Revitalizing Estes-to-Flatiron infrastructure

To modernize its aging power infrastructure, WAPA is embarking on a transformative project that will replace a pair of high voltage transmission lines that have served hydroelectric generation plants and Colorado’s historic town of Estes Park for nearly 100 years. The decision to replace these lines comes after years of proactive maintenance and observation by WAPA and the Bureau of Reclamation, highlighting the need for improved safety, reliability and reduced fire potential.

In 1938, Reclamation constructed the Estes-to-Lyons 115-kilovolt transmission line. Its primary purpose was to provide power for the ambitious Colorado-Big Thompson, or CBT, facilities project, which aimed to collect water from the Western Slope and upper reaches of the Colorado River and distribute it throughout the state’s Front Range communities. This ambitious endeavor sought to address the water needs of the growing population centers on the plains, which then, as it does now, accounted for 80% of Colorado’s inhabitants.

Currents of change

As the CBT project progressed, completing the 13-mile-long Alva B. Adams Tunnel in 1947 marked a significant milestone. This tunnel facilitated the passage of water from west of the Continental Divide to the east slope, harnessing the potential energy and converting it into electrical energy through hydroelectric generators along the water’s flow path. To support this hydroelectric generation and provide power to Estes Park and surrounding areas, the Estes-to-Pole Hill and Pole Hill-to-Flatiron 115-kV transmission segments were added in 1953 with the addition of the Pole Hill Powerplant, completing the two parallel 15-mile transmission lines between Estes Park and Loveland.

However, the original wooden H-frame transmission line structures, which were expected to have a lifespan of 40 years, defied expectations due to the proactive maintenance techniques and dry climate of the Northern Colorado mountains. These transmission lines and structures continued to operate well beyond their expected lifespan, but in recent years the need for a comprehensive upgrade became evident.

Greg Johnson, an electrical engineer from the Rocky Mountain region, who has been the Estes-Flatiron project manager since 2014, emphasized the safety aspect of the project.

“Double circuit steel poles greatly reduce the amount of maintenance required compared to 80-year-old wood pole structures,” Johnson said.

He further highlighted the benefits of consolidating the two rights-of-way onto a single one, reducing the maintenance distance by half and improving vegetation management strategies to ensure reliability, safety and reduced fire risk.

Infrastructure modernization for a resilient future

The decision to replace the aging wood structures with modern steel poles was driven by the need to conform to North American Electric Reliability Corporation reliability standards and minimize the risk of wildfires.

Johnson explained, “Wildfire has two components: the risk of the transmission line initiating a fire and risk to the transmission line from fire. The combination of old wood-pole transmission lines, reactive vegetation management practices and narrow ROW increase vulnerability to wildfire.”

“Alternatives that utilize steel pole structures, wider ROW and active vegetation management greatly reduce the risk of damage from wildfires and the risk of initiating wildfires,” he added.

The Estes-to-Flatiron transmission lines rebuild project, initiated in 2009, focuses on replacing the aging wood-pole lines that were increasingly at risk of failure. The project aims to reduce the maintenance burden, resolve access difficulties and reduce lifecycle costs. It involved extensive public outreach and engagement, with scoping meetings and a public comment period to ensure transparency and gather community input.

Standardizing the conductor size, collaborating on fiber-optic communications infrastructure and prioritizing long-term maintenance costs were crucial steps in ensuring a reliable power supply and meeting the region’s evolving needs. While the original infrastructure had served Estes Park community and Reclamation generation well, the criticality of electrical supply, loads and fiber communications had increased exponentially in the past 80 years, necessitating the upgrade.

The project, which covers federal, state and private lands, is currently 60% complete and should be in service by the end of the year. Ultimately, aging and deteriorating transmission lines will be replaced, reducing potential disruption for customers due to wildfire hazards, improving access for maintenance and emergencies, and ensuring that the transmission lines comply with applicable codes and requirements.

Note: The author is a public affairs specialist.