These brick structures were built as a gas plant in 1884 and were the first large scale source of power in Key West. Electric power was in its infancy during the late 1800s. Transmission and distribution of electricity was not available in the Florida Keys and there was a strong reluctance by the public to move from gas power to the relatively new invention of electricity.In the early years of gas plant operations, the goal of a utility gas works was to produce the greatest amount of illuminating gas from coal.The raw ingredient in the process of producing gas was coal or high grade coke. When coal is burned it produces a byproduct called coke. Air was passed over bins of red-hot coke and funneled into collecting tanks. The illuminating power of a gas was related to the amount of soot-forming hydrocarbons dissolved in it. These hydrocarbons gave the gas flame its characteristic bright yellow color. The gas was "scrubbed" before delivery and piped to street lights, businesses and for residential uses.The coal gas produced in this plant was smoky and proved to be an inefficient and inadequate lighting source. The company foundered until, in 1890, John Jay Philbrick acquired a controlling interest in the plant and transformed the facility to a steam powered electric power plant. It was renamed the Key West Coal and Electric Power Company.Two years later he abandoned the production of coal gas and concentrated on steam powered electricity. Coal was still a vital element in the production of electricity. It was used to heat industrial boilers filled with water creating steam that powered pistons of electric power generators.Upon J.J. Philbrick's death, his heirs consolidated the plant with William Curry's power plant. Curry's plant had been the sole large scale competitor of Philbrick's plant. A few years later, the combined power plants were purchased by Stone and Webster, an electrical engineering company based out of Stoughton, Massachusetts.Today, Key West gets electric power from the mainland via transfer lines spanning the 120 mile stretch of islands and open water between Homestead, Florida and Key West. The historic plant buildings are currently owned by Keys Energy who maintain the tradition of this location being a power source for the community with a modern electric transfer station in the building courtyard. A small diesel powered electric power plant on Stock Island is maintained as backup source.