was a huge corporation and never particularly trusted it , very few people were actually aware that several companies owned by Poseidon were given lucrative defense contracts by the U . S . government – or even , by the Enclave . Most of Poseidon ’ s most promising research projects never reached their final stages however . Though ultimately not a part of the Enclave , many powerful corporations benefited from the Enclave ' s actions and their research facilities were shielded from the atomic firestorm of 2077 . Poseidon Energy was one of these , as its facilities continue to be used by the the Enclave following the Destruction of Control Station ENCLAVE . Locations . Gas stations . Many Poseidon Energy gas stations can be found across Western America as the company was competing with Red Rocket stations in the East . Most notable ones are located in the Mojave Wasteland . The stations generally consist of a small main building , for a general store , and possibly a garage on the side for repairing cars . Most have a large elevated roof over top of the gas pumps , similar to the Red Rocket stations of the east . Some notable examples are the Goodsprings gas station , Novac station , the Nipton Road reststop , and the El Dorado Gas & Service . Energy and power plants . As Poseidon Energy is an energy - producing company , the company naturally owns many energy and power plants . The most notable ones are HELIOS One , Poseidon Energy ( location ) , Poseiden Energy Turbine 18 - F , and there are many other examples in Capital Wasteland , the Mojave , and around Boston . After the Great War , Poseidon no longer existed as a real force in the post - atomic world . However , highly technological factions such as the Brotherhood of Steel and the Enclave still tried in vain to decipher Poseidon ' s plans and either confiscate this technology or turn them into working models , respectively . Notes . Poseidon Energy was not a single , monolithic company , but was rather a cartel of various Poseidon - owned corporations controlling various aspects of the global energy market ; the PoseidoNet data transfer system provided instantaneous communication between various Poseidon facilities including the Poseidon Oil Reactor № 5 , the Enclave Oil Rig , and other locations throughout the United States and possibly even the world itself . . . Appearances . Poseidon Energy , or some of its divisions are referenced in " Fallout " , " Fallout 2 " , in the canceled " Van Buren " , " Fallout 3 " , " " , " Fallout 4 " , and " Fallout Shelter " . Behind the scenes . was the Greek god of the sea as well as horses and earthquakes . His weapon and symbol is the trident . Poseidon ' s projects often used codenames drawn from Greek mythology .