Intermountain Project of the Year, Best Energy/Industrial, Excellence in Safety: Olmsted Hydroelectric Power Plant
Olmsted Hydroelectric Power Plant
Best Project, Energy/Industrial
Owner: Central Utah Water Conservancy District
Government Agency: U.S. Bureau of Reclamation
Lead Design Firm & Structural, Civil, MEP Engineer: Jacobs Engineering Group
General Contractor: Ames Construction
Hydroelectric Equipment Supplier: Andritz Hydro
Subcontractors: Coblaco Services Inc.; Canyon Hydro; Envision Mechanical Inc.; KG/Unlimited Steel; Raymond Keller Construction; TY Steel LLC; United Team Mechanical
Located at the mouth of Provo Canyon in Orem, Olmsted is one of the oldest hydropower generation plants in the Western U.S. Hydroelectric power generation originally began more than four miles up the canyon in 1897, when L.L. Nunn and the Telluride Power Co. operated the first high-voltage (44,000 volts), long-distance (32 miles), alternating-current power transmission system in the world. Increasing power demands forced the plant to move down to the mouth of the canyon in 1904, where it has operated almost continuously since.
A 2010 evaluation showed the facility nearing the end of its life, and the plant shut down temporarily in September 2015. Preliminary design for a new facility was already underway because continuous operation of the plant is critical to maintaining Olmsted’s water rights.
The plant replacement included construction of a new powerhouse and a new transmission line, lining a 12-ft rock tunnel with 84-in. steel pipeline and installing more than 600 ft of 84-in. buried penstock.
Building a new hydroelectric power plant at the mouth of an isolated canyon with challenging site constraints was no easy task. “Water rights was the common denominator, and we knew it was essential,” says K.C. Shaw, chief engineer at Central Utah Water Conservancy District, operator of the federal facility.
The team set up a two-day partnering exercise to establish a path for successful execution. Much of the specialized, owner-procured equipment had to be ordered from overseas. “We had to design the plant around the equipment,” says Adam Murdock, engineer-of-record for Jacobs. Predesign was finalized after turbines and generators were selected, with some final reconciliation occurring after the general contractor, Ames Construction, came on board.
The new powerhouse needed to be built next to the existing one and very close the Provo River, which required extensive dewatering in order to excavate down to 45 ft. During construction, numerous historic artifacts were discovered. “Working around historic conditions was not new to us,” says Brandon Evans, project manager with Ames. “We were careful to ensure [archaeological] specialists were there to observe the handling and catalog the artifacts,” he says, thus preserving them for inclusion in a future museum at the old powerhouse.
Much of the pipeline construction occurred during the winter on slope ratios reaching up to 1.75:1. Crews used two excavators working in tandem to move and install 20-ft sections of penstock, each weighing 22,000 lb.
“Then we had to backfill and restore the slope,” Evans says. This resulted in a big visual improvement, since the older, exposed penstocks were in bad shape. “Today, you’d never know there is 84-in. penstock there,” Shaw says.
The installation of 850 ft of 84-in.-dia, welded-steel pipe into a 12-ft rock tunnel was another challenge. Because of the limited access, the team engineered and fabricated two steel-pipe carriers on railcar wheels that would hoist and carry the pipeline into the rock tunnel on rails. Work in the tunnel required continuous air testing and full-time observation to monitor and maintain strict access to the hazardous location. The project logged more than 250,000 work hours with zero recordables.
“This was a huge accomplishment for such a high-risk project,” says Evans, noting that the restricted site with steep slopes, deep excavations and high-voltage overhead power lines also had no laydown area and required the use of large cranes and heavy equipment in difficult weather conditions.
Power production at the new Olmsted plant began in 2018. “We were able to install a very efficient, high-quality, modern plant and deliver a project that continues the legacy of a historic generation of power,” Shaw says.