THERE are two consistent threads in comments submitted to the Colorado Public Utilities Commission around its investigation into solar energy and transmission development in the San Luis Valley.
The first is that the Valley’s sun is perfectly suitable for renewable solar energy and the cost to develop it is as low as it has ever been. The second is that transmitting the solar energy and sharing it with the rest of Colorado is the challenge due to the difficulty of establishing new transmission routes in the mountainous region.
“The SLV is generally regarded as having the best solar resource in Colorado, and among the best in the United States. The Valley’s flat, high-elevation geography and dry and sunny climate is conducive to large-scale solar developments,” Public Service Company of Colorado told the CPUC in February.
“In fact,” according to comments relayed by the Interwest Energy Alliance and Western Resource Advocates, “the National Renewable Energy Laboratory (NREL) identified the Valley as the premier site for Concentrated Solar Power (CSP) siting in the state of Colorado.”
The background
Last November the Colorado Public Utilities Commission opened a miscellaneous docket proceeding to look at the potential value in a new transmission solution into and out of the San Luis Valley. Then in December the CPUC board agreed to move forward with an investigatory proceeding to “examine alternative options for expanding transmission capacity within the San Luis Valley.”
The state regulatory agency has not signaled any additional steps since it closed its comment period in February on solar and transmission development in the San Luis Valley. The Colorado Public Utilities Commission will get a new director following the retirement of Doug Dean and the timing of when it proceeds with its San Luis Valley review is unclear.
‘Part of it is solar irradiance’
It’s the output of light energy from the entire disk of the Sun – or solar irradiance – that makes the sun in the Valley suitable for solar energy development. “It is imperative that this potential resource is not hampered by lack of transmission,” the Interwest Energy Alliance and Western Resource Advocates said in their joint comments.
“Larger transmission interconnection to the rest of Colorado and the wider western interconnect could have profound implications for job growth and diversification in the SLV as well,” they noted.
The Colorado Energy Office is also on board with solar and transmission development in the Valley. In comments to the CPUC, Colorado Energy Office said it is working through the U.S. Department of Energy to help secure funding for transmission development. The DOE, as part of the Bipartisan Infrastructure Law, announced a $10.5 billion investment to strengthen the electric grid in the United States through its Grid Resilience and Innovation Partnerships Program.
“Additional capacity will enable connecting new solar resources to the grid that can help advance the state’s transition to clean, renewable energy,” the Colorado Energy Office offered in its comments. “Additionally, the construction of transmission lines and the subsequent construction of solar facilities in the SLV would provide substantial economic benefits to a portion of the state that has historically had lower economic growth.”
Comments to the Colorado Public Utilities Commission note the ongoing reduction of irrigated agriculture as San Luis Valley farmers come into compliance with the state’s groundwater pumping rules and work to restore the aquifers of the Upper Rio Grande.
“By having a robust transmission system, landowners will have an alternative to put their property to good use and help create jobs for the area,” Monte Vista City Manager Gigi Dennis wrote in her comments to the CPUC. “And in considering water scarcity in Colorado and from the Rio Grande River, valuable land will be put to beneficial use with solar farms rather than a crop that is thirsty for water. This is good conservation.”
“The cards are all lined up to go ‘Colorado has this expectation of being carbon-free, so does Tri-State, so does Xcel, and you have this resource here, we just don’t have any place to go with it.”
– state Sen. Cleave Simpson
Transmission challenge
In a 2022 report, the National Renewable Energy Laboratory in Golden notes, “The cost of solar power in the Valley compares favorably to utilities’ current and recent historical costs” but that the market demand for a solar project is uncertain given the regulatory process.
“Many alternatives exist in Colorado that can serve the same demand at the same cost but with fewer transmission limitations. The game-changing factor would be a decision by Xcel Energy and the Tri-State Generation and Transmission Association to upgrade the 230kV line from the Valley to Poncha Springs, Colorado, which would add as much as 600 MW of new export capacity, or four times the solar capacity currently in the Valley.”
In comments to the CPUC, Public Service said “many factors have changed over the past decade that merit a thorough reconsideration of new investments transmission to unlock the Valley’s solar resources. Increasing cost-effectiveness of new renewable resources, load growth, the state and federal policies that promote or require carbon emissions reduction from electric generation required another paradigm shift in planning for the expansion of the transmission system.”
Identifying new transmission routes to match solar energy generation is separate from the ongoing work Xcel Energy is doing in upgrading the existing transmission system in the Valley through major line rebuilds. Public Service said it will invest around $115 million in modernizing the Valley’s transmission system, including an upcoming replacement of the Alamosa to Antonito transmission line.
There are three transmission lines that connect the Valley to Colorado’s transmission grid, Public Service notes. These three lines all begin in Poncha Springs in Chaffee County and enter the northern edge of the Valley over the 9,010-foot elevation Poncha Pass. “Today, transmission service to the Valley is radial in nature – the system is connected to the electric grid from one location and is not networked with other parts of the Public Service or neighboring transmission systems through a separate path.”
“The National Renewable Energy Laboratory identified the Valley as the premier site for Concentrated Solar Power siting in the state of Colorado.”
– Interwest Energy Alliance and Western Resource Advocates
Public Service, Tri-State Generation and Transmission Association, the U.S. Department of Energy (DOE) and the Bureau of Land Management have all studied alternative transmission routes in the San Luis Valley. More than a decade ago, Public Service and Tri-State gained approval from the Colorado Public Utilities Commission to develop an approximately 95-mile “Calumet transmission line” on the eastern edge of the Valley but ran into concerns from private landowners, including Trinchera Ranch owner Louis Bacon.
Ultimately, following a legal challenge in Costilla County District Court, Public Service and Tri-State officially bowed out of the project. Blanca Ranch Holding, LLC and Trinchera Ranch Holdings, LLC have filed a notice of participation with Colorado Public Utilities Commission for the next round of discussions on where to site new transmission routes in the Valley.
“Transmission expansion in the SLV will require sustained attention and political capital by a broad variety of stakeholders and will entail the coordination of resources to solve challenges with reliability, technology, geography and land use, wildfire risk, and cost,” Public Service said in its comments.
As Tri-State notes, routing challenges exist along all five of the state highways out of the Valley: Highway 160 over Wolf Creek; Highway 114 over North Pass; Highway 285 north over Poncha Pass; Highway 160 east over La Veta Pass; and Highway 285 south toward New Mexico.
“Routing challenges exist along each of these highways as they each run through (or near) land held by the Bureau of Land Management (BLM), US Forest Service, National Park Service, Fish and Wildlife Service, Bureau of Reclamation, and Bureau of Indians Lands. Further, some land is subject to a conservation easement (in the case of Trinchera and Blanca Ranch), is part of a National Park (Great Sand Dunes), or is part of a National Monument (Rio Grande del Norte).”
And therein lies the challenge: The San Luis Valley has the sun to generate solar energy as a redundant source of power for itself and to share with the rest of the state. Transmitting it is where the problems begin.
TOP PHOTO: A solar farm off CO 17 in Alamosa County.
by Owen Woods.
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