What does it mean for an energy storage system to be “smart”? And how does it help energy storage owners and operators maximize the lifetime value of their assets? At Fluence, “smart” is more than a label; it is a design philosophy that shapes how we engineer, deploy, and operate our storage systems. That thinking drives Smartstack™, our next-generation, high-density energy storage platform, created to meet the evolving demands of companies developing and operating grid-scale storage assets.
Smartstack brings together three core elements that define “smart” at scale: high energy density, a modular architecture that separates battery pods from power controls, and embedded intelligence that enhances performance, safety, and reliability over time. In this blog, we explore how these features work together to make Smartstack a future-ready solution.
Re-Imagined Design for Density
Over the last few years, density has become a driving concern in our industry. With site sizes increasingly tipping above 1 GWh, storage owners ask: how can I squeeze the footprint of my site without sacrificing cost or deployment time? Our answer is a reimagined, AC-based platform that uses vertical space more efficiently by separating key system components into stacked, modular units. Smartstack delivers up to 30% higher energy density than current market alternatives—without sacrificing safety or reliability.
At just 32,000 square feet (3,000 square meters) for a typical 100 MW/400 MWh project, Smartstack packs more energy in smaller spaces. Its flexible duration configurations (2-, 4-, 6-, and 8-hour options) enable developers to tailor storage solutions to specific market applications, without overbuilding or under-delivering.
A New Modular Structure for Battery Pods and Power Controls
By separating the system into two core components—the Smart Skid and modular battery pods—we created a serviceable, scalable design that simplifies and speeds up installation and lowers total cost of ownership. The Smart Skid forms the intelligent foundation of the system, integrating advanced cooling, power control, and monitoring hardware with easy maintenance access. Stacked above are interchangeable Pods, engineered to support multiple cell vendors and allow for rapid upgrades or servicing. This modularity not only makes the system easier to transport and install, with split components that reduce shipping constraints and simplify onsite assembly, but also opens up new flexibility in augmentation planning, allowing customers to upgrade battery technologies over time without replacing the entire system. In turn, the system can evolve with performance, longevity, and regulatory needs.
Powered by Intelligent Performance
Smartstack was designed from the outset to deliver analytics at the edge, powered by the enhanced capabilities of the Fluence OS. Sensor density has been significantly increased throughout the system, down to the cell level, along with onboard computing power and data bandwidth. As a result, Smartstack can conduct faster, more precise analyses and respond in real time to optimize performance, safety, and reliability.
Fluence OS and the Battery Management System (BMS) work together to automate essential maintenance tasks while minimizing operational disruption. These enhancements improve state of charge (SOC) accuracy and reduce outages or power reductions during recalibration. Smartstack can identify system areas requiring recalibration and perform targeted adjustments during normal operation, while giving operators visibility and control over the processes when needed.
Fluence OS also enables real-time system health monitoring and autonomous issue resolution. When a cell-level imbalance is detected, passive balance resistors in the BMS activate automatically to address the condition. This reduces energy loss, extends asset life, and allows operators to participate more effectively in energy markets.
Smartstack's Embedded Intelligence
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These capabilities are further supported by Fluence Nispera™, our advanced asset performance management software. While Fluence OS operates within the system, Nispera delivers fleet-level insights that enhance operational decisions and long-term planning. Drawing on a global dataset that includes both Fluence and third-party systems, Nispera continuously refines its models to detect anomalies, forecast degradation, and optimize dispatch strategies.
Included with every Smartstack system, Nispera’s BESS Advanced Analytics monitor key performance indicators such as state of health (SoH) and state of balance (SoB). These insights help operators shift from reactive to predictive maintenance and proactively manage system performance and availability.
The combination of Fluence OS and Nispera forms an intelligent digital backbone that strengthens every Smartstack deployment. Real-world insights, such as minor performance deviations during commissioning, inform ongoing refinements to BMS algorithms and hardware. This integrated intelligence ensures Smartstack continues to evolve, becoming more responsive and capable over time.
A Smarter Solution for an Evolving Market
The global energy storage market is growing and changing rapidly, with BloombergNEF projecting a 35% increase in additions this year—reaching a record 247 GWh. As the market expands and project footprints grow, so does the focus on accelerated profitability—and with it, the criticality of density, speed, and intelligent performance.
Smartstack was created with these pressures in mind. Now available for sale globally, with deliveries beginning in late 2025 and U.S. domestic content available starting in mid-2026, Smartstack’s design and embedded intelligence open up a smarter path to portfolio returns.
When the stakes are high and projects are scaling fast, you need the smartest energy storage solution available. You need Smartstack.
Ready to unlock value with Smartstack?
Contact us to learn how Smartstack can solve your unique energy challenges, with intelligence built into every layer.
