The powerhouse contained the engines and dynamos used to generate electricity for the lamp of the 1898 south tower Fresnel lens. This brick building, built in 1909, replaced a temporary wooden structure. The engines inside were extremely loud, and local residents complained both about the noise and about the intensity of light from the south tower. Blackout panels were installed on the landward side of the tower, but the noise could not be reduced. In 1917, when the machinery required expensive repairs, the Light House Board chose not to fix it and instead replaced the electric lamp with an incandescent oil vapor lamp, which remained in use until 1924, when commercial electrical power became available. The original machinery was removed in 1921, broken up, and discarded. The powerhouse now serves as an exhibit building displaying Twin Lights' south tower Fresnel lens, whose 25,000-candle power made it one of the brightest beacons in the United States.
