ABOUT GEM

Georgetown Energy Museum is a fully functioning and operational Hydroelectric generating plant in Georgetown, Colorado. The plant is owned and operated by Xcel Energy. It has been in operation since1900.

There are two generator-water wheel sets. Each set has the maximum capacity of 720 kilowatts, bringing the total capacity of the plant to around 1.5 megawatts of Alternating Current electrical power. This is approximately enough power to support 700 to 1000 homes and businesses. Typically a modern home of today is rated at 1500 watts usage.

The water wheels are of the Pelton design which claims to have a 90% efficiency rating. The water used to drive the water wheels comes from the Georgetown reservoir located approximately .9 mile up the canyon towards Guanella Pass. That gives the water a 700 foot vertical fall which produces 275 pounds per-square-inch of water pressure at the water wheel. The water is delivered to the wheel by a 30” penstock or supply pipe.

275 pounds is more pressure than the wheel needs to turn the generator so a “needle valve” is used to control the speed of the wheel at 360 RPM. The speed of the water wheel has to be kept at 360 RPM so that the directly-coupled generators speed is kept at 360 RPM. At that speed the generator will produce 60 hertz or 60 cycles-per-second of electricity. 60 Hertz is necessary for the generators output to be synchronized with the distribution grid.

The electricity that is generated here is added to the substation located at the south end of the power plant, where a transmission line from the Colorado distribution grid also feeds the substation. This substation, in turn, feeds Georgetown, Silver Plume and a transmission line that travels north to Empire and the Henderson mining operation.

The fore mentioned “needle valve” position is controlled by an electric motor at the right side of the water wheel. The electric motor is controlled by way of a computer and a communications link from the Cabin Creek hydroelectric plant. Cabin Creek is a modern pumped storage hydroelectric plant located approximately five miles up the canyon towards Guanella Pass. All of the maintenance and monitoring of this plant is done remotely from Cabin Creek. In 1976 the construction of Cabin Creek was completed and it was added to the Colorado distribution grid.

When the plant was first built it did include an Alice Chalmers Corliss steam
engine which drove one of the generators. Due to the cost of producing steam from coal fired boilers the steam engine was only used when the water level at the reservoir got too low to turn the water wheels on.

There isn't any coal in the surrounding mountains so all of the coal used had to be brought up from Denver. This was a very expensive proposition. The economics of free water to expensive steam retired the steam engine and boilers very early in the history of the plant. To get away from steam generation the operators of the plant moved the reservoir, also known as the forebay, from the original location to the present location in 1902. They also added pipe lines from Green Lake and Clear Lake to the forebay capacity. This took care of the low water problems and the need for steam generation. Although the steam generating machinery was retired before the first world war, the boilers and the engine were not removed until 1918.

In 1893 the Georgetown Electric Light and Power merged with the Gas
Company and was named United Light and Power Company. In February of 1906 Green and Clear Lake Company, Cascade Electric Company and United Light and Power Company merged to form United Hydroelectric Company. Then in July of 1916 the United Hydro Electric Company was sold to Colorado Power Company. Colorado Power Company was a conglomerate of several other Colorado power companies. In 1924 Colorado Power Company was renamed Public Service of Colorado. In 1999 Xcel bought out Public Service of Colorado.

The same year, 1893, that the Gas Company and the Electricity Company merged they built a two and a half mile transmission line into Silver Plume. In 1900 a transmission line was built up to Lamartine, a small mountain mining town high above and several miles to the east of Georgetown. In 1901 this line was extended down the mountain to the north and into Idaho Springs. By December of 1902 the plant was contracted to supply electricity to Black Hawk and Central City as well. So by 1903 the plant was supplying electricity to Georgetown, Silver Plume, Idaho Springs, Black Hawk, Central City, and any of the mines in the area that were electrified.