The energy storage industry is at an inflection point. For decades, project-finance models and OEM warranties have treated 20 years or 60 percent remaining capacity as the practical end-of-life for a battery energy-storage system (BESS). Real-world operations, however, tell a different story.
In today’s high-cycle markets like CAISO, NEM, ERCOT, and Chile, battery systems routinely face more than 365 full cycles per year with standard two- or four-hour discharge profiles. Under these demanding duty cycles, extending asset life can deliver transformative financial impact.
The math is compelling: adding just five extra years of operational life can unlock an additional US $20–30/kWh in net present value (NPV) and lift internal rate of return (IRR) by approximately one percentage point for a 100 MW/400 MWh project. This shift has made asset life, not just capital expenditure, a decisive lever for long-term project value.
Recognizing this, we at Fluence have engineered our systems with hardware and software features purposefully designed to reduce maintenance needs, optimize performance, and extend asset life. But real innovation requires more than design ambition—it requires validation. To confirm our approach, we partnered with DNV to determine whether our Gridstack Pro™ platform can safely and reliably operate for 25 to 35 years. This blog post reveals the findings.
A Design-First Philosophy
From the very beginning, we built Gridstack Pro around three life-extension pillars that redefine how we approach asset longevity:
- Modular, serviceable hardware — Instead of replacing entire enclosures, owners can swap individual subsystems, reducing maintenance complexity and cost.
- Augmentation headroom — Allocated pad space and interconnection margin enable low-cost capacity “top-ups” as cell prices decline.
- Fleet-level intelligence — Advanced analytics like State of Balance (SOB), which detects and monitors State of Charge (SOC) imbalances in real time, and the Fluence Life Model, which predicts cell degradation using both lab and field data, continuously refine maintenance strategies and extend asset life.
DNV’s detailed review of our engineering and design capabilities, conducted to evaluate potential impacts on asset life, delivered a clear verdict: Gridstack Pro’s modular design and software analytics offer a reasonable pathway to 25, 30, or even 35 years of useful life.
Building on this foundation, our newest solution, Smartstack™, carries forward the same modular design principles and software intelligence, further enhanced through years of operational insights. Both Fluence and DNV anticipate equal or even greater life-extension benefits from Smartstack once its comprehensive testing campaign is complete.
Software That Stretches Every Cycle
For over a decade, our team has refined and improved our battery storage operating system, Fluence OS—a fully integrated controls system that enables system control, dispatch management, 24/7 monitoring, and massive data collection. We have extended our software suite to include cloud-based applications for intelligent bidding (Fluence Mosaic™) and asset-performance management (Fluence Nispera™), which maximize asset revenue and improve operations. Together, these applications work seamlessly across the system, from trading to operations to service, optimizing performance at every level.
As DNV noted in their assessment, “DNV looks favorably on Fluence’s approach to improving system operations to reduce stranded energy, increase system life, and support condition-based maintenance.”
Building on these foundational capabilities, we have recently expanded our software suite with additional AI-driven tools designed specifically to unlock extended life, recover lost capacity, and reduce degradation-related downtime. The table below highlights key offerings, each developed to directly support the operational and financial benefits of an over 25 year battery life.
| TOOL | CORE FUNCTIONALITY | 25 YEAR IMPACT |
| Fluence Life Model | Cell-level degradation engine calibrated with lab and fleet data | Predicts capacity fade and enables accurate project sizing |
| State of Health (SOH) | Real-time estimation and prediction of rack/node SOH | Guides dispatch, augmentation timing, and service activities |
| State of Balance (SOB) | Real-time rack/node SOC imbalance detection | Recovers stranded energy; streamlines warranty claims |
| Advanced Rolling Recalibration | Automated passive balancing | Cuts imbalance with zero downtime |
| Capacity Test Analysis | Gigawatt-scale, automated capacity-test analytics | Speeds commissioning & troubleshooting |
| Temperature Predictive Maintenance | Machine learning-based thermal-anomaly alerts | Prevents heat-driven degradation & outages |
The impact of these tools is already visible across our fleet. For instance, SOB now runs on approximately 80% of Fluence LFP-based systems (over 10 GWh), streaming billions of cell-level data points each month. At a 60 MW ERCOT site, SOB combined with rolling recalibration restored 25% stranded capacity in just eight weeks. Across our fleet, benchmarks show at least 50% less stranded energy within three months, approximately 10% shorter hot-commissioning cycles, and a +1% IRR uplift when modeled over 25 years.
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Hardware Built for Decades
DNV’s comprehensive product-architecture review confirms Gridstack Pro’s physical design can operate 25–35 years under high-cycle duty with routine maintenance. The table below outlines key design features.
| DESIGN FEATURE | WHY IT MATTERS | DNV COMMENT |
| Modular subsystems—battery modules, chillers, DC trays | Swap parts in hours, not weeks | “The standardized interface design allows the battery enclosures to be retrofitted or augmented without reducing the availability of the system.” |
| Front-facing service layout | Faster access, shorter outages | “All major components (battery racks, switchgear, HVAC units) are accessible via a hinged door, which simplifies maintenance procedures and is viewed favorably.” |
| ISO 12944 C5 coatings | ≥ 25-year corrosion resistance | “According to ISO 12944, a typical system with C5-M protection typically provides durability up to 25 years in marine environments.” |
| Quick-connect thermal loop | Replace chillers in minutes | “The use of quick-connect fittings in the thermal management system reduces maintenance duration and adds modularity.” |
| Open controls | Future controller upgrades plug-and-play | “The adoption of edge controls ensures scalability and interoperability, both of which are crucial for modular system design.” |
In practice, robust enclosures, plug-and-play controls, and field-swap thermal subsystems keep lifetime operations and maintenance (O&M) predictable and capital expenditures manageable.
Dollars and Sense: A Case Study in NPV Improvements
To quantify the value of extended asset life, we modeled a 100 MW/400 MWh California site cycling daily, with conservative assumptions:
- One percent annual revenue uplift from software improvements (throughput and uptime).
- Five percent lower engineering, procurement, and construction (EPC) costs driven solely by faster commissioning, excluding optimized labor.
Financial Impact of Extending Life to 25 Years
The results speak for themselves: pre-tax NPV rises from approximately $36 million to $46 million, while pre-tax IRR improves from 13.38 percent to 14.00 percent. Even with ultra-conservative inputs, the 25-year configuration unlocks a material boost in both value and returns.
*A more detailed, site-specific model—covering market prices, augmentation timing, and cap-and-tax structures—is available via your Fluence sales representative.
Performance Wrapped in Bankability
Our optional 25-Year Service Agreement transforms technical capability into contractual certainty, featuring capacity guarantees through Year 25, 24/7 remote monitoring and diagnostics, and on-demand engineering support for hardware, software, and compliance. All pricing, escalation terms, and remedies are custom-tailored to your project—never one-size-fits-all.
Your Path to Extended Asset Life
The energy storage industry is evolving beyond the constraints of traditional 20-year thinking. With proven technology, validated performance, and comprehensive service support, we can help you unlock the value of extended asset life.
Connect with our team to explore the full potential of your project. We can help you:
- See the Evidence: Review the full DNV Technical Note or executive summary to understand the methodology, assumptions, and findings behind our technology.
- Model Your Project: Receive a project-specific financial analysis and supporting material aligned to your duty cycle, market, and revenue stack.
- Lock in 25-Year Coverage: Learn about our 25-Year Service Agreement, including performance guarantees, monitoring options, and pricing tiers for your site.
Ready to embark on your 25-year journey with Gridstack Pro or the next-generation Smartstack™ today?
