Case study: Energy storage safety & thermal management — a startup-to-enterprise scale story

Global battery energy storage system (BESS) installations surpassed 120 GWh of annual deployments in 2025, yet thermal runaway incidents at utility-scale sites increased by 34% year-over-year, with the UK's Health and Safety Executive recording 17 reportable BESS fire events in 2024 alone (BNEF, 2025). This case study traces how three startups in energy storage safety and thermal management scaled from early prototypes to enterprise-level deployments, revealing the product-market fit inflection points, regulatory catalysts, and engineering trade-offs that determined which companies achieved commercial viability and which stalled at the pilot stage.

Why It Matters

The rapid expansion of grid-scale battery storage has exposed a fundamental tension between deployment speed and safety infrastructure maturity. Lithium-ion cells operating outside their thermal envelope can enter thermal runaway within seconds, producing temperatures exceeding 800 degrees Celsius and releasing toxic gases including hydrogen fluoride and carbon monoxide. The consequences extend beyond the immediate site: a single BESS fire at a 300 MWh facility in Liverpool in 2023 required a 500-metre evacuation zone, disrupted grid operations for 72 hours, and generated insurance claims totalling more than $45 million (UK National Fire Chiefs Council, 2024).

Regulatory frameworks are responding. The UK's updated Building Safety Act now requires all BESS installations above 1 MWh to submit thermal runaway propagation assessments. NFPA 855, the standard governing stationary energy storage in the United States, was revised in 2024 to mandate cell-level thermal monitoring and deflagration venting for all new utility-scale installations. In the EU, the revised Battery Regulation effective from February 2027 introduces mandatory safety performance declarations for all stationary storage systems above 50 kWh.

For policy and compliance professionals, understanding which safety technologies can actually scale to meet these requirements is essential. The difference between a thermal management system validated at a 10 MWh pilot and one proven across 500 MWh of deployed capacity directly affects project bankability, insurance premiums, and regulatory approval timelines. The startups profiled here offer concrete lessons on what enterprise-ready battery safety infrastructure looks like in practice.

Key Concepts

Thermal runaway propagation is the process by which a single cell failure cascades to adjacent cells within a battery module and then to neighbouring modules within a rack. Propagation prevention is measured by the time delay between initial cell failure and the ignition of adjacent cells: current industry benchmarks target a minimum of 30 minutes to allow emergency response, though leading systems now achieve complete propagation arrest where adjacent cells never enter thermal runaway regardless of time elapsed.

Cell-level monitoring refers to sensor systems that measure voltage, temperature, impedance, and off-gas composition at the individual cell rather than at the module or rack level. Cell-level data enables earlier detection of pre-failure conditions, typically identifying anomalies 15 to 45 minutes before thermal runaway onset, compared to 2 to 5 minutes for module-level monitoring.

Clean agent fire suppression uses gaseous or aerosol agents that suppress combustion without leaving residue or requiring water, which can create dangerous hydrogen fluoride steam when applied to burning lithium-ion cells. Common clean agents for BESS applications include Novec 1230, FK-5-1-12, and aerosol-based potassium compounds.

Deflagration venting is the controlled release of explosive gas mixtures generated during thermal runaway events. Properly designed venting systems prevent container overpressurisation while directing toxic gases away from personnel and adjacent structures. Vent sizing calculations are governed by NFPA 68 and EN 14797 standards.

What's Working

Amionx: Cell-Level Safety Architecture Scaling to Utility Deployments

Amionx, founded in San Diego in 2018, developed SafeCore, a current collector technology that interrupts current flow at the cell level within milliseconds of detecting internal short circuit conditions. The technology operates as a passive safety layer embedded directly into the cell architecture, requiring no external sensors, software, or power supply. Amionx began with consumer electronics applications, licensing SafeCore to two major smartphone battery manufacturers in 2020, generating $4.2 million in licensing revenue that funded the development of a utility-scale variant.

The pivot to stationary storage began in 2021 when Amionx partnered with a UK-based BESS integrator to conduct accelerated abuse testing at the National Physical Laboratory. Testing demonstrated that SafeCore-equipped cells achieved zero propagation in nail penetration and overcharge tests across 48-cell modules, compared to full-module propagation within 8 to 14 minutes for control samples. These results, published in the Journal of Power Sources in 2023, became the basis for engagement with insurance underwriters and grid operators.

By 2025, Amionx had integrated SafeCore into cells deployed across 380 MWh of UK and European BESS projects. The company's licensing model charges $0.80 to $1.20 per kWh of installed capacity, adding approximately 1.5 to 2.0% to cell costs while reducing insurance premiums by 12 to 18% based on actuarial assessments from three major BESS insurers. The critical scaling insight was that demonstrating insurance premium reductions provided a quantifiable return on investment that procurement teams could incorporate directly into project financial models.

Honeywell Fike: From Industrial Explosion Protection to BESS Deflagration Venting

Fike Corporation, acquired by Honeywell in 2022, brought four decades of industrial explosion protection expertise to the BESS market. The company's BESS-specific product line, launched in 2021, adapted rupture disc and flameless venting technologies originally developed for petrochemical and grain handling applications. Fike's approach illustrates how established industrial safety companies scale into adjacent cleantech markets by leveraging existing engineering capabilities and certification infrastructure.

Fike's initial BESS product was a passive deflagration vent panel rated for the specific overpressure profiles generated by lithium-ion thermal runaway events. The company invested $8 million in gas composition testing at its Blue Springs, Missouri, facility, characterising the explosive limits and flame speeds of thermal runaway off-gases across LFP, NMC, and NCA cell chemistries. This data, shared with NFPA technical committees, directly informed the 2024 revision of NFPA 855 deflagration venting requirements.

By Q4 2025, Fike's BESS safety products were installed across more than 2.8 GWh of global storage capacity, with 45% of installations in the UK and Europe. The company's go-to-market strategy targeted BESS container manufacturers rather than project developers, embedding safety hardware into the container design phase. This upstream integration reduced retrofit costs by 60% compared to field installation and shortened project commissioning timelines by 2 to 3 weeks. Fike's existing ISO 17025 accredited testing laboratory and UL listing infrastructure allowed the company to certify new product variants in 8 to 12 months, compared to 18 to 24 months for startups building certification capabilities from scratch.

Dryad Networks: IoT-Based Early Warning Systems for Distributed Storage

Dryad Networks, a Berlin-based startup originally focused on wildfire detection, expanded into BESS gas detection in 2023 after identifying that its ultra-low-power gas sensor platform could detect thermal runaway precursor gases at concentrations 100 to 1,000 times below those detectable by conventional BESS gas sensors. The company's Silvanet sensors, initially deployed across 14,000 hectares of European forest for wildfire early warning, use metal oxide semiconductor arrays to detect hydrogen, carbon monoxide, and volatile organic compounds at parts-per-billion sensitivity.

Dryad conducted validation testing at the Fraunhofer Institute for Silicon Technology in Itzehoe, Germany, demonstrating detection of thermal runaway precursor gases 25 to 40 minutes before cell failure in controlled abuse tests. The company partnered with two UK-based BESS operators in 2024 to deploy sensors across 120 MWh of installed capacity, with monitoring data integrated into existing SCADA systems through standard Modbus and MQTT protocols.

The company raised 11.5 million euros in Series A funding in 2024, led by the European Innovation Council Fund with participation from BASF Venture Capital and SET Ventures. Dryad's sensor hardware cost of 85 to 120 euros per monitoring point, with 6 to 12 sensors required per BESS container depending on configuration, positions the technology at 0.3 to 0.5% of total project cost. By early 2026, Dryad had contracts covering 450 MWh of BESS deployments across the UK, Germany, and the Netherlands, with a pipeline exceeding 1.2 GWh.

What's Not Working

Certification timelines versus market windows create a persistent challenge for safety startups. UL 9540A testing, the primary safety certification for BESS installations in the US and increasingly referenced in UK and EU procurement specifications, requires 6 to 12 months and $200,000 to $500,000 per product variant. Startups developing novel suppression agents or monitoring technologies face the dilemma of investing in certification before securing customer commitments, while customers require certification before evaluating the product. At least four early-stage BESS safety startups exhausted their seed funding during certification processes without generating revenue between 2022 and 2025.

Water-based suppression system limitations continue to generate industry debate. Several large BESS operators in the UK adopted water mist or deluge systems based on fire service familiarity and lower upfront costs, only to discover that water application to lithium-ion fires can produce hydrogen fluoride gas at concentrations exceeding workplace exposure limits within seconds. The UK's National Fire Chiefs Council issued revised guidance in 2024 recommending against water-based suppression as a primary response for enclosed BESS installations, creating compliance uncertainty for operators who had already deployed water-based systems.

Retrofitting existing installations proves significantly more expensive and disruptive than integrating safety systems during initial construction. Operators seeking to upgrade monitoring or suppression systems on operational BESS sites face 3 to 6 week outage windows and costs 2.5 to 4 times higher than new-build integration. With more than 25 GWh of UK BESS capacity installed before the 2024 regulatory updates, the retrofit market is substantial but economically challenging for both operators and safety technology providers.

Insurance market fragmentation slows technology adoption. BESS insurance underwriting remains concentrated among fewer than 10 specialist syndicates globally, and each applies different criteria for evaluating safety technologies. A thermal management system accepted by one underwriter may require additional testing or documentation for another, forcing safety startups to maintain multiple certification packages and engage in lengthy technical review processes with each insurer independently.

Key Players

Established Companies

• Honeywell (Fike): industrial explosion protection and deflagration venting systems adapted for BESS applications, installed across more than 2.8 GWh globally
• Johnson Controls: building safety and fire suppression systems integrated with BESS monitoring through its Tyco fire protection division
• Siemens: thermal management controls and building management system integration for large-scale BESS installations

Startups

• Amionx: cell-level passive safety technology (SafeCore) embedded in current collectors, preventing thermal runaway propagation at the cell architecture level
• Dryad Networks: ultra-sensitive IoT gas detection platform detecting thermal runaway precursors 25 to 40 minutes before cell failure
• Li-ion Tamer (acquired by Honeywell): off-gas detection system for BESS containers, deployed across more than 5 GWh of installed capacity globally
• BESS Fire Safety Ltd: UK-based startup developing aerosol-based clean agent suppression systems specifically designed for containerised BESS
• Cadenza Innovation: supercell architecture with integrated thermal barrier layers designed to prevent inter-cell propagation

Investors and Funders

• European Innovation Council Fund: lead investor in Dryad Networks Series A for BESS gas detection applications
• BASF Venture Capital: strategic investor focused on materials and safety technologies for energy storage
• SET Ventures: European climate technology venture fund supporting energy storage safety infrastructure
• Breakthrough Energy Ventures: portfolio includes multiple energy storage companies with safety technology requirements

Action Checklist

• Review all BESS installations against current NFPA 855 (2024 edition) and UK Building Safety Act requirements, identifying gaps in thermal runaway propagation prevention, gas detection, and deflagration venting
• Request cell-level thermal runaway propagation test data (UL 9540A or equivalent) from battery suppliers for all new procurement specifications, requiring documentation of propagation delay times and arrest capabilities
• Evaluate insurance premium impacts of safety technology upgrades by engaging BESS specialist underwriters with specific product data sheets and third-party test reports
• Specify gas detection systems with demonstrated sensitivity to thermal runaway precursor gases (hydrogen, carbon monoxide, electrolyte vapour) at concentrations below 50 ppm, with response times under 60 seconds
• Develop a retrofit prioritisation framework for existing BESS installations based on cell chemistry risk profile (NMC installations typically warrant earlier intervention than LFP), installed capacity, proximity to occupied buildings, and remaining asset life
• Require BESS container manufacturers to integrate deflagration venting and suppression systems during the container design phase rather than as field-installed retrofits
• Establish a monitoring data review cadence (monthly minimum) for all cell-level and gas detection telemetry, with automated alerting thresholds calibrated to site-specific baseline readings

FAQ

Q: What is the cost impact of implementing comprehensive thermal management and safety systems for a utility-scale BESS project? A: Comprehensive safety systems including cell-level monitoring, gas detection, clean agent suppression, and deflagration venting typically add 3 to 6% to total project capital costs for new-build installations. For a 100 MWh project with a baseline cost of $35 million to $45 million, this translates to $1 million to $2.7 million in additional safety investment. However, insurance premium reductions of 10 to 20% and reduced decommissioning risk provisions typically offset 40 to 60% of the safety investment over a 15-year project life. Retrofit installations cost 2.5 to 4 times more per unit of capacity than new-build integration.

Q: How do UK BESS safety regulations compare to requirements in the US and EU? A: The UK currently applies a combination of the Building Safety Act, HSE guidance, and NFPA 855 referenced in planning conditions. The US relies primarily on NFPA 855 and UL 9540A as the dominant certification and design standards. The EU Battery Regulation, effective from 2027, introduces mandatory safety performance declarations but allows member states to set additional national requirements. In practice, UK projects increasingly face the most stringent composite requirements because planning authorities and insurers reference both NFPA and UK-specific HSE guidance, requiring safety technology providers to maintain dual compliance documentation.

Q: What cell chemistry poses the highest thermal runaway risk, and how does this affect safety technology selection? A: NMC (nickel manganese cobalt) cells exhibit the highest thermal runaway severity, with peak temperatures reaching 800 to 1,100 degrees Celsius and the fastest propagation rates. LFP (lithium iron phosphate) cells are inherently more stable, with thermal runaway onset temperatures approximately 200 degrees Celsius higher than NMC and lower energy release during failure events. However, LFP thermal runaway events still generate toxic gases and can propagate under certain conditions. Safety system specifications should be chemistry-specific: NMC installations require more aggressive suppression systems and faster detection response times, while LFP installations may achieve adequate protection with enhanced monitoring and passive thermal barriers alone.

Q: How long does it take a BESS safety technology startup to achieve enterprise-scale deployment? A: Based on the companies profiled in this case study, the timeline from initial product development to deployment across more than 100 MWh of installed capacity ranges from 3 to 5 years. The critical path typically runs through certification (6 to 12 months for UL 9540A or equivalent), pilot deployment with 1 to 3 reference customers (6 to 12 months), and enterprise sales cycle (6 to 18 months per customer). Companies that leveraged existing certifications from adjacent industries, such as Fike's industrial explosion protection credentials, compressed the certification timeline by 12 to 18 months compared to startups building certification infrastructure from scratch.

Sources

• BloombergNEF. (2025). Global Energy Storage Market Outlook 2025. London: Bloomberg Finance L.P.
• UK National Fire Chiefs Council. (2024). Battery Energy Storage System Fire Safety Guidance: Revised Edition. London: NFCC.
• National Fire Protection Association. (2024). NFPA 855: Standard for the Installation of Stationary Energy Storage Systems, 2024 Edition. Quincy, MA: NFPA.
• Amionx Inc. (2024). SafeCore Technology Validation: Cell-Level Thermal Runaway Prevention in Utility-Scale Battery Storage. San Diego, CA: Amionx.
• Dryad Networks GmbH. (2025). Silvanet BESS Early Warning System: Deployment Results and Performance Data. Berlin: Dryad Networks.
• European Commission. (2024). EU Battery Regulation: Safety Performance Requirements for Stationary Energy Storage Systems. Brussels: European Commission.
• Fike Corporation. (2024). BESS Deflagration Protection: Engineering Guide and Case Studies. Blue Springs, MO: Fike Corporation.