Hydroelectricity arrived in Duluth in 1906 after the Great Northern Power Company harnessed the St. Louis River by building a dam at the old logging town of Thomson in the heart of what would become Jay Cooke State Park (the land for the dam had been acquired from Cooke’s estate). Prior to that, coal-powered generators provided electricity for industry. The dam was actually constructed by Boston’s National Railway Construction Company (and a variety of subcontractors) according to a design by A. H. Albertson of New York and Duluth’s own V. M. Holder. At the time it powered up, the Thomson Dam was the third largest waterpower plant in the world, and the Duluth News-Tribune called it “a water power second in potential to that of Niagara Falls.” Designed to reach a capacity of 200,000 horsepower, it drew only 30,000 horsepower in its first year, which was part of a multi-stage plan. The company quickly added three power units, and soon it was up to 75,000 horsepower. Work on the dam was completed in 1907.
Beginning during World War I, Great Northern Power merged with Duluth Edison and several power companies on the Mesabi and Cuyuna iron ranges; in 1923, this conglomerate became the Minnesota Power and Light Company. When drought depleted the Minnesota watershed in the 1920s, Minnesota Power constructed a coal-fired plant in West Duluth.
The Thomson Dam wasn’t the first time someone came up with a plan to use the St. Louis as a power source. In 1883 the Minnesota Canal Company proposed a grand idea: Starting twenty-six miles upstream from Cloquet, dig a canal 120 feet wide and 20 feet deep to the top of the hill above Duluth’s West End. From there, direct the water through giant conduits, turning waterwheels that would in turn fuel generators that would bring power and light to the Zenith City. The only problem was the cost: $7 million was a lot to raise back in 1883, today’s equivalent to about $133,750,000.