Battery energy storage systems represent the fastest-growing capital asset class in the energy transition — and one of the least understood by insurers. GridGuard™ covers what standard property and engineering policies miss: the performance your battery was contracted to deliver. Capacity degradation, thermal runaway, and operational revenue loss — structured and backed by AA-rated reinsurance capacity.
Battery energy storage systems occupy a coverage gap in the insurance market. Standard property policies underwrite fire and physical damage — but not performance. Engineering policies cover construction risk — but not operational degradation. GridGuard™ was designed specifically to address the three risks that sit between standard policy wordings.
Lithium-ion battery cells are susceptible to thermal runaway — an exothermic chain reaction triggered by cell overcharge, internal short circuit, or manufacturing defect, which rapidly propagates across adjacent cells and modules. Once initiated, a thermal runaway event is typically uncontrollable with standard fire suppression. At the container and system level, a single cell failure can cascade to destroy the entire BESS asset within minutes. Documented incidents show total losses at utility-scale facilities with limited recovery from standard property coverage due to sub-limit exclusions, battery chemistry clauses, and self-ignition carve-outs in standard fire policy wording.
BESS capacity degrades with every charge-discharge cycle and over time through calendar ageing. Manufacturers warrant usable capacity at a defined degradation curve — typically guaranteeing 70–80% remaining capacity at end of warranty period (8–12 years). In practice, real-world cycle conditions, operating temperatures, depth of discharge, and charge rates can accelerate degradation beyond warranted curves. When capacity falls below contracted dispatch obligations — under grid services contracts, capacity market agreements, or PPA storage commitments — the asset faces revenue shortfall and potential contract breach. Manufacturer warranty enforcement against major Asian BESS OEMs is expensive, slow, and uncertain.
BESS assets generate revenue through grid frequency response, capacity market payments, arbitrage dispatch, and PPA obligations. Operational downtime — whether from BMS software failure, inverter faults, communication failures, or planned maintenance — translates directly into lost revenue from missed dispatch windows. Grid services contracts typically contain liquidated damages clauses for availability failures. Unlike solar assets, BESS can be dispatched at any hour, meaning a 24-hour outage during peak grid stress can erase a week's revenue. Standard business interruption products are not structured for the high-frequency, time-sensitive revenue profile of a BESS asset.
GridGuard™ is a modular BESS insurance product covering three distinct risk layers — thermal and physical, capacity performance, and operational revenue — each with its own trigger mechanism and claim settlement pathway. All three layers are placed with AA-rated reinsurance backing and can be purchased individually or as a combined policy.
GridGuard™ underwriting begins with a full BESS health assessment — State of Health (SoH) testing, BMS data extraction, cycle history analysis, and electrochemical characterisation of cell degradation. This establishes the insured capacity baseline and actual degradation rate at inception. For new systems, the OEM datasheet and commissioning test data form the baseline; for operating assets, 12 months of operational dispatch data are required. This baseline drives capacity warranty trigger thresholds and deductible structure.
The thermal runaway layer covers total or partial loss arising from a thermal runaway event, including: direct physical damage to BESS containers and associated equipment; clean-up and remediation costs (thermal events generate toxic fluoride compounds); business interruption from the date of loss; and OEM warranty backstop where the insured battery system fails outside the manufacturer's stated performance envelope prior to the event. Coverage requires FireDome, Kidde, or equivalent gas suppression systems to be installed and maintained — their presence reduces the premium significantly.
The capacity layer triggers when measured usable capacity — assessed annually using standardised IEC 62619 discharge testing — falls below the agreed warranty curve floor. The indemnity equals: (warranted capacity − actual capacity) × contracted revenue per MWh of dispatched capacity × the remaining dispatch window of the measurement period. This structure ensures the insured receives the revenue they were contracted to earn on the full warranted capacity, not a nominal replacement value for the lost cells.
The operational layer triggers when grid services revenue falls below a defined availability floor due to non-thermal operational incidents — BMS failure, inverter downtime, communication loss, or grid connection outage not caused by the grid operator. Indemnity is calculated against the BESS asset's historical revenue run rate for the equivalent period. A deductible measured in hours of downtime excludes planned maintenance windows. This layer functions as a structured business interruption product calibrated to the specific revenue profile of a dispatchable storage asset.
GridGuard™ is a three-layer BESS insurance product addressing the distinct risk profile of battery energy storage systems — from catastrophic fire events through to the quiet erosion of capacity and revenue over time.
Full replacement cost cover for BESS containers, modules, cells, BMS, inverters, and associated electrical infrastructure destroyed or damaged in a thermal runaway or fire event. Includes debris removal, fluoride compound remediation, and site reinstatement to operating condition.
Layer 1 · CoreRevenue loss from date of thermal runaway incident through reinstatement of full operational capacity, subject to a maximum indemnity period. Covers grid services revenue, capacity payments, and PPA obligations during the restoration period.
Layer 1 · IncludedInsures the revenue gap when actual usable battery capacity (measured by IEC 62619 discharge test) falls below the OEM-warranted degradation curve. Pays on a revenue basis — contracted MWh dispatch capability × energy price — not cell replacement cost. Covers degradation from cycle ageing, calendar ageing, and abnormal operating conditions.
Layer 2 · CoreWhere the BESS system experiences capacity degradation within the OEM warranty period but warranty enforcement is delayed, disputed, or the OEM is insolvent, GridGuard™ provides first-loss backstop cover — paying the revenue shortfall and pursuing recovery rights from the manufacturer on behalf of the insured.
Layer 2 · OptionalRevenue loss from non-thermal operational incidents causing availability below the contracted floor — BMS failure, inverter downtime, communication outage, or AC/DC conversion faults. Measured against the asset's historical dispatch revenue run rate. Deductible expressed in operational hours to exclude planned maintenance.
Layer 3 · OptionalWhere the insured BESS asset holds a Capacity Market agreement (UK CM, EU equivalent) or grid frequency services contract, GridGuard™ covers liquidated damages payable to the grid operator or offtaker for availability failures arising from insured events — protecting the asset owner from contractual penalty exposure.
Layer 3 · OptionalGridGuard™ serves every participant in the BESS value chain who bears performance, capacity, or operational revenue risk — from project developers and OEMs to lenders and grid services operators.
Battery storage developers use GridGuard™ to create bankable performance certainty — converting uncertain OEM warranty enforcement into a structured, insured capacity floor backed by AA-rated reinsurers. Eliminates the largest uninsured risk in a BESS project finance structure.
Banks and infrastructure lenders financing BESS assets face a collateral risk unique to battery technology: as capacity degrades, asset value falls independently of market conditions. GridGuard™ capacity warranty cover provides lenders with an insured revenue floor that protects loan-to-value ratios and DSCR covenants through the full term of a battery storage financing.
Operators of BESS assets under Capacity Market agreements, frequency response contracts, or ancillary service obligations use GridGuard™ operational BI cover to protect against liquidated damages exposure and revenue loss from unplanned downtime — turning unpredictable operational risk into a managed, insured liability.
The following cases are drawn from publicly reported incidents and official investigations. They illustrate the types of risk that GridGuard™ is designed to address. These are market examples, not Renewables Re client cases.
On 19 April 2019, a thermal runaway event initiated in a battery module at the Arizona Public Service McMicken energy storage facility — a 2 MW / 2 MWh lithium-ion BESS located in Surprise, Arizona. The thermal event propagated across the battery containers, releasing toxic fluoride gas and eventually triggering a violent deflagration explosion when firefighters opened the battery enclosure. Four firefighters were seriously injured. The facility suffered a total loss, with the physical damage to the BESS asset estimated at $5–7 million. The NTSB investigation, published in 2020, identified internal cell failure as the initiating event and criticised the absence of adequate gas detection, suppression, and emergency response protocols for BESS thermal events. The incident exposed a fundamental gap: standard property insurance excluded the self-ignition cause of loss, and the battery OEM warranty did not cover consequential property damage or business interruption arising from a thermal runaway.
The McMicken incident became a watershed event for BESS insurance globally. Prior to it, most utility-scale BESS assets were insured under standard commercial property forms with minimal BESS-specific endorsements. Post-McMicken, insurers globally began adding battery technology exclusions, self-ignition carve-outs, and sub-limits to standard property policies — often leaving BESS operators with coverage gaps of 40–70% of replacement value. Specialist BESS insurers and Lloyd's market syndicates responded by developing dedicated BESS product forms covering thermal runaway as a named cause of loss, with coverage conditioned on installation of approved gas detection systems, thermal management controls, and emergency response protocols. The NTSB report became the de facto underwriting checklist for specialist BESS insurers worldwide. GridGuard™ was developed in direct response to this coverage gap, incorporating NTSB-recommended safety standards as underwriting conditions that reduce — rather than exclude — the insured risk.
The McMicken incident established that thermal runaway in BESS is not a theoretical tail risk — it is an operating reality that has caused documented loss at major utilities. The insurance industry response — adding exclusions rather than developing coverage — created a market gap that persists today. The majority of BESS assets currently operating in Europe and the UK are insured on property forms with self-ignition exclusions or sub-limits that would not respond adequately to a McMicken-scale event. GridGuard™ addresses this directly: thermal runaway is a named insured peril, covered at full replacement cost, with cover conditioned on NTSB-recommended suppression and monitoring standards — creating an insured that is both protected and demonstrably better managed.
Between August 2017 and June 2019, South Korea experienced 28 confirmed BESS fire incidents at facilities across the country — a frequency that alarmed the government, insurers, and the global energy storage industry. The fires occurred across a range of manufacturers and installation types, from small commercial rooftop systems to multi-MWh utility-scale facilities. The cumulative physical damage was estimated at KRW 25–35 billion (approximately USD 21–29 million). A government investigation led by the Ministry of Trade, Industry and Energy (MOTIE) identified four primary causes: battery cell manufacturing defects, failures in battery protection systems, installation errors including improper grounding, and inadequate operational management. Samsung SDI and LG Energy Solution modules were among the most affected, and both manufacturers faced significant warranty claims that were disputed due to ambiguity over whether the fires arose from cell defects or installation practices.
The South Korean BESS fire wave created an acute insurance market dislocation. Korean general insurers, who had been covering BESS assets under standard fire and engineering policies with minimal BESS-specific underwriting, faced aggregate losses across multiple policies simultaneously. Many claims were disputed on grounds that the fires constituted self-ignition or design defect — exclusions in standard Korean property forms. The government's MOTIE investigation recommended mandatory installation of fire detection systems, arc fault detection, and grounding systems as prerequisites for grid connection of BESS facilities. Korean insurers responded by either exiting the BESS segment or radically increasing premiums and sub-limits. The international reinsurance market tightened BESS exposure globally as a result. The incidents also triggered the first structured BESS manufacturer warranty insurance products in Korea — covering the gap between OEM warranty and property insurance in cases where the cause of fire was disputed.
The South Korean experience demonstrates that BESS fire risk is systemic, not individual — when a battery chemistry or installation practice is deficient, losses occur simultaneously across multiple sites and policies. For European BESS operators, the lesson is clear: as CEE and EU markets scale up BESS deployment under the EU Battery Regulation (2023/1542) and the revised EBRD and EIB green finance frameworks, the same concentration of risk that broke the Korean insurance market is building in Europe. GridGuard™ addresses the Korean gap directly: thermal runaway is a named insured peril; OEM warranty backstop is available where disputes arise; and mandatory safety system installation conditions align the insured's behaviour with risk reduction — rather than simply loading exclusions on a standard property form.
On 16 January 2025, a major fire broke out at Vistra Energy's Elkhorn Battery Storage facility at Moss Landing, Monterey County, California — the largest operational BESS facility in the world at the time, rated at 300 MW / 1,200 MWh. The fire burned for several days, requiring the evacuation of approximately 1,200 residents due to toxic smoke from burning lithium-ion cells. CalFire ultimately declared the facility a total loss. Preliminary loss estimates from industry analysis placed the insured property loss at $250–500 million, making it the single largest BESS insurance loss event in history. The facility had previously experienced a smaller fire in September 2022, which had been contained but which prompted CalFire to develop the first state-level BESS emergency response guidelines. The 2025 fire occurred in a portion of the facility that had been expanded and recommissioned after the 2022 event. Beyond physical damage, the loss of 1,200 MWh of grid storage capacity created grid reliability concerns for CAISO during peak demand periods, with revenue loss to Vistra estimated at tens of millions of dollars during the extended outage.
The Moss Landing 2025 loss immediately triggered a global BESS insurance market response. Lloyd's of London syndicates active in the BESS space began revising capacity limits, introducing mandatory suppression system requirements, and adding co-insurance requirements for facilities above 100 MWh. Several specialist insurers suspended new BESS business while loss data was assessed. The event highlighted the inadequacy of standard property policy forms for large-format BESS — specifically the gap between fire suppression capability and the reality of lithium-ion thermal runaway at scale. Reinsurers began revising BESS accumulation models and introducing per-event BESS sub-limits across property catastrophe reinsurance treaties. The loss also accelerated regulatory action: CPUC and CARB issued emergency guidance on BESS site spacing, setback requirements, and suppression standards. Operators with standalone BESS insurance products providing named peril thermal runaway cover experienced no coverage disputes; those relying on standard property forms faced significant exclusion arguments.
Moss Landing 2025 confirmed what McMicken 2019 and South Korea 2017–2019 had signalled: thermal runaway in large-format BESS is a loss that will periodically generate nine-figure property damage and extended business interruption. It also demonstrated that business interruption from BESS loss is not merely the direct revenue gap at the damaged facility — it can include grid system costs, capacity replacement costs, and regulatory penalties. For European BESS developers and lenders, the incident arrives at a critical moment: CEE BESS deployment is accelerating under national energy storage strategies, and the insurance market is simultaneously tightening capacity and raising premiums. GridGuard™ is positioned to provide the coverage certainty that the post-Moss Landing market requires — with thermal runaway as a named peril, structured BI, and AA-rated reinsurance backing that survives the market disruption that surrounds a major BESS loss event.
Indicative policy parameters for GridGuard™ BESS Performance & Operations Insurance. All terms are subject to underwriting and risk assessment. Contact us for a tailored quotation.
| Parameter | Detail |
|---|---|
| Eligible assets | Utility-scale BESS (≥500 kWh / 250 kW); commercial BESS (≥100 kWh) subject to underwriting review; co-located solar+storage and standalone storage accepted; AC- and DC-coupled configurations |
| Battery chemistries | Lithium iron phosphate (LFP), lithium NMC/NCA, vanadium redox flow (VRFB). Lithium-sulfur and solid-state: moratorium pending 2026 review. NaS accepted subject to risk assessment. |
| Minimum operational history | Layer 1 (Thermal): new systems accepted subject to commissioning certification. Layer 2 (Capacity): 12 months SoH baseline required. Layer 3 (BI): 6 months dispatch data required. |
| Policy term | 1 year (renewable) to 15 years (fixed, aligned to project finance or long-term grid services contract) |
| Capacity trigger mechanism | IEC 62619 standardised discharge test to rated capacity at 25°C, conducted by accredited laboratory at policy anniversary. Trigger threshold agreed at inception based on OEM warranty curve. |
| Deductible — thermal layer | First loss deductible: 5–10% of insured replacement cost (risk-based; reduced for facilities with FireDome/Kidde Class D suppression systems and 24hr monitoring) |
| Deductible — capacity layer | Annual aggregate: degradation within OEM warranted curve is excluded. Cover attaches at first MWh of capacity loss below warranted floor. |
| Deductible — BI layer | Time deductible: 24–48 hours of downtime (excludes planned maintenance windows scheduled ≥72 hours in advance) |
| Maximum sum insured | €100M per site (combined layers); portfolio aggregation available up to €300M with reinsurer approval |
| Geographic scope | Czech Republic, Slovakia, Poland, Hungary, Romania, Croatia; United Kingdom; broader EU/EEA subject to reinsurer approval |
| Reinsurance | 100% ceded to AA-rated institutional reinsurer; ČNB-licensed broker (HIB Re / Renewables Re) |
| Pre-inception requirements | State of Health (SoH) testing report; commissioning test data; BMS specification and alarm log review; suppression and monitoring system certification; O&M contract review; grid connection agreement |
| Settlement | Thermal claims: 30-day assessment period from incident report; payment within 45 days. Capacity claims: 30 days from IEC 62619 test results. BI claims: monthly rolling assessment during outage period. |
Send us your BESS specifications, SoH baseline data, and grid services contracts. We will assess the risk, commission the health evaluation, and return an indicative premium across all three coverage layers within 10 working days.