Power, capacity, efficiency, battery lifespan and cost are among the first parameters typically compared when selecting a commercial and industrial energy storage system. However, there is another critical factor to consider when evaluating a BESS — system safety.
An industrial ESS is much more than a set of batteries. It is an integrated system comprising battery cells and modules, a battery management system (BMS), power electronics, thermal management, electrical protection and control systems. This is why battery cell chemistry alone is not enough to assess ESS safety. It is equally important to understand how the entire system behaves in the event of a failure and whether it can limit the escalation of an incident.
This is particularly important to us. Suchasna Energiia is an official Huawei distributor in Ukraine, and safety is one of the key criteria we consider when evaluating the equipment we bring to the Ukrainian market. This is especially relevant for commercial and industrial energy storage systems designed for long-term operation at business and industrial facilities.
This is why the TÜV Rheinland Safety Prime certification awarded to the Huawei Smart String & Grid Forming ESS Platform deserves particular attention.
In December 2024, Huawei Digital Power became the first company to receive TÜV Rheinland’s highest Prime level certification under its ESS safety classification. The certification covered the Huawei LUNA2000-4472 and LUNA2000-215 series.
So, what exactly does Safety Prime mean, what does this certification evaluate, and why does independent safety verification matter when selecting a C&I energy storage system? Let’s take a closer look.
What Is TÜV Rheinland Safety Prime
Safety Prime is the highest, third level in TÜV Rheinland’s three-level safety classification for energy storage systems.
TÜV Rheinland conducts independent testing and certification of energy systems and their components, including batteries, control systems, inverters and interfaces. For ESS, the organization uses testing based on international standards as well as its own assessment procedures.
The Safety classification used to evaluate the Huawei platform comprises three levels:
- Level 1 — Basic. The ESS meets the basic regulatory requirements and standards required for market access.
- Level 2 — Plus. This level requires enhanced mechanical, electrical, thermal and environmental protection, including measures to prevent fires caused by thermal runaway at the battery pack level.
- Level 3 — Prime. The highest level of the classification. The system must prevent thermal runaway propagation at the battery pack level even under extreme scenarios where a fire is caused by external factors, while taking personnel safety into account.
The Huawei Smart String & Grid Forming ESS Platform achieved Level 3 — Prime. TÜV Rheinland awarded Huawei Digital Power the world’s first Prime certificate under this ESS safety classification.
Why Is Thermal Runaway So Important for ESS Safety?
One of the key risks assessed during the testing of lithium-based energy storage systems is thermal runaway.
UL Solutions defines thermal runaway as a process in which a battery cell failure leads to a rapid increase in temperature and pressure. This process can create fire and explosion hazards. Testing also evaluates whether thermal runaway can propagate from one cell to adjacent cells.
For a large-scale energy storage system, the critical question is not only whether the likelihood of a failure can be reduced, but also what happens if a failure does occur.
Will the problem remain localized?
Will thermal runaway propagate to adjacent cells or battery packs?
Can a fire spread to an adjacent ESS?
The system’s ability to contain the escalation of such an incident is therefore one of the key aspects of advanced BESS safety testing.
What Did Safety Prime Confirm for Huawei?
For Huawei, the TÜV Rheinland certification applies to the Smart String & Grid Forming ESS Platform, including the LUNA2000-4472 and LUNA2000-215 series.
According to Huawei’s information on the TÜV Rheinland testing, the platform demonstrated its ability to limit thermal runaway propagation at the battery pack level and met the requirements of the highest Prime level.
From Certification to Extreme Testing
Importantly, Huawei’s ESS safety evaluation did not end with the Safety Prime certification.
In 2025, the Huawei Commercial and Industrial Hybrid Cooling Grid Forming ESS underwent a separate extreme ignition test observed by TÜV Rheinland. Huawei reported that the test was conducted at a specialized fire safety laboratory in accordance with UL 9540A:2025.
UL 9540A is a standardized test method for evaluating fire propagation associated with thermal runaway in battery energy storage systems. UL Solutions states that the methodology evaluates system behavior at the cell, module and unit levels and is used to assess the risks associated with thermal runaway and its propagation.
During the Huawei test, deliberately severe conditions were created:
- thermal runaway was simultaneously initiated in 60 battery cells;
- all battery packs were charged to 100% SOC;
- the test scenario specified by UL 9540A:2025 was conducted with the doors open to maximize oxygen exposure;
- both active and passive fire suppression systems were disabled during the test.
The purpose was to evaluate how effectively the system’s inherent design could withstand and contain fire development under extreme conditions, rather than simply demonstrate the effectiveness of its fire suppression systems.
What Were the Test Results?
According to the results published by Huawei, the temperature in the fire zone reached 961°C during the test. At the same time, the maximum temperature of a battery cell in the adjacent ESS was 45.3°C, and the fire did not propagate between the systems. Huawei reported that the tested C&I GFM ESS met the requirements of UL 9540A:2025.
It is important not to overstate what this test demonstrates. It does not prove that a fire in an ESS is impossible. Instead, the value of such testing lies in deliberately creating an extreme failure scenario to assess how the system behaves once an incident occurs and whether the fire propagates beyond the affected system.
Why Is UL 9540A Important for Energy Storage Systems?
UL 9540A is particularly important for the BESS industry because it is not simply a battery performance test. Its full title is Standard for Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems.
According to UL Solutions, UL 9540A is a U.S. and Canadian national standard for evaluating fire propagation associated with thermal runaway in battery energy storage systems. The test method is also referenced by codes and standards related to the fire safety of energy storage systems.
For customers, testing to UL 9540A therefore provides significantly more information than a general manufacturer claim that a system “offers a high level of fire safety.” It provides a defined test scenario, an established methodology and measurable results.
ESS Safety Is Not a Single Feature
Another important takeaway from such testing is that the safety of an industrial ESS cannot depend on a single sensor, algorithm or fire suppression system.
Safety is built across multiple levels — from the behavior of individual battery cells and battery packs to the design of the entire system and its ability to limit the consequences of a failure.
This is why comparing only the following parameters is not enough when selecting an ESS:
power → capacity → battery lifespan → efficiency → cost.
Similar power and capacity ratings alone do not indicate how the system’s safety has been evaluated under failure or emergency scenarios.
This is where independent testing becomes an important additional criterion when evaluating energy storage equipment.
How Is SOC Related to This?
In 2026, Huawei received another TÜV Rheinland recognition, but it is important not to confuse it with Safety Prime.
On January 28, 2026, TÜV Rheinland awarded the Huawei Smart String Grid Forming ESS LUNA2000-(4472-5015) and LUNA2000-(107-241) platforms the highest level in a separate certification for SOC (State of Charge) characteristics.
SOC represents the estimated charge level of a battery and is one of the fundamental parameters used by the BMS.
As part of this assessment, TÜV Rheinland evaluated, among other aspects, SOC accuracy, long-term error control, automatic calibration, balancing performance and Grid Forming operation at different SOC thresholds. Huawei achieved Level 3 — Prime in this separate classification as well.
Huawei therefore received TÜV Rheinland’s highest Prime level in two separate assessment systems:
Safety Prime — assessment of ESS safety;
Level 3 — Prime for SOC — assessment of State of Charge characteristics.
These are separate certifications based on different criteria and should not be treated as a single certification.
For an industrial energy storage system, having a certain installed battery capacity is not enough. The system must also accurately determine how much of that energy is actually available at any given moment.
In 2026, Huawei and TÜV Rheinland also released a joint white paper, High-Precision SOC Algorithms for Energy Storage Systems Across Full Lifecycle. It covers SOC accuracy, automatic calibration, multi-level balancing and algorithm adaptation across different ESS operating conditions.
For customers, this has practical implications: SOC accuracy affects how effectively the system can utilize available battery capacity and manage its operating modes.
What Does This Mean for a Business Choosing an ESS?
We do not believe an energy storage system should be selected based on a single certification alone. A real-world project requires an assessment of power and capacity, the facility’s consumption profile, required backup duration, charging and discharging modes, battery lifespan, EMS and BMS capabilities, integration with an existing solar PV system or the grid, operating conditions and service requirements. Safety should be one of the key criteria in this evaluation.
Does Safety Prime mean that Huawei ESS is absolutely safe?
No. No certification means zero risk, nor does it replace proper system design, installation, commissioning and operation. Safety Prime is also not a ranking of ESS manufacturers and does not automatically identify the “best system on the market.” The certification confirms that the specific Huawei platform underwent the relevant TÜV Rheinland assessment and met the requirements of Level 3 — Prime within this ESS safety classification.
In our view, this level of precision is important when evaluating industrial energy storage equipment.
Modern Energy represents Huawei in the Ukrainian market as an official distributor, which is why we consider more than just datasheet specifications when evaluating the equipment we offer.
An industrial energy storage system is equipment designed to operate for years while interacting with a facility’s energy infrastructure. When building our product portfolio, we therefore evaluate not only power, capacity and cost, but also system architecture, battery management, independent test results and verified safety characteristics.
From this perspective, Huawei’s results deserve attention. The world’s first ESS Safety Prime certification from TÜV Rheinland for the Smart String & Grid Forming ESS Platform, followed by extreme testing of the C&I Grid Forming ESS in accordance with UL 9540A:2025 and a separate Prime-level certification for SOC characteristics, demonstrate Huawei’s consistent approach to evaluating different aspects of energy storage system performance.
For the end customer, this does not eliminate the need for professional system design and proper ESS selection. However, it provides another important consideration when choosing equipment: key system characteristics can be evaluated not only through manufacturer claims, but also through the results of independent testing.
