US national lab deploys Viridi battery for grid control research

Oak Ridge National Laboratory has deployed a 146.7 kWh battery energy storage system from US manufacturer Viridi at its Grid Research Integration and Development Center (GRID-C) in Tennessee, where researchers are testing advanced grid control technologies using physical battery assets instead of simulated resources.

The project shifts testing from indoor laboratory simulations using emulated energy resources to field validation on a live grid interface. Researchers are using Viridi’s RPS 150 system at GRID-C’s outdoor Power Distribution Field Test Site to evaluate how advanced control strategies perform alongside physical equipment, complex grid interactions, and dynamic battery charging conditions encountered by electric utilities.

As distributed energy resources (DERs) expand and power grids face growing demand, coordinating battery storage across multiple grid components has become essential for system stability. ORNL’s research focuses on controlling clusters of grid assets to meet utility demand, utilizing integrated power converter systems linked directly to physical storage hardware.

The project utilized Viridi’s RPS 150 system, a point-of-use energy storage system engineered with a nominal battery capacity of 146.7 kWh (132 kWh usable) and rated for 30 kW of continuous charge and discharge power. Designed for flexible grid integration, the unit supports switchable three-phase AC connections across 208 V (83.4 A), 400 V (43.3 A), and 480 V (36.1 A) configurations via dual AC Cam-Locks, operating within an ambient temperature range of -10 C to 45 C.

The unit’s integrated battery management system (BMS) manages pack utilization in real time to regulate internal thermal conditions, communicating operating state data directly to external inverters and system controllers via CAN bus protocol.

For safety compliance, the platform holds a full UL 9540 system listing, backed by UL 9540A thermal runaway evaluation across the cell, module, and pack levels, as well as UL 1973 certification. To support larger capacity requirements, up to 16 units can be connected in parallel to provide a combined total of 480 kW of power output and 2.4 MWh of energy storage.

“This project bridges an important gap by integrating real electrical equipment to understand realistic performance challenges, proving the robustness of ORNL’s new control strategies and AC/DC architecture for supporting the future grid,” said Dr. Madhu Sudhan Chinthavali, electrical systems integration program manager at ORNL. “Viridi’s battery integrated seamlessly with our management system, and its engineering team supported our researchers throughout testing and integration.”

Buffalo-based Viridi said the selection serves as a technical validation of its fail-safe lithium-ion battery architecture. The company’s BESS design incorporates proprietary anti-propagation technology engineered to prevent thermal runaway at the cell level. This safety architecture enables deployment in high-density infrastructure applications and occupied buildings where conventional lithium-ion platforms face stringent safety and permitting hurdles.

Testing at the GRID-C facility has officially concluded, with ORNL expected to publish full findings from the project in the coming months. The deployment represents the initial phase of an ongoing research collaboration between Viridi and the national laboratory focused on grid resilience, microgrid formation, and grid modernization solutions.

From pv magazine USA