Ames Hydroelectric Generating Plant
| Company type | Hydroelectric power station |
|---|---|
| Industry | Electricity generation |
| Founded | 1890 |
| Headquarters | Ophir , United States |
| Products | Electric power |
| Owner | Public Service Company (subsidiary of Xcel Energy) |
The Ames Hydroelectric Generating Plant, constructed in 1890 near Ophir, Colorado, ranks among the earliest commercial facilities to generate and transmit alternating current (AC) electricity for industrial purposes, as well as one of the pioneering AC hydroelectric stations. Operational since 1891, it was developed by Westinghouse Electric and utilized two substantial alternators: one powered by water in the valley serving as a generator, linked through a transmission line to a second alternator functioning as a motor at the Gold King Mine. The facility has undergone various upgrades over time and continues to operate, earning recognition on the List of IEEE Milestones.
History
Lucien L. Nunn, a principal investor, aimed to find an economical substitute for wood-fired steam mills to power a stamp mill at the high-altitude Gold King Mine near Ophir, Colorado. Due to limited timber resources and inaccessible coal, traditional fuel sources were impractical. The nearby San Miguel River presented a potential energy source; however, conventional power transmission techniques were unsuitable. Electrical engineer Paul Nunn proposed utilizing high-voltage AC as the most viable option, which led to a partnership with Westinghouse Electric in 1890 to implement an AC-based system.
The design and installation were carried out by Westinghouse engineers including V.G. Converse, Lewis B. Stillwell, Charles F. Scott, and Ralph D. Mershon, with assistance from Cornell University students. Delivered in summer 1890 and installed during the winter months, the system comprised two identical 100-horsepower Westinghouse single-phase alternators—the largest units of their kind at that time. One generator was located in Ames near Ophir where the Howard Fork and Lake Fork streams merge into the San Miguel River; it produced 3,000 volts at 133 Hertz single-phase AC, driven by a six-foot Pelton wheel powered by water from local streams and reservoirs under significant head pressure.
Electric power was transmitted over two bare copper conductors suspended on poles at an estimated cost of about US$700—roughly 1% of what a direct-current line would have required. At the mining site, the second alternator operated as a synchronous AC motor to drive the stamp mill, assisted by a smaller single-phase induction motor based on Tesla patents licensed by Westinghouse to start the main motor.
Continuous operation commenced on June 19, 1891, with 15 to 20 operators required due to primitive control systems that included solenoid gravity balance voltmeters and ammeters mounted on wooden panels. Power connections were managed manually using knife switches; shutdown procedures involved physically disconnecting lines at poles—a dangerous task that generated lengthy high-voltage arcs. Equipment was frequently damaged by lightning strikes; alternators were insulated using paraffin-soaked oak platforms and protected with various lightning arresters. Components were designed for easy removal to facilitate maintenance.
Building on this initial success, the Nunn family extended similar AC electrical systems to other mining sites. In 1896, Ames was upgraded to a two-phase system incorporating new generators, induction motors, and step-up transformers that increased transmission voltage to 10,000 volts for longer-distance delivery; water supply infrastructure was also enhanced.
Eventually, Ames became part of the Nunns' Telluride Power Company, which was later merged into Western Colorado Power Company—a subsidiary of Utah Power and Light. In 1992, Public Service Company acquired Ames along with other assets from Colorado Ute.
A powerhouse constructed in 1905 remains operational under Public Service Company (a subsidiary of Xcel Energy) featuring two Pelton wheels driving a single 1904 General Electric generator producing 2,400 volts at 1,082 amperes operating at 225 RPM.
Importance in the Evolution of Electrical Power Supply
Constructed during a period characterized by the swift rise of alternating current (AC) for electricity transmission, the Ames power station played a pivotal role amid intense rivalry. Westinghouse was contending with other AC companies as well as Thomas Edison’s direct current (DC) Edison Electric Company, fueling the well-known "war of currents." The Ames installation was regarded by Westinghouse as a crucial showcase for their AC technology, which had been under development since their initial AC transformer lighting project in Great Barrington, Massachusetts in 1886.
The 1891 Ames Hydroelectric Generating Plant ranks among the earliest facilities to generate and transmit AC power for industrial applications. It was commissioned one month before the Lauffen Dam to Frankfurt transmission system, which was exhibited at the International Electrotechnical Exhibition and powered lighting and some machinery.
Within the United States, this plant followed Oregon’s Willamette Falls Electric Company (1889), recognized as the first AC hydroelectric plant using a 14-mile transmission line to Portland that supplied arc lighting. On the international stage, Switzerland’s Thorenberg station near Lucerne began operation in 1886, delivering 1,800 volts across nearly three miles to illuminate hotels and restaurants.
The original Ames/Gold King facility is distinguished by its pioneering use of the induction motor—a more efficient design without commutators—licensed by Westinghouse from Nikola Tesla two years before its construction. Engineered by Charles F. Scott, progress was hindered by technical difficulties and Westinghouse’s financial constraints. Ultimately, the company introduced their "Tesla" polyphase transmission and motor system in 1893.