Courier staff writer
VALLEY — Tri-State Generation and Transmission Association, Inc. is now looking south to increase electric reliability in the Valley.
On Monday morning, San Luis Valley Rural Electric Cooperative (SLVREC) CEO Loren Howard shared the details of the company’s alternative route interest with the San Luis Valley County Commissioners Association during its regular meeting.
He said after Exel Energy pulled out of the Colorado Public Utilities Commission approved joint transmission project to move power from the Valley to Walsenburg and then north to the Comanche power plant, Tri-State has since looked at the alternatives and decided to move forward to research a possible connection with the Carson transmission line in New Mexico.
“It is important for us to focus on our transmission capacity in the Valley,” Howard said. “If something happens, we want geographical diversity... You don’t want all of your eggs in one basket.”
Today, the Valley’s main source of energy comes from the north, he said. There are three lines, two major and one much smaller. The proposed San Luis Valley/Carson line would accommodate 230 kV and would start somewhere near the Alamosa and Conejos County border and finish near Española, N.M.
“The east was cheaper,” Howard said. “But this will give us more geographic diversity.”
He said the project would first undergo a NEPA assessment, which sets production back a few years.
Growth in residential and agricultural loads throughout the Valley has caused the existing transmission infrastructure to reach its capacity, according to a Jan. 14 Tri-State press release. Tri-State studied several options to meet the electric reliability needs, including generation and demand management options, before identifying new transmission infrastructure as the most cost-effective and highest benefit to electric consumers.
The alternative project will meet Tri-State’s goal of bolstering reliability of the electric grid, with the added benefit of supporting potential renewable energy development, according to the press release.
“Tri-State remains committed to making the necessary infrastructure investments to ensure a reliable power supply to the farms, ranches, and communities of southern Colorado,” said Joel Bladow, Tri-State’s senior vice president of transmission in the press release. “Tri-State will study the alternative through an open, transparent and responsive process that incorporates public input and a rigorous environmental review.”
The project will help ensure reliable power to SLV REC, which serves more than 7,500 member owners in a network of more than 3,100 miles across the Valley.
“We are pleased that Tri-State remains committed to ensure our co-op can continue to provide reliable power to our member-owners across the Valley,” Howard said. “We look forward to working together with Tri-State and the San Luis Valley community to ensure the project is a success.”
Tri-State is a wholesale power provider owned by 44 cooperatives including SLV REC. Tri-State owns about 5,200 high voltage transmission lines in its four-state network and serves about 1.5 million customers.
In the mid 1990s, Tri-State conducted studies identifying reliability concerns with the main 230 kV line crossing Poncha Pass into the Valley, specifically what might happen to the Valley should that line fail.
The company has taken many interim measures such as replacing transformers and installing capacitor banks, but even with those improvements, the company continues to have concerns about reliability. The back-up line for the 230 kV line is a 115 kV line, but that smaller line has a threshold of 65 megawatts, and the load in the Valley often exceeds that. In 2004, for example, the Valley exceeded that 65-megawatt threshold 20 percent of the time.
The peak season for electrical use in the Valley is during the irrigation season, but even the “shoulder” seasons are seeing increased power usage. In 1997, the non-irrigation season months averaged around 30 megawatts versus 2011 when the shoulder months averaged 50 megawatts, much closer to that 65-megawatt threshold that the backup line could not meet if the main power line over Poncha was lost.
Based on the studies and the need to provide more reliable power, a project was proposed to construct a new 230 kV line from Walsenburg into the Valley, and in 2008, Tri-State and Public Service signed a memorandum of agreement to pursue this joint project. In May 2009 the companies submitted a Certificate of Public Convenience and Necessity (CPCN) application to the Colorado Public Utilities Commission (PUC), which approved the CPCN in September 2011.
In October 2011, Trinchera, which owns property where the line would cross, filed an appeal to the CPCN in both Denver and Costilla County, and that appeal is pending.
In the same month, Public Service announced it would likely end its involvement in the project.
Valley Courier editor Ruth Heide contributed to this article.