Optimize the powerplant

Speak to Council member McClure in Vault City to get this quest.

Speak with Festus, he will then tell you to optimize the plant and give the optimization disk. Afterwhich proceed to Vault City, speak with McClure and run the disk on Level 3 Vault Computer. Return to Gecko and optimize the plant.

Another NPC in Gecko mentions that if the powerplant is optimized, Gecko and Vault City can trade electricity for medical supplies. Nice thought, Vault City doesn't agree - if the powerplant is optimized, Vault City invades Gecko, takes control of the city and enslaves the ghouls. Jerks.