DMEA makes good on 100-year-old hydro plan

A unique hydroelectric project that was envisioned by the U.S. Bureau of Reclamation more than a century ago when the 6-mile Gunnison Tunnel was completed as part of a vast irrigation system in western Colorado’s Uncompahgre Valley, is now a reality thanks to Tri-State member Delta-Montrose Electric Association (Montrose, Colo.) and its project partner, the Uncompahgre Valley Water Users Association.

More than 100 years ago the completion of the Gunnison Tunnel was a major engineering feat that was acclaimed by President Taft.

More than 100 years ago the completion of the Gunnison Tunnel was a major engineering feat that was acclaimed by President Taft.

The opening of the Gunnison Tunnel in 1909 was hailed as a major engineering feat at the time, attracting dignitaries, noted newspaper media and even President Taft, who traveled to Colorado to officially dedicate the project.

The tunnel, bored through the walls of the Black Canyon as a water diversion from the Gunnison River, served as the capstone of a 575-mile network of canals and ditches which irrigate the many farms and ranches of the Uncompahgre Valley.

Although the new water supply network was considered a boon to the region’s agriculture industry, it was quickly noted by the media and the bureau’s engineers that a secondary benefit of this irrigation system could be to harness the fast-moving water to generate low-cost electricity to light the farms and small towns across the valley.

This unique fish gate at the mouth of the Gunnison Tunnel uses electrodes in the water to create a low voltage electrical field that deters fish – without harming them – from entering the canal system.

This unique fish gate at the mouth of the Gunnison Tunnel uses electrodes in the water to create a low voltage electrical field that deters fish – without harming them – from entering the canal system.

Fast-forward 100 years to 2009. Although a number of studies on the potential of hydropower on the  Uncompahgre Valley canal system were conducted over the years, it wasn’t until a century later, in 2009, that an agreement was finally reached between DMEA and the water users group to develop the $22 million South Canal Hydroelectric Project about five miles outside of Montrose.

DMEA secured 100 percent funding for the project utilizing Clean Renewable Energy Bonds that are made available to electric co-ops, municipalities and other not-for-profit entities at a very favorable interest rate, according to Jim Heneghan, the co-op’s renewable energy engineer.

DMEA engineer Jim Heneghan explains the South Canal hydro project at the site 1 diversion inlet.

DMEA engineer Jim Heneghan explains the South Canal hydro project at the site 1 diversion inlet.

Construction took place during 2012 and 2013, and the second of the project’s two units began commercial operation on Aug. 1.

The physical hydroplant was designed to take advantage of the existing irrigation network with a few modifications. Once the water diverted from the Gunnison River travels through the Gunnison Tunnel, it enters the South Canal, a main artery of the irrigation supply system.

On the South Canal, a concrete diversion structure was built that parallels the existing canal and channels water into an intake system known as site 1. From there, the water enters an underground pressurized pipe known as a penstock.

At site 1 the water travels nearly a quarter of a mile, dropping a total of 55 feet until it reaches the power house. Inside the power house is the stator/generator and below it the turbine, where up to four megawatts of electricity are produced.

Downstream from the power house is the tail race, where the water re-enters the South Canal. A short distance downstream from site 1 is an almost identical facility referred to as site 3, which produces up to 3.5 megawatts of power during optimum conditions.

The stator/generator inside the power house at site 1 of the South Canal hydro project.

The stator/generator inside the power house at site 1 of the South Canal hydro project.

The DMEA engineer noted that they are currently in the preliminary design phase for a potential site 2 on the South Canal, which could produce and additional three-fourths of a megawatt.

In addition to holding 50 percent ownership in the project, DMEA is also the operator of the facility, which is achieved remotely from the co-op’s dispatch center in Montrose.

The operation of the South Canal Hydroelectric Project is tied to the irrigation season. In October, the Gunnison Tunnel will shut down and so will the hydroplant, until the growing season begins again the next spring.

“We are very pleased with this project,” Heneghan said. “Let’s hope it doesn’t take another hundred years to build more hydro facilities on this system.”

Tri-State is a supporter of South Canal Hydroelectric Project and dozens of other successful member-sponsored local renewable projects. As such, the association’s board provides financial incentives to encourage renewable facilities, which now add up to nearly 50 megawatts of combined generation output across the member service territory.

0 Responses to “DMEA makes good on 100-year-old hydro plan”


  • No Comments

Leave a Reply




%d bloggers like this: