Helios One Energy Plant

The plant itself was owned and built by Poseidon Energy prior to the Great War. In addition to providing electricity to the Vegas area, it was also used to install a new solar powered weapon named Archimedes II. Previously, the plant was occupied by the Brotherhood of Steel.
 
In the post-apocalyptic world of Fallout: New Vegas, the plant is occupied by the New California Rangers, who wish to reactivate the plant for their own ends. The NCR already have a technician called Fantastic attempting to reactivate the laser; however, he is struggling and the NCR may ask the player to replace him.

The player character can choose to assist them in this venture if they have the relevant skills or, alternatively, supersede control of the plant and use it to supply power to the wasteland, or fire up Archimedes II in a similar manner to destroying Megaton in Fallout 3. The solar tower is used to control an orbital laser platform which the player may use, even obtaining a remote control device that can be carried throughout the wasteland.

The plant gets its name from Helios, the Greek sun god. This follows in the footsteps of its parent company, Poseidon, named after the Greek god of the sea.