Power grid operators around the world face a once-in-an-industry challenge as the rapid growth of distributed resources and renewable generation increase intermittency and congestion and weaken system stability. Ultrastack™ unlocks the power of battery energy storage for transmission networks—delivering network utilization and system stabilization services that up until now could only be provided by traditional power resources.


The Fluence team understands the complexity of critical industries and will work with you to design the optimal energy storage solution for your needs.

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What does Ultrastack bring to your transmission infrastructure?

The most advanced battery storage technology available.

Advanced Controls

Redundant controls, mission critical security, and NOC integration

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99% availability

99%+ availability meets critical infrastructure requirements and asset reliability

Critical Applications

Patent pending controls applications support the most advanced transmission system use cases

Unrivaled Flexibility

Cost effective and fast installation compared to alternative technologies

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Battery based energy storage

Customer Case Study

A powerful asset for Lithuania’s European grid interconnection and renewables transition

Energy Cells (an EPSO-G company) is deploying a 200 MW/200 MWh portfolio of Fluence energy storage systems to support the country’s transmission system as it moves towards synchronization with the continental European grid, as well as the integration of fast-growing renewable energy sources.

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Watch the Webinar

Operational principles and the economics behind storage-as-transmission assets (SATA)

Consentec, ICF and Fluence experts come together to bring a wealth of expertise on SATA. They discuss the unique characteristics and needs of transmission system operators addressed by SATA, as well as its economic benefits and revenue opportunities.

watch the webinar

Battery energy storage is a proven resource for grid operators

Network Utilization

Changing generation resources and renewable intermittency causes transmission line congestion, which results in asset curtailment and re-dispatching.

Energy storage can be deployed quickly on the grid to increase transmission line capacity through energy shifting or n-1 contingency reserves.

System Stabilization

A growing share of inverter-fed resources and changing load profiles create new system stability issues for grid operators.

Energy storage with advanced grid forming controls supports grid stability and power system operation with complex applications, such as inertia, black start, oscillation damping control, and more.

Learn more about energy storage as a transmission asset


Download the White Paper


TransNet Ultrastack Rendering

Customer Spotlight

One of the world’s largest storage-as-transmission projects announced by Fluence and TransnetBW

The 250 MW Netzbooster (“Grid Booster”) project is being deployed to increase network utilisation across the German transmission system by using battery-based energy storage.

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Ultrastack delivers advanced controls applications

Synthetic Inertia

Storage provides rapid dynamic active power injection within an extremely short timeframe based on Rate of Change of Frequency (RoCoF) measured at the point of interconnection.

Grid Forming Inertia

Storage emulates the dynamic characteristics of synchronous generators with instantaneous injection or absorption of active and reactive power.

Power Oscillation Damping Control

Storage provides damping of low frequency oscillations inherent in interconnected power systems through modulation of active and reactive power.

Fluence is your trusted partner in the energy transition

Fluence delivers a full solution to our customers, combining advanced storage technology with technical expertise, market knowledge, and high voltage implementation experience.

Storage use case verification

Interconnection studies

Functional design reviews

System sizing & optimization

Tender development








Safety embedded across system design.

Fluence designs complete energy storage products with safety integrated into every layer of system controls and hardware.

Multiple layers of redundancy

Fluence OS is layered on top of all subcomponents to ensure system safety and functionality while patented control algorithms monitor and provide control over projects.

Comprehensive real-time monitoring

Fluence OS provides up-to-the-second visibility of unit performance, and continuously monitors, detects, isolates and alerts operators to potential anomalies.


Learn about safety at Fluence

Hardware-enabled safety measures

Subsystems protect themselves in event of a fault or failure in another subsystem, with all components having undergone rigorous qualifications and certifications.

Learn more on how energy storage helps address challenges faced by TSOs