As a hydro-electric plant in the US it was predated by the Oregon-based Willamette Falls Electric Company, the first AC hydro-electric generation facility, in 1889, which included a 14-mile-long (23-kilometre) transmission line to Portland, used to power arc lighting. The oldest hydroelectric power plant supplying a commercial transmission system for alternating current was the power plant Thorenberg near Lucerne in Switzerland. The plant started operation in May 1886 and fed 1,800 volts to a nearly transmission line. It was transformed to 100 volts to illuminate some hotels and restaurants in the downtown area of the city.