One of the questions that opponents keep asking during meetings about the Diamond Tail solar project is why it is being located in the East Mountains rather than in the Four Corners, especially as it is being billed as a way to replace coal-fired generation.
The developers of the project say they chose the location because it is close to population centers and can be connected to the grid at the new Diamond Tail substation just a short distance away.
But nearby residents say while they like the idea of solar and battery storage, the location is wrong because of limited firefighting resources, proximity to a scenic byway and other factors.
San Juan County, however, has a history of embracing large-scale solar and battery projects.
Mike Eisenfeld, energy and climate manager for San Juan Citizens Alliance, said San Juan County has the advantage of abundant lands that aren’t close to residential areas.
But those lands, if they are not privately owned, may come with extra permitting steps that the Diamond Tail solar project doesn’t need.
The Diamond Tail Ranch is fully private property, which cuts out the need for an environmental analysis under the National Environmental Policy Act.
Meanwhile, many of the solar projects underway in San Juan County are at least partially on federal lands or tribal lands. This means they generally need environmental assessments, and some may even need the more intensive environmental impact statement.
At the same time, Diamond Tail also faces one permitting hurdle the projects in San Juan County don’t face: zoning.
Before the project can move forward, PCR U.S. Investments, the developer, must have the Sandoval County Commission approve a zone change. The closest thing San Juan County has to zoning is a business registration ordinance that was passed so first responders would know if there were any hazardous materials at a site.
Eisenfeld said the projects in San Juan County don’t tend to garner the opposition projects like Rancho Viejo near Santa Fe or Diamond Tail have experienced.
This is in part because projects can be built on already disturbed land in areas without a lot of nearby houses. The San Juan Solar Project essentially abuts the underground San Juan Coal Mine, and the access road was once used to haul coal to the power plant from the now-reclaimed La Plata Mine. The private property has been used for energy leasing in the past, though its main use was cattle grazing.
“A lot of these solar projects … that have run into problems, it’s because they’re in proximity to where people live,” Eisenfeld said.
The electricity from the San Juan Generating Station has already been replaced
The New Mexico Public Regulation Commission approved replacing the electricity the Public Service Company of New Mexico received from the San Juan Generating Station with renewable resources, primarily in the form of solar and battery storage. These projects are already largely completed.
Earlier this month, PNM, the developer Clēnera and 150 megawatts of four-hour battery storage capacity celebrated a ribbon cutting for one of them. The Atrisco solar and battery storage project in Bernalillo County provides more than 300 megawatts to PNM customers. This is far bigger than the proposed Diamond Tail solar project.
The only remaining coal-fired power plant in New Mexico is the Four Corners Power Plant, which is scheduled to close in 2031 and only operates on a seasonal basis. This power plant is located on Navajo Nation land across the San Juan River from the San Juan Generating Station.
The Navajo Transitional Energy Company, which owns the adjacent Navajo Mine and part of the Four Corners Power Plant, has been exploring options for energy resources at the site, including potentially updating the power plant with carbon capture technology or building solar on the reclaimed mine site.
There are projects underway near the coal-fired power plants
Utilities across New Mexico are not only looking to replace fossil fuel generation, they also need to build out more capacity to meet the growing demand for energy. This is in part due to a push for electrification, including more electric vehicles.
Developers began eyeing San Juan County as a location for new solar generation as soon as PNM announced the power plant would close. Without the coal-fired generation sending electricity down the transmission lines to Albuquerque and Santa Fe or even to Arizona, solar and battery project developers saw opportunities.
Photosol U.S. was one of the developers who began working on projects, including the San Juan Solar Project, that replaced some of the generation from the shuttered power plant. During public meetings, Photosol officials said they specifically chose sites near closing power plants to build arrays. Ultimately, Photosol sold the San Juan Solar Project and it was completed by D.E. Shaw Renewable Industries (DESRI).
The San Juan Solar Project is currently similar in size to the proposed Diamond Tail solar project, but it could increase in size in the future.
PNM was not the only utility that received electricity from the San Juan Generating Station. Los Alamos County’s publicly-owned utility owned a share of the power plant and has an existing agreement with PNM to use transmission infrastructure.
In February, Los Alamos County signed an agreement with DESRI for what is known as Foxtail Flats. Foxtail Flats is in the same area as the San Juan Solar Project and will provide Los Alamos County with 170 megawatts of solar power and 80 megawatts of battery storage. It is expected to debut online in 2026.
Because Los Alamos has a county-owned utility, it does not fall under the requirements of the Energy Transition Act.
PNM also has plans for new solar and battery storage in the Four Corners area, including a new utility-owned solar array.
Building on BLM lands can be challenging
When the Shiprock Solar Project in San Juan County entered the permitting process in 2020, the BLM had a single solar energy zone (SEZ) in New Mexico where solar projects could be developed without needing a hard-to-obtain variance. That SEZ was located south of Las Cruces.
Because the Shiprock Solar Project was fully on BLM lands, it required the variance.
The U.S. Bureau of Land Management released its new Western Solar Plan earlier this year, which opened 31 million acres of federal lands across 11 states to solar development.
The newly updated Western Solar Plan allows developers to consider locations within 15 miles of existing or proposed transmission lines. However, BLM lands with a high likelihood of having sensitive wildlife or cultural resources are excluded from development.
“The updated Western Solar Plan is a responsible, pragmatic strategy for developing solar energy on our nation’s public lands that supports national clean energy goals and long-term national energy security,” BLM Director Tracy Stone-Manning said in a statement when announcing the update. “It will drive responsible solar development to locations with fewer potential conflicts while helping the nation transition to a clean energy economy, furthering the BLM’s mission to sustain the health, diversity and productivity of public lands for the use and enjoyment of present and future generations.”
The San Juan Solar Project did need to have lines crossing federal lands, which required an environmental assessment. However, since the project itself was on private lands, it did not require a variance.
Eisenfeld said the Shiprock Solar Project may end up being a “litmus test” for what happens with projects on federal lands in San Juan County. While the BLM planning website lists it as canceled, Eisenfeld said developers are still pitching the project.
The transmission in the Four Corners may need upgrades
PNM released a transmission plan earlier this year that looks 20 years into the future.
As more renewable energy comes online in different parts of the state, PNM will need to make investments into transmission infrastructure. The transmission plan outlines the steps PNM needs to take to reach its goals of 100 percent carbon-free energy by 2040.
While new renewable resources are being built, PNM’s natural gas generation assets will be retired. PNM will need to spread out resources so if the weather impacts generation in one area, there will still be electricity from other parts of the state.
Limitations on how much electricity current transmission infrastructure can conduct will also impact how many projects can be built in San Juan County.
“There’s only so many projects that are going to be able to tie into existing transmission,” Eisenfeld said. “The bigger question around here is going to become new transmission.”