Power Generators are used to generate the primary electrical power for all of Apollo. Steam is fed from the Reactor Core to the generators via underground lines. Steam spins the turbines connected to power generating stations, creating electricity. The generators are particularly important for opening the gates of Apollo. The Power Generators can be activated as part of Bonus Mission Restart the power Generators in the Easy Company and Apollo Security Team campaigns.
There are 5 generators in total, but only four need to be activated to give control of the gates and open them. The generator locations are: southwest of the Airlock, southwest of the Military Base, east of the scrapyard gate, southeast of Apollo's east gate, and west of Apollo's north gate.