During the First World War, the Union Iron Works Powerhouse was the main electrical generating plant for the Alameda Works of the Union Plant, a division of the Bethlehem Shipbuilding Corporation. The Alameda Works was the largest shipbuilding plant on the Pacific Coast. The powerhouse was the first PG&E substation in Alameda, a city with its own Bureau of Electricity. The power requirements of the shipyard were so great that it contracted with PG&E in 1916.

The classical revival building, designed by Frederick H. Meyer, is an excellent example of a building type common in the early 20th century, the beautiful power house. Meyers was one of the architects most closely associated with the design of classical power houses for PG&E.