Reducing Execution Risk in Energy Storage with VaultOS™ EMS and Real-Time Plant Digital Twin

Missed Commercial Operation Dates (CODs) are costing energy storage projects millions and continue to happen more often than they should. According to ERCOT Energy Storage Interconnection Queue data, projects miss COD by an average of seven months, with Energization to COD taking an average of five months. Every delay means mounting costs, including fielded teams, idle equipment, and accumulating loan interest, with no revenue to offset expenses. In a market where time is money, Energy Vault’s VaultOS™ Energy Management System (EMS) and Real-Time Plant Digital Twin provides a compelling option to dramatically reduce commissioning risks. By identifying risks and neutralizing them before commissioning starts, our software accelerates deployment, minimizes downtime, and ensures projects go-live on schedule and within budget.

Energy storage projects often exceed $100 million in investment. Batteries, inverters, and EPC (Engineering, Procurement, and Construction) costs accumulate rapidly, and every idle day translates to lost revenue. Projects can miss COD due to permitting delays, construction setbacks, equipment failures, controls, and integration issues. While many factors contribute to commissioning risks, this article focuses on reducing execution risk utilizing VaultOS™ EMS, the system that ties all equipment together at site.

The Challenge: Integration Complexity and Late-Stage Discovery

On most projects, the first time all equipment is tested as a complete system is during on-site commissioning, when the COD clock is ticking. Complex interactions in power plant controls often remain undiscovered until commissioning begins, leading to unexpected delays.

Traditional Factory Acceptance Tests (FATs) validate individual hardware components before they leave the factory, but do not account for full-system integration of batteries, inverters, transformers, and grid infrastructure. Many critical issues only surface during onsite commissioning, making fixes expensive and time-consuming.

Power systems modeling tools like PSS/E and PSCAD simulate power response and inverter behavior and are critical to the development of a robust Power Plant Controller (PPC). They focus primarily on the inverters and the PPC response to the grid, but they don't easily facilitate testing of the implementation of the complete hardware and software system at site. They fail to capture battery behavior, cooling systems, safety mechanisms, and real-world plant dynamics. Leaving pre-commissioning testing of the project incomplete results in a fragmented approach with unforeseen issues that drive-up costs and delay project timelines when discovered at site. PPC controls modeled in PSS/E and PSCAD are often not cross-validated with production software or equipment allowing for discrepancies between simulation and actual controls in the field. These are critical tools but don’t fully test the control system end-to-end in real-time.

The Energy Vault Approach: VaultOS™ and Speed Through Simulation

VaultOS™ is Energy Vault's Power Plant Controller and Energy Management System, providing real-time monitoring, operational control, and optimized dispatch for energy storage and generation assets. VaultOS™ controls everything at an energy storage site, from monitoring individual cells to full-scale power dispatch. As a hardware-agnostic solution, it integrates with any inverter, battery, or balance-of-plant equipment (sensors, HVAC, chillers, fire protection systems). Managing extensive onsite equipment requires high-resolution data down to the battery cell level. On projects with hundreds of thousands of cells, this can involve handling millions of data points per second, a topic we’ll explore in an upcoming blog post.

The cost of late-stage discoveries is staggering. Delays can mean millions in lost revenue and penalties. To solve this, we designed and built VaultOS™ to de-risk project execution. Our solution: VaultOS™ Real-Time Plant Digital Twin, a patented software-based platform that creates a full virtual replica of an energy storage site to enable full end-to-end testing of the PPC and EMS software with simulated site equipment months or even years prior to deployment. The software tested in our simulation is “byte for byte” identical to the fielded software. The software runs in real-time as if it’s talking to fielded equipment during the simulation.

VaultOS™ isn’t just a concept—it has already proven its value in large-scale projects. On our first large-scale deployment, the Stanton Battery Energy Storage System (SBES), a 68.8 MW / 275.2 MWh project with Wellhead Electric in Stanton, CA. Hal Dittmer, Chief Executive Officer of Wellhead, highlighted our speed:

“The Energy Vault team designed and deployed the optimal energy storage solution for our Stanton site,” said Hal Dittmer, Chief Executive Officer, Wellhead. “Only a few days after mechanical completion the system delivered full power to the grid validating the quality of the design and execution. Energy Vault did an excellent job of providing a solution that met both the challenging energy density requirements and the equipment delivery time frames to enable the project to go forward. We are a satisfied customer, and we appreciate Energy Vault’s expertise, creative thinking, and collaborative partnership in bringing this project to fruition.”

For our first project, we achieved full power to the grid in just a few days and reached COD within weeks when most projects take much longer. How did we move so quickly? We started early! We identified and addressed power plant control risks before the equipment was powered on for the first time. Everything was tested in a Real-Time Plant Digital Twin before we set foot onsite, allowing us to troubleshoot and resolve potential issues before they could delay COD. Performance testing begins months in advance, providing ample time to address challenges proactively. When we ran through each of the site performance tests in Stanton, we knew exactly how that plant would respond and knew we would run reliably once we went into the market. The project ultimately was called upon and went into the market early providing critical assistance during a Southern California heat wave in the summer of 2023.

Lessons from Aerospace to Energy Storage

Our software team at Energy Vault is a mix of engineers with expertise in many industries including energy storage, software development, aerospace & defense, cybersecurity, IoT, and telecommunications. We took lessons learned across multiple industries to build a new energy storage software controls platform for the next generation of multi-GWh systems.

Currently, I lead the software engineering and development of the VaultOS Energy Management System, but my background in aerospace and defense involved developing and deploying systems for ships, airplanes, and UAVs, systems that must perform flawlessly in mission-critical environments. My previous team couldn’t always take our platforms for a spin to test our equipment whenever required. Digital simulation technology was essential because real-world testing was not often an option. Since we couldn't always field test these systems before they ran in operational environments, we developed rigorous test harnesses and simulations to evaluate both the equipment and the software in high-fidelity simulated environments.

At Energy Vault, we adapted these methodologies to energy storage, applying advanced modeling and real-time simulation to improve efficiency, mitigate risks, and ensure a seamless transition from construction to operation.

What is a Real-Time Plant Digital Twin?

Energy Vault's Real-Time Plant Digital Twin is a high-fidelity virtual model of an energy storage system that integrates real-world data, advanced simulation algorithms, and predictive analytics. This model replicates the performance and interactions of batteries, inverters, and grid components, enabling us to identify and address issues long before deployment.

Key Benefits of VaultOS™ Real-Time Plant Digital Twin

- Accelerate Commissioning and Reduce Risk: By simulating system performance in software, we shorten commissioning time and ensure on-time COD. Common integration issues that typically arise in the field are resolved before deployment.

- Protect High CAPEX Investments: Energy storage systems involve many pieces of equipment from transformers to cells. We monitor and control all site equipment. Even medium-sized sites can involve hundreds of thousands of cells, each with critical voltage and temperature parameters. Our solution ensures all assets are monitored and safely controlled for long-term reliability and optimized return on investment.

- Create High-Fidelity Site Models: We build digital representations of entire sites, capturing how batteries, inverters, transformers, and grid connections interact under real operating conditions. By testing in real-world environments, we refine our models and ensure future projects benefit from lessons learned. It also makes for a pretty cool demo!

- Minimize Deployment Disruptions: Through predictive simulations, we resolve performance and control issues before they happen, ensuring smooth, uninterrupted commissioning and operation. We create real-time fault scenarios, observe system responses, and compare them to actual site behavior, allowing us to refine models and controls quickly based on real-world data.

- Test Model for Commissioning, Operations, and Augmentation: The digital twin provides an environment for allowing issues to be replicated and changes tested during commissioning and operations. This reduces time to diagnose issues and provide a better Operations and Maintenance (O&M) experience for our clients. Also, these models can assist in the augmentation process and test the controls of the site before augmentation occurs limiting any potential conflicts or downtime.

Proven Impact

The impact of VaultOS™ EMS and Real-Time Plant Digital Twin was essential to our early success on our first Gigawatt-hour of projects. By resolving integration and operational issues before allowing them to become field problems, we have reduced commissioning times, lowered costs, and improved system reliability. Our customers benefit from faster time to market, fewer unexpected delays, and confidence that their energy storage systems will perform as designed from day one.

As energy storage projects grow in scale and complexity, VaultOS™ EMS and Real-Time Plant Digital Twin will be an essential tool in reducing execution risks and ensuring seamless deployment. With continued advancements in analytics, machine learning, and real-time data integration, we are setting new industry standards for speed and reliability.

We have put this to the test on our latest project, the Calistoga Microgrid, the world’s largest green hydrogen-powered microgrid. This system integrates advanced energy storage and hydrogen fuel cells to provide resilient backup power. While the physical site is nearing mechanical completion, our virtual simulation has been operational for over a year. By leveraging our Real-Time Plant Digital Twin, we rigorously tested microgrid controls well before the first hydrogen delivery, ensuring seamless integration, optimized performance, and risk mitigation ahead of commissioning.

At Energy Vault, we’re not just building energy storage systems, we’re transforming how they are deployed. Our technology ensures projects hit their COD targets, maximize return on investment, and operate reliably from day one. VaultOS™ EMS and Real-Time Plant Digital Twin isn’t just a battery controller, it’s the key to energy storage project success.

COD delays cost millions. VaultOS™ eliminates risks and ensures your project goes live on time and on budget. Stay tuned for more in our next blog post on battery cell monitoring and more.

Shaheen Fakhar is the VP of Software Engineering and Development at Energy Vault and leads the development of VaultOS. Previously, he led software development teams at Boeing and Argon ST, where he spent nearly 20 years as a software engineer and leader developing mission-critical systems. Shaheen has a BS in Computer Science from Penn State University.