Caballero Energy Storage Project
The Caballero Energy Storage Project is a 99.7 MW/ 400-megawatt hour (MWh) Battery Energy Storage System (BESS) located in Nipomo, California, providing flexible energy storage capacity by allowing for storage and dispatch of clean, renewable energy, increasing the reliability of the California grid.
Completed in late 2024, and in its final stages of testing, the Caballero BESS Energy Storage Project will provide enough energy to power more than 100,000 homes for up to four hours daily during peak electrical demand. Caballero BESS will store clean solar energy during midday hours and discharge that energy when most needed. This provides grid reliability to San Luis Obispo County and the California Independent System Operator (CAISO) market.
What is a
Battery Energy Storage System (BESS)?
Battery Energy Storage Systems, known as BESS, are a proven technology, delivering unmatched grid reliability capabilities while enabling the transition to clean energy. Currently, around 21 Gigawatts (GW) of commercially operational BESS are deployed across the United States. That is enough clean energy to power more than 20 million homes during peak demand periods.
BESS projects use the same core technology as the battery powering the phone in your pocket but on a much larger scale. Similar to charging your phone while you sleep, BESS systems like Caballero efficiently and conveniently capture electricity, storing it to be used when needed most.
On its most basic level, a battery is a device consisting of electrochemical cells converting stored chemical energy into electrical energy. A grid-connected BESS consists of batteries, racks for the batteries, inverters converting DC energy to AC energy, communications equipment allowing complete control and constant monitoring of the batteries, as well as equipment ensuring safe, optimal battery operation. These components and battery systems are housed in specially designed and engineered enclosures.
In recent years, advances in technology and novel materials have greatly increased the safety, reliability, and efficiency of modern battery systems like Caballero BESS.
How does this project
benefit the community?
Battery Energy Storage System (BESS) projects like Caballero are essential in the transition to a clean and reliable grid, especially with the planned retirement of the Diablo Canyon nuclear power plant in the near future. Caballero BESS guarantees a reliable supply of power even during peak demand. In addition to storing and supplying clean, resilient solar energy to Californians, Caballero BESS provides:
Up to 146,000 MWh
per year of excess unused solar energy, captured then restored to the grid in peak time
60 Local Jobs
during the height of construction, as well as onsite technicans to maintain and operate the facility
Powering 100,000+ Homes
for up to four hours daily during periods of peak electrical demand
$1.5 Million
per year in local tax revenue on average over the next 10 years
What measures are in place to ensure
the project is safe?
Caballero BESS incorporates the latest and most advanced technology and safety standards to date. Caballero development benefited from two decades of hands-on working experience with lithium-ion batteries. Lithium-ion batteries are a radically improved technology in contrast with certain legacy systems that are known to present fire risks.
The project was built and tested by some of the nation’s leading design & construction companies. The electrical site work was performed entirely by IBEW-trained personnel to ensure the highest standards of safety and quality are achieved.
Working in close coordination with the San Luis Obispo County Fire Department, the project was put through rigorous testing to meet all of the latest applicable codes and standards. This includes all applicable BESS tests and standards (NFPA 855, 69, 72, 70, UL 9540, UL9540a, UL1973, IEEE 485).
Per the code, the project has developed an Emergency Response Plan and performed first responder training as a result. The plan reviews all the possible failure modes, including the very least likely, and trains operators and responders for safe handling.
Caballero BESS has proven that no scenario would constitute a threat to the lives or the property of those living nearby.
Caballero BESS was designed adhering to the latest standards, with Cal Fire adding a layer of site-specific requirements. Caballero BESS was then audited, inspected, and witness-tested by San Luis Obispo County Fire and Cal Fire on all of the systems on-site, which include:
Early detection systems
Fire Control Command Center at site
Auto shutoff systems
Active Overpressure Mitigation System (NFPA 69)
Water available at site for protection
Direct Cal Fire alarm system
24-7 site monitoring
24-7 fire alarm monitoring
Battery Energy Storage Systems
Frequently Asked Questions
Who is Alpha Omega Power?
Alpha Omega Power (AOP) is a utility-scale renewable energy developer, owner, and operator based out of Houston. Alpha Omega Power supports the full spectrum of battery storage development and operations, including power market analysis, site prospecting, strategic siting and permitting, pre-construction, Engineering, Procurement and Construction (EPC), as well as commercial operations. AOP is committed to deployment and oversight throughout the project life, from inception to operations and eventual decommissioning. AOP solutions enhance grid reliability, support renewable energy integration, and contribute to a cleaner, sustainable energy future.
What is Alpha Omega Power's Safety Record?
Alpha Omega Power’s (AOP) team of skilled professionals possesses decades of power and battery industry expertise and experience. AOP uniquely understands our evolving power grid needs and commits to deploying the safest, novel technologies for all AOP Battery Energy Storage System (BESS) facilities.
Who is Fengate?
Fengate Asset Management (Fengate) is a leading investment management firm partnering with Alpha Omega Power (AOP) to finance Caballero Battery Energy Storage System (BESS), acquiring the project from Origis Energy in 2024. Fengate is a leading alternative investment manager focused on infrastructure, private equity, and real estate strategies, with more than US$7 billion of capital commitments under management.
Why Battery Storage?
Simply put, Battery Energy Storage Systems (BESS) allow energy to be safely stored for times when it is needed. As California and the United States continue the transition to a clean and reliable grid, a BESS is essential in guaranteeing a reliable supply of power, even during times of peak demand.
BESS can also deliver lower costs for businesses and households while reducing carbon emissions.
Is Battery Storage Safe?
Yes. Battery Energy Storage Systems (BESS) are extremely safe.
According to the U.S. Energy Information Administration, currently, there is approximately 21 Gigawatts (GW) of commercially operational battery capacity deployed in the U.S, up from 1 GW just four years ago, and that number is expected to reach 30 GW by the end of 2025.
The Caballero BESS project is fully compliant with extremely restrictive fire codes that were developed by the National Fire Protection Association (NFPA) in 2020 and 2023. NFPA 855 is the benchmark for all projects in this field and includes extremely well-documented, fact-based requirements for Energy Storage. Caballero BESS meets NFPA 855 code requirements and goes above and beyond those requirements in many areas that the Alpha Omega Power (AOP) team and Cal Fire officials found important for public safety.
While there have been fire incidents at older energy storage facilities, these occurrences are very rare. The design and technology of BESS systems have evolved tremendously in the past few years, and the industry’s approach to safety has advanced in tandem. Most notably, the adoption of NFPA 855 and UL9540 standards. UL9540 is the American and Canadian National Safety Standard for Energy Storage Systems and Equipment. These are a few of the safety measures and design improvements implemented at Caballero BESS.
Is There a Risk of Fire?
Incidents have occurred in the last decade involving lithium-ion Battery Energy Storage Systems (BESS). The National Fire Protection Association assembled an expert team under its standard 855. The first version of NFPA 855 was published in 2020 and continues evolving with over 25 of the nation’s best experts contributing to put an end to BESS fire hazards. Since the 2020 NFPA release, no BESS fire has caused any injury or third-party property damage in the U.S.
The Caballero BESS project has been through rigorous tests to meet all the latest applicable codes and standards, working in close coordination with the San Luis Obispo County Fire Department. Caballero BESS incorporates today’s most advanced technology and safety standards and is proven to be safe and reliable. This includes all applicable BESS tests and standards (NFPA 855, 69, 72, 70, UL 9540, UL9540a, UL1973, IEEE 485).
Caballero BESS complies with NFPA 855 and with additional requirements beyond the code as required by San Luis Obispo County and the Cal Fire Departments. The BESS used at Caballero has been exposed to:
- Lithium-ion cell ignition tests to verify that an internal electrical or chemical malfunction caused fire (“thermal runaway”) will not propagate to create a full block fire.
- A torching test at the unit level to verify that fire does not propagate should a major external fire occur.
The batteries have demonstrated very low flammability, and Cal Fire approved their use at Caballero BESS. Cal Fire rigorously reviewed all documentation with the help of a renowned NFPA 855 expert.
The project was built and tested by some of the nation’s leading design & construction companies. The electrical site work was performed entirely by IBEW personnel, ensuring the highest standard of safety and quality was achieved.
Caballero BESS was designed to adhere to and exceed the latest local, state, and federal standards. Cal Fire added a layer of site-specific requirements, then audited, inspected, and witness-tested all the systems, which include:
- Early detection systems
- Auto shutoff systems
- Fire Control Command Center at site
- Active overpressure mitigation system (NFPA 69)
- Water available at site for protection
- Direct Cal Fire alarm system
- 24-7 site monitoring
- 24-7 fire alarm monitoring
Caballero BESS is equipped with advanced safety monitoring 24/7 with management systems to ensure that any potential risks associated with the installation and operation of the battery system are addressed and mitigated. This includes fire suppression at the individual battery cell level and active ventilation to prevent the buildup of combustible gases within the enclosure.
What about the Recent Battery Fire in Northern California? Can that Happen Here?
The utility-scale Battery Energy Storage System (BESS) technology used today looks and operates very differently from the technology used just a few years ago. Caballero BESS incorporates today’s most advanced technology and safety standards and underwent rigorous testing to meet or exceed all the latest applicable codes and standards. Alpha Omega Power (AOP) provided proof of working safety systems in close coordination with the San Luis Obispo County Fire Department.
Caballero BESS is distinctly different from older battery storage sites for two key reasons:
1. Caballero BESS battery cells are an intrinsically safer technology and far less flammable than legacy technologies used in 2015-2018 era projects. Caballero BESS uses only the latest technology, Lithium Iron Phosphate (LFP) batteries, at the facility. LFP features the highest-rated safety metrics and performance, far superior to the older, less stable models.
2. Caballero BESS incorporates an entirely different design approach than the one in Northern California, which was built within a legacy energy plant. The trend now is toward the containerization of battery systems inside large units similar to shipping containers. Containers minimize the risk of fire spreading to nearby batteries – which happened at Moss Landing and Otay Mesa – and can be constructed to include explosion prevention and fire suppression technologies. At the Moss Landing and Otay Mesa sites, the companies placed all their outdated LG batteries together in one building without installing adequate fire sensors or suppression equipment. Caballero BESS utilizes separate, module battery containers, each with its own batteries, which are continually monitored with sensors, controls, and safety equipment inside. This means that in the very unlikely event that an incident does occur, it will be suppressed inside that individual container and unable to spread or affect any neighboring units.
Has Caballero BESS Fully Passed Cal Fire Tests?
Alpha Omega Power (AOP) is working closely with the San Luis Obispo County and City Fire Departments, and the site underwent testing for each battery container on the property. Lithium-ion batteries demonstrate extremely low flammability. Ignition tests were conducted to verify and prove that an internal electrical or chemical malfunction will not propagate to create a full block fire. Conversely, a torching test for an external fire, like a brush fire, verified that it would not spread inside the containers.
Cal Fire approved the use of lithium-ion batteries at the Caballero Battery Energy Storage System (BESS) and tested every single unit on the property to make sure they are in compliance with National Fire Protection Association (NFPA) Code 69, verifying the venting system will dissipate any dangerous gas in the unlikely event there is a fire.
Caballero BESS was designed and built using NFPA 855 safety measures, which did not exist for the older battery storage facility that caught fire at Moss Landing. For comparison, Caballero BESS uses different batteries, contained storage units, with 24/7 monitoring, sensors, and fire suppression, and adheres to the newest regulations.
Is Deflagration a Risk?
No. Deflagration has been known to happen in cases of unmitigated thermal runaway in Battery Energy Storage Systems (BESS) housed in buildings. The Caballero BESS project is entirely outside, and all units are thoroughly tested to stop thermal runaway rapidly. In addition, they comply with National Fire Protection Association (NFPA) Code 69, and Cal Fire has tested every unit to verify that its venting system will dissipate any dangerous gas in the unlikely case of a thermal runaway.
What about Soil or Air Pollution?
Caballero batteries are tested against propagation. No possible scenario or even a combination of scenarios at this location can create a fire of the magnitude Moss Landing experienced. In the very worst scenarios, as in an entire battery container fully engulfed in flames, our plume analysis showed that the smoke would be below toxicity levels at a distance of 110 feet from the center of the fire. This scenario is nearly impossible given all the National Fire Protection Association (NFPA) 855 safety measures. Of note, NFPA 855 did not exist at the time Moss Landing was constructed.
We are also tracking rigorous environmental monitoring and comprehensive studies conducted by organizations like the New York State Energy Research and Development Authority (NYSERDA). These studies have consistently demonstrated that previous fire incidents involving Battery Energy Storage Systems (BESS) have not posed a significant risk to public health. The risk of modern BESS fires is said to be comparable to other common risks, such as residential fires. In line with this research, various officials who spoke at a February 12, 2025, press conference on the Moss Landing fire reported that:
- Monitoring by U.S. EPA found levels of particulate matter and hydrofluoric acid posed no risk to the public.
- The Department of Toxic Substance Control found no soil contamination.
- Monterey Bay Air Quality District detected no impacts associated directly.
More questions? We have the answers.
The project team at Alpha Omega Power welcomes questions about the Caballero BESS project.
Please contact us via email: [email protected] or by calling 805-316-0145.
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