Granite Power Plant - Utah Power Company


The Granite Power Plant at the mouth of Big Cottonwood Canyon - c.2011 / Donald K. Winegar - Tintic Images

Brief history

In 1896 the Utah Power Company was organized by the directors of the Salt Lake City Railroad Company, many of which were prominent Utah mining men. The company was created with the express purpose of building a hydro-electric power plant that would replace the steam powered plant that was then providing electricity to the rail company streetcars. They would end up building two. The lower, eventually called Granite plant, and the upper, named by the company directors as the Stairs plant.

Construction began on both plants that same year. By February of 1897 the Granite plant was in full operation. Though unreliable at first, in time, it would would prove itself and begin taking on contracts to provide power to entities other than the railroad. In 1898, such a contract was let to provide power to the Pennsylvania Smelting Company operations in Sandy.(1) The rest, as they say, is history. For the most part, the plant has been in continuous operation since that time.

Power is generated by way of water powered Pelton-wheels turning a 12,000 volt generator. Today that water provided by an underground pipeline from the Stairs power plant farther up the canyon. When originally constructed, water was carried from the Stairs plant to the Granite plant by way of a 9000+ foot wooden conduit or flume. That flume terminated at the upper end of a 1200 foot metal penstock (A round riveted steel pipe that is still visible on the hillside above the power plant.)

Without getting to technical, the 450 foot drop in elevation along the 1200 foot length of the penstock created tremendous pressure at the nozzle or "head" of the pipe, and would spin the cup shaped Pelton-wheels at incredible speeds, thus turning the generators.  

Though no longer in use, it is worth noting that a smaller side pipe of the penstock drove a smaller Pelton-wheel that turned a belt-drive system, providing mechanical power to a lathe and drill press in the main powerhouse.  

The Granite plant is very small by todays standards, but was state of the art when originally constructed. The plant is still in use, and is now part of the Pacificorp / Utah Power system.

Reworked and upgraded regularly on the inside, the outside of the Granite powerhouse still retains much of its 1896 appearance with it's arched doors and windows, fancy brick-work, sandstone nameplate, original wood trim paint color, and decorative yet functional star shaped tie-rod anchors or "Earthquake bolts" as they are sometimes called.

The buildings and site were listed on the U.S. Department of Interior's National Register of Historic Places in 1989.

Getting there

Direct access to the site is not possible. For security reasons it is completely fenced and gated. However, the site is easily visible from the Big Cottonwood Canyon highway, near the mouth of the canyon, on the north side, directly above the Salt Lake County Water Treatment Plant.

What remains

The powerhouse, transformer house, original operators house, and the long metal penstock are all present at the site, all relics from the original construction. Other garages and outbuildings from more recent times are present on the site as well.
View of the Transformer house is somewhat obstructed, but the main powerhouse is clearly visible, so too, portions of the penstock, rising up the hillside to the east of the plant.


Carved sandstone nameplate above the powerplant's double doors - c.2011 / Donald K. Winegar - Tintic Images


Detail of the buildings exterior showing the arched windows, intricate brickwork , and the decorative "Earthquake bolts" - c.2011 / Donald K. Winegar - Tintic Images


(1) Utah Power & Light - National Register of Historic Places Registration Form - NPS Form 10-900 - OMB No. 1024-0018, March, 1989 -