Last Revised April 23, 2024

The following information comes from the AES Corporation directly and the permit application they have submitted to the county, or from our consultations with experts. Other sources are noted.

The AES Corporation has applied to the Santa Fe County for a permit to build a Utility-Scale solar and battery facility called the “Rancho Viejo Solar Project” encompassing 688 – 1,000 acres (over one square mile). They plan to include 205,712 solar panels, and some 38, 40-foot battery containers housing over 570,000 lithium-ion battery cells to store over 141 megawatts of power. (We believe this is the largest battery facility proposed so far in the state of New Mexico.) They also intend to erect a 2.5 mile, 50-foot high-voltage power line to a new 2-acre substation to connect into the PNM grid.  According to their permit request, once the facility is built, there will be no personnel on site at this industrial installation. It will be monitored remotely. (Note numbers differ from their January 2023 application to the County, see link.) https://www.santafecountynm.gov/growth-management/building-development/large-scale-renewable-energy-projects-2023


They plan to site this facility approximately one mile east of Highway 14, just above the community of Rancho San Marcos, just west of Eldorado, and south of Rancho Viejo, (see map below). In other words, this industrial facility will be in the immediate vicinity of over 10,000 homes and more than 25,000 residents in those three communities as well as four schools: the Santa Fe Community College, the Institute of American Indian Arts, the Turquoise Trail Charter School, and the Eldorado Community School. With so much available land and brownfields (https://en.wikipedia.org/wiki/Brownfield_land) in our state we don’t understand why our officials are even considering this location. Did you know that there are no solar projects with or without batteries over 50MW located anywhere near residential properties in New Mexico? Here’s is a link to the Global Energy Monitor to use to confirm this. https://globalenergymonitor.org/projects/global-solar-power-tracker/tracker-map/

There are a number of concerns with a project of this size and complexity, first and foremost of which is fire from the batteries.

“Lithium-ion batteries are prone to overheating, swelling, electrolyte leakage venting, fires, smoke and explosions in worst case scenarios involving thermal runaway. Gases produced as a result of a fire, smoke and/or thermal runaway can accumulate to a combustible level in the installation location and cause an explosion.”– “Battery Hazards for Large Energy Storage Systems” by Judith A Jeevarajan   https://pubs.acs.org/doi/full/10.1021/acsenergylett.2c01400

The primary cause of an energy storage system fire is caused by having a battery cell go into thermal runaway. During thermal runaway, the heat generated within the battery cell exceeds its ability to dissipate. When this occurs, the battery cell can cause adjacent battery cells to overheat, potentially driving them into thermal runaway. If this chain reaction occurs across multiple battery cells, it can spread from modules to the rack and result in a significant fire.” and “During a thermal runaway event, heat inside the battery can also cause the battery’s electrolyte to evaporate out of the battery cell, creating a mixture of volatile gases that can explode if the battery system is not properly vented.” – “Mitigating Thermal Runaway Risks and Lithium-ion Battery Fires” by Chris Wright https://www.cea3.com/cea-blog/mitigating-thermal-runaway-risks-and-lithium-ion-battery-fires

According to a recent article in the NY Times, brush fires are now more prevalent and destroy more homes than forest fires. https://www.nytimes.com/2023/11/09/climate/forest-fires-grasslands.html?smid=nytcore-ios-share&referringSource=articleShare

Since the fire chiefs in Santa Fe city, county and state acknowledge that the single biggest threat we face out here are wildfires, the question then becomes is it wise to site a known source of fires in the middle of so many residential communities surrounded by all the grasses and trees in that area, otherwise known as Wilderness-Urban Interface or WUI. https://www.usfa.fema.gov/wui/

The U.S. Department of Energy defines four main types of solar projects, see page 16 in their “Solar Power In Your Community, A Guide for local governments….”  https://www.energy.gov/sites/default/files/2023-03/Solar_Power_in_Your_Community_Guidebook_March2023.pdf

Residential: Also referred to as “rooftop solar”, residential solar is a form of distributed energy with solar panels mounted on individual rooftops. Residential solar deployments can range in size from 3 kW – 11kW.

Commercial: Commercial solar is a larger form of distributed solar energy that encompasses rooftop and ground-mounted deployment. Commercial solar deployments can range in size from 100 kW – 2 MW.

Community: Also referred to as “solar gardens” or “shared solar”, community solar is another form of distributed energy where customers can buy or lease a portion of an off-site shared solar project. Community solar sites are typically <5 MW in size.

Utility-Scale: Utility-scale solar deployments are ground-mounted systems that feed the generated electricity directly into the electric grid. Utility-scale solar deployments can range in size from 5 – 100 MW.

*Note these MW references are for generating power, not battery storage.

We believe the AES Rancho Viejo Solar Project, which proposes generating 96 MW of power, is not Commercial Solar, but rather a Utility-Scale project, and thus should not be allowed a Conditional Use Permit (CUP), but instead be reviewed as a Development of County Wide Impact (DCI) which allows for more review and oversight.

Since state or local laws may define solar sizes differently, we also looked at the Santa Fe County Sustainable Land Development Code (SLDC). It references that a Conditional Use Permit (CUP) may apply in some zoned areas for Commercial Solar, however we could not find any reference to Utility-Scale Solar. See Santa Fe County Sustainable Land Development Code 2016:  https://www.santafecountynm.gov/media/files/SLDC%201.20.17.pdf

Lithium-ion battery fires are not like normal fires as they are, in fact, a chemical reaction which produce their own source of oxygen and so cannot be extinguished by any conventional means such as water or foam. These fires also release highly toxic hydrofluoric acid, cyanide and other gases that can explode upon ignition and often require a “shelter in place order “or an evacuation of surrounding areas.  (During the AES battery fires in Arizona, the other industrial facilities around those fires were evacuated).  https://www.fema.gov/case-study/emerging-hazards-battery-energy-storage-system-fires

As a result of the difficulty in extinguishing such fires, the standard firefighting procedure is to now let the batteries burn out by themselves – a process that can require days or even weeks in some instances. Lithium-ion battery fires can also appear to be out and then reignite later so the facility must be monitored closely during and after a fire. “In this case the safest thing to do for everyone involved is to allow it to burn itself out,” said Orange County Fire Coordinator, (see link). https://westchester.news12.com/fire-at-battery-storage-facility-burns-off-combustible-material

At present, our local firefighters say they do not have the expertise or equipment to deal with large, toxic, chemical fires.

There are fire suppression systems inside the battery containers, which require a chemical called Novec 1230. Novec 1230 is the branded name of this chemical by the 3M company who has announced they will stop manufacturing Novec 1230 by the end of 2025 because it contains PFAs which are otherwise known as “forever chemicals”. 



PFAs are man-made, toxic chemicals that have been detected in both food and water.  https://www.atsdr.cdc.gov/pfas/health-effects/exposure.html

3M was recently fined $10.3 billion for polluting waterways with Novec 1230, and the money from that fine is to build water treatment plants to try and remove the toxic chemical from the municipal water supplies.  However, there is no way to remove these chemicals from groundwater, aquifers, or wells. 



AES says it plans to use a chemical called FK-5-1-12 in their fire suppression system.  This is the exact same chemical as Novec 1230.  They also claim that “based on independent assessment, this chemical poses no threat to the environment.”  As of yet, AES has not provided who this third-party assessment was done by. Nor do we know where or to what extent their particular fire suppression system has been used or tested. And the fact remains that, even with fire suppression systems, these battery containers can still catch fire.

Yes. In April of 2019 an AES battery storage facility in Surprise, Arizona caught fire and subsequently exploded which seriously injured several firefighters. https://www.12news.com/article/news/local/valley/faulty-battery-system-triggered-explosion-that-injured-surprise-firefighters-last-year-report-finds/75-b1f2d532-ef81-4fdc-855d-e8e2a32b6350

And again, in April of 2020, another AES battery storage facility caught fire in Chandler, Arizona. https://www.fox10phoenix.com/news/lithium-battery-storage-facility-fire-chandler

Both of those facilities were a fraction of the size of the one they are proposing here in Santa Fe County(AZ: 2.6 MW and 10 MW. Here in Santa Fe County they are planning between 141MW – 200MW of battery storage.)  

Both of those Arizona battery facilities were sited in Industrial Zones—not residential areas– and the surrounding industrial facilities were evacuated as a result of the toxic smoke during those fires.

A Battery Safety Science webinar overview of the 2019 Surprise AZ thermal runaway incident, the investigation’s contributing factors, and recommendations for the fire service, code officials, utility companies, and manufacturers to prevent similar incidents. See Youtube: Fire Service Considerations investigations of AZ LI-ion ESS incident. https://www.youtube.com/watch?v=mn9irm8djdM

A good link to research other battery failures nationally and worldwide is the “BESS Failure Event Database”. https://storagewiki.epri.com/index.php/BESS_Failure_Event_Database

Note: If you go to this website, we found it helpful to change the “Show 10 entries” to 50 and to double click on the arrow to the right of “Location” so it’s set downward which will bring the US entries high on the list. You will see “US, AZ, Chandler,” and “US, AZ, Surprise” on their list)

Almost all solar facilities have some form of minimal battery backup to maintain the operation of the solar facility, such as to supply the motors that may turn the solar panels or to monitor the flow of power from the solar cells.  The size of such batteries is comparable to, say, the battery from an electric vehicle if even that big.

But not all solar installations, even those on an industrial scale, have battery storage systems, which are known as BESS (Battery Energy Storage Systems).  Indeed, AES’ own website says “…today almost half of our new projects include a storage component.”  Which means that more than half of their new projects do not include a battery component.

In the Environmental Impact Report that AES submitted to the county with their application, it mentions “an optional BESS” (page 2-1)   So it is not required for a solar project facility to have a battery storage component at the same location.  

For the Rancho Viejo Solar Project here, AES says the solar part will generate 96 Megawatts of electric power.  All of that power could go directly onto the grid. So, then the question becomes, why does AES want to construct a massive BESS that can store 141-200 Megawatts?

5 Myths about BESS:  https://www.bakerrisk.com/news/myths-battery-energy-storage-systems/#:~:text=Myth%20%235%3A%20Structures%20containing%20BESS,when%20battery%20cells%20become%20compromised

From our research and consultation with numerous electrical engineers, the reason AES wants such a large battery facility is that it will offer them the opportunity to not only store the energy from their solar panels, but to pull energy off the PNM grid when demand is low, and then sell it back to PNM or even other out of state users when rates go up and demand is high.  In public hearings, AES’ own experts have confirmed this is their intent.

It is our understanding that this is how they can make the most profit in a process known as ‘arbitrage’ or ‘wheeling’.  The profits from this would far exceed any profit they could make from the power generated by the solar panels themselves.  https://www.investopedia.com/terms/a/arbitrage.asph

Hence, the larger the battery facility, the more they can store and sell, and the more money they can make by ‘wheeling’ in the electric energy marketplace, since that power can be sold to Arizona, California, or other states where the cost of electric power is higher than it is here.  All of which has no direct benefit to the citizens of New Mexico.

Average cost of electricity in the U.S. is 12.36 cents per kW.

The cost in New Mexico is 10.02 cents per kW.

The cost in California is 22.33 cents per kW.

If you compare the cost of electricity at https://www.eia.gov/electricity/state/ you can see why this would be a beneficial business model.

So, just because this large battery facility is located here, with all the attendant risks of these battery installations, doesn’t mean that our rates will be any lower.

In our direct meetings with both county and state officials, it was clear that AES had not informed them this was their intended business plan.  All those officials were under the impression that the “need” for these batteries was to just store the power from the solar panels, not to pull and push power on and off the PNM grid to maximize AES’ profits.

This revelation raised a number of concerns.

AES had not been fully honest or forthcoming with the county or state about their reasons for wanting this facility.

If the real value to AES was not the solar generation but a massive battery facility, which presumably they could even expand over time, was this really a renewable energy project at all?  Or was it instead a battery project with solar generation tacked on to make it appear environmentally ‘positive’ to garner official and public support?  A technique known as “green washing”.

To prevent the County from releasing information to a citizen, AES sued the County and obtained a Temporary Restraining Order forbidding the County from sharing any negative information.  AES did not want the public to know the percent of likelihood that a thermal runaway would occur, nor what toxic gasses would be released by the battery cells they intend to use.  AES did not want to reveal where they intended to site this facility.   AES claimed the information, such as facility location, were "trade secrets."

 If AES’ goals for this project were transparent, why would they need a court order to prevent the public from knowing what exactly they intended to build?

Did you know that AES has maintained that this project’s design is 10% and 30% completed?  They continue to be refining their design as they develop the project, hence the numbers continue to change.

And, while we appreciate AES moving into renewable energies, we are seriously concerned by their history and lack of concern for the effect their projects have had on local communities. See “Lawsuit accuses Virginia power company of poisoning Dominican community with toxic coal ash” https://www.facingsouth.org

From 2000 to 2021 AES was fined over 30 million dollars for environment, employment, competition, and safety offenses in the US, see link to the Violation Tracker Good Jobs First. This does not take into consideration their projects overseas. https://violationtracker.goodjobsfirst.org/parent/aes-corp

With today’s technology Battery Energy Storage Systems (BESS) come with risks that require considerable planning and preparation. htttps://www.travelers.com/resources/business-industries/energy/battery-storage-system-advancements

What do homeowners need to know about the AES Project?

AES has submitted a report done by a firm they hired that concludes the property values of nearby communities will not be affected.

We dispute that finding and all the real estate experts we’ve contacted to date find that conclusion inaccurate in the extreme.  We are planning with the funds we raise to pay for a new and independent report regarding the effect of this installation on local property values.

Many if not most of the homeowners in the nearby communities consider their homes to be their largest, single asset.  So, if there proves to be a significant impact on property values to nearby communities the economic effect to local residents could prove to be considerably damaging.

As we have all seen across the country recently, because of climate change, insurers are becoming increasingly reluctant to offer affordable homeowner’s insurance and, in many areas, withdrawing the sale of insurance coverage altogether.  Santa Fe and its surrounding communities are no longer immune from these considerations.  There are already anecdotal reports that homeowners in the forested areas along Hyde Park Road to the ski basin, will not have access to insurance when they sell those homes to new owners.

Given that wildfires are the principal danger to properties in our area, one can only assume that, with the known fire hazards associated with BESS installations, if it is constructed as planned, insurance rates in the area will increase if it remains available to local communities at all.

Here again, we hope to use the funds we raise to hire insurance experts to ascertain if this is the case.

If as a result of the AES project, property values go down and insurance rates go up, who will compensate homeowners for that?  Will it be AES?  Will it be the county if they approve this project?  Or will homeowners simply have to bear those costs while AES reaps almost all the profit from this project?  Note: The taxes AES says they will be paying to the county are $200,000 a year.  This would not even cover the replacement of one home.


Are there other hazards or consequences about the AES Project I should know?

There is a major natural gas pipeline that runs north-south along the western edge of Eldorado and up past the Santa Fe Community College.  These gas lines come above ground in places in what are known as “regulator stations”.  These exposed regulators are immediately adjacent to both Eldorado and the Community College. That is, some of these exposed lines are within approximately one mile from the proposed AES facility.

In our ongoing communications with the New Mexico Gas Company, their representatives have confirmed that, should a wildfire reach those exposed lines, there is a high risk that a gas explosion would occur.  And could extend into all the homes in Eldorado and other communities that currently use natural gas.

In their permit application, AES has requested between 32 – 49 million gallons of water to construct the facility, and 650,000 – 1 million gallons per year to operate it. None of the engineers we’ve consulted can explain why AES needs such extraordinary water resources. Nor does AES’s application explain their need since the “fire suppression systems” they intend to use require toxic PFAs or ‘forever’ chemicals, not water.

Though the current AES Environmental Impact Report (EIR) that was submitted with their application does not specify where this water will come from, in our direct communications with AES, they have said water will not come from any existing wells on the property nor will its construction partners drill any new wells. The source for all this water is now listed as the following or a combination thereof:

Santa Fe County Bulk water station commercial pipe water,

Ranchland Utility Company Class A reclaimed water,

Santa Fe County reclaimed water,

Or any other legally permitted commercial water sales.

It is not yet been made clear how any or all the water from the sources listed above will get to the site.  And we will wait to see if, in their revised EIR which has yet to be submitted to the county, their claims for either the amount of water or its sources conform to the statement above. 

Because of the toxic fumes from a BESS fire, we don’t know how far people should be directed to shelter in place or evacuate. “Residents within a one-mile radius of the fire at the Convergent Energy facility in Lyme, NY were directed to shelter in place…”  https://www.wwnytv.com/2023/07/28/convergent-offers-words-apology-solar-farm-fire-continues-burn/

“Some of the products of combustion from thermal events may be considered hazardous. This is true for BESS installations, as well as most other fires. It is important to understand the specific hazards for each installation, which will allow a safe perimeter to be established during a thermal event. This perimeter will protect emergency responders without creating undue shelter in place warnings.” https://pv-magazine-usa.com/2023/11/10/bess-thermal-events-what-to-know-and-what-to-expect/ 

Concerned moms at “Moms Clean Air Force” discuss how chemical and toxic fires affect air quality and health. https://www.momscleanairforce.org/fires-chemicals-toxic-pollution/#:~:text=Wildfires%20and%20Chemicals&text=These%20noxious%20chemicals%20and%20heavy,health%20of%20people%20long%2Dterm.

We do know that a toxic plume could blow in any direction. And when we met with emergency responders in Santa Fe, we were told it’s not a good idea to have an evacuation plan that might direct people towards a fire rather than away from it. Instead, they recommend preparing your own personal “Ready, Set Go!” wildfire action plan. Here’s a link to their free booklet. https://www.santafecountynm.gov/media/files/SantaFeRSGGuide2017.pdf 

The lithium-ion battery containers require external cooling systems in addition to the internal fire suppression systems.  According to AES, each of those cooling systems produces 70 decibels of sound or noise.  As they have requested 38, 40-foot such containers, the total noise produced would be 85 decibels.  This is equivalent to the noise level on a typical street in a major metropolitan city. Except here, certainly during the spring and summer months, that noise would be produced 24 hours per day.   Depending on both the ambient air temperature and the wind, it is difficult to calculate exactly how far that noise would carry and how many residences would be affected.

This of course does not account for the noise produced during the approximate one or so years it will require to construct the facility.

AES application says they plan to build a 40 – 50’ tall, high-voltage power line that will run 2.4 miles to a new PNM Substation just above the northwest corner of Eldorado.  When we requested more details, AES confirmed the H-frames for the transmission lines will be 50 feet tall and the structural span was increased from 250 feet to 376 feet. There will be 31 H-frames covering what they say will be a 2 to 3-mile transmission line.

We believe this new transmission line should be buried so as not to affect the wilderness landscape.

The AES application states that they will have no personnel on the site during its operation but will “monitor it remotely” – they do not specify who will be “monitoring” this facility or where they may be located.  Nor do they include how long it would take for these ‘monitors’ to contact local firefighters in the event that one of their battery containers bursts into flames or explodes.

We also don’t know if they have plans for regular maintenance of the facility. How will they prevent weeds, brush, and tumble weeds from accumulating if there’s no personnel on site. Who will provide oversight to assure safety precautions are maintained during the life of this facility?

Given the size and scope of this proposed installation, which is over a mile on every side, with security fencing around the entire installation, and includes over 200,000 solar panels, motion-sensor security lights and noise from the cooling systems, we can assume the impact on the local wildlife will be substantial. For more detailed information on exactly which animals will be most affected, you can go to:  https://www.nmresponsible.com/wildlife-impact

You can also visit The Nature Conservancy site where you can access the tool “Energy Sprawl Solutions” https://www.nature.org/en-us/what-we-do/our-insights/perspectives/energy-sprawl-solutions/ . You’ll find articles like “Meeting Global Clean Energy Goals Starts Local: How State Officials are Balancing Energy Needs and Wildlife.”  https://www.nature.org/en-us/what-we-do/our-insights/perspectives/energy-wildlife-scarlett-loveless-qa/

AES refers to the approximate 1-year construction period as a “temporary condition.”

The TRAFFIC STUDY prepared by AES’ consultants Bohannan Huston lists the following:

“10 heavy haul trucks (ex: wheeler deliveries, water trucks, garbage trucks) per day”

“75 to 150 work trucks (ex: crew, foreman, superintendents) per day”

“40 work trucks specifically for the BESS (Battery Energy Storage System) install per day”

“It is anticipated that 190 work trucks will arrive between 6:30 am and 7 am and will depart the site at 4pm.” *

“The ten heavy trucks will arrive outside the anticipated peak hours.”

* The hours listed conflict with the hours in their Environmental Impact Report.

Their ENVIRONMENTAL IMPACT REPORT states the following:

(page 2-3) “Contractors commuting to the Project will generate approximately 115 to 190 trips per day for the duration of the construction period, for a total of 29,900 to 49,400 trips.”

(page 2-4) “Typical construction work schedules are expected to be 7:00 am to 7:00 pm Monday through Friday, with the potential to work on Saturday.”

For those who regularly use Highway 14 south of Santa Fe to and from the city, the addition of all these construction vehicles, if accurate, will likely cause persistent delays.

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