Category: Renewable energy insurance · Reviewed by Matt Bartlett, Director · Founder · Last reviewed 2026-06-10
Lithium-ion BESS insurance is the specialist sub-class of battery storage insurance addressing the technology-specific fire, thermal runaway and serial defect exposures of grid-scale lithium-ion battery energy storage systems.
Category: Renewable energy insurance Also known as: Li-ion battery storage insurance, Lithium-ion grid storage insurance, Lithium-ion energy storage system insurance Typical UK market form: CAR/EAR + Marine Cargo + DSU + OAR + BI + Public Liability + EIL Related concepts: Battery storage insurance, Solar farm insurance, Environmental impairment liability insurance
Lithium-ion BESS insurance is the dedicated underwriting and broking practice that has emerged to address the specific risk profile of grid-scale battery energy storage systems using lithium-ion chemistries. The two dominant cathode chemistries deployed in the UK are nickel manganese cobalt (NMC), which has historically dominated the early UK fleet but is now being displaced for stationary storage applications, and lithium iron phosphate (LFP), which has become the default chemistry for new grid-scale projects from 2022 onwards due to its lower thermal runaway propensity, better cycle life and lower cobalt and nickel exposure.
The asset envelope is identical to a generic BESS — containers or buildings housing modules, PCS, transformers and switchgear — but the insurance product treats lithium-ion chemistry as a distinct rating factor. Insurers price the LFP / NMC differential explicitly and may decline NMC sites, particularly retrofitted older designs.
Construction is placed on a CAR/EAR policy, with Marine Cargo cover following battery containers from manufacturers principally in China and South Korea. Insurers’ technical surveyors typically require pre-energisation hot-spot scans and BMS commissioning evidence before risk attaches. DSU cover is sized to the contracted commercial operation date and the revenue stack.
Operational programmes combine an OAR section covering property damage and machinery breakdown with business interruption on a gross profit or revenue basis. Critically, lithium-ion BESS policies almost always carry an explicit thermal runaway deductible or sub-limit, a fire separation warranty (typically requiring six metres between containers and equivalent separation to ancillary equipment), and an explicit cycling warranty restricting deep discharge cycles or aggressive operating profiles. Environmental Impairment Liability cover is essential to address firewater run-off following a thermal runaway, which can carry heavy metal contamination requiring remediation under the Environmental Permitting Regulations.
Thermal runaway is the dominant peril and the focus of all technical underwriting attention. A thermal runaway event begins at a single cell — typically triggered by internal short circuit, overcharge, mechanical damage or external heat source — and propagates through a module via heat transfer and venting of flammable electrolyte vapour. Without effective deflagration venting and module-level fire detection, propagation through a containerised system can occur within minutes and is extremely difficult to extinguish; UK fire and rescue service tactics under NFCC guidance focus on cooling and isolation rather than extinguishment, with controlled burn-out being the standard outcome.
Public-record UK total losses include the Liverpool Carnegie Road BESS fire in September 2020, where a fire originated in one container during a routine maintenance event and burned for over a day. Internationally, the Moss Landing BESS facility in California experienced multiple thermal events, including a major fire in January 2025 that destroyed a significant portion of the site. Korean ESS losses from 2018 onwards prompted the first formal serial defect reviews of the industry. Other exposures include PCS arc-flash, BMS failure, lightning, external fire spread and cyber attack.
Battery storage was removed from the NSIP regime by the Infrastructure Planning (Electricity Storage Facilities) Order 2020 (SI 2020/1218), meaning all lithium-ion BESS regardless of capacity is consented through the local planning authority. The Health and Safety Executive published “Grid-scale battery energy storage system planning” in 2023 (with revisions in 2024) providing guidance to planners on appropriate consultation with fire and rescue services. The National Fire Chiefs Council guidance “Battery Energy Storage Systems Guidance for Fire and Rescue Services”, first issued in 2023 and updated during 2024, sets the operational fire service approach.
Manufacturing and product safety is governed by international standards including UL 9540A (test method for evaluating thermal runaway fire propagation in BESS), UL 9540 (energy storage system safety standard), IEC 62619 (industrial lithium battery safety) and BS EN 50549 (grid connection requirements). Insurers typically require UL 9540A unit-level testing as a condition of cover. Operators participating in capacity market and balancing mechanism revenue streams must hold appropriate Ofgem registrations.
Capacity for lithium-ion BESS is concentrated in a small panel of specialist underwriters in London and continental Europe. GCube (Tokio Marine HCC), Munich Re, Swiss Re Corporate Solutions, HDI Global, Allianz Global Corporate & Specialty, Liberty Specialty Markets, Markel and Tokio Marine Kiln are recurring leaders. Capacity availability has tightened progressively from 2019 onwards as loss experience accumulated, with insurers introducing serial defect sub-limits, per-container deductibles and minimum separation distance warranties as standard.
The largest broker placements are led by Marsh, Aon, WTW, McGill & Partners, Lockton and Howden, often with a specialist battery technology engineering review supporting placement. Smaller projects are placed through regional brokers, often supported by specialist MGAs.
A 50 MW / 100 MWh LFP BESS facility in the West Midlands, deploying twenty 5 MW containerised units from a Tier 1 OEM with full UL 9540A unit-level testing, would typically be insured under an OAR/BI programme with a property damage sum insured of £25–£35 million, per-container deductible of £250,000, a strict six metre fire separation warranty, a serial defect sub-limit of one container, EIL cover for firewater run-off, and a public liability tower of £25 million. Revenue stack derived from a 15-year capacity market contract, dynamic regulation services and balancing mechanism participation drives the business interruption indemnity period of 12 to 18 months.
This entry is part of the Apex Insurance Wiki. Last reviewed by Matt Bartlett on 2026-06-10. Next review: 2026-12-10.
Apex Insurance Brokers Limited. Authorised and regulated by the Financial Conduct Authority, FRN 724952. Registered in England and Wales, Companies House 07014570. This entry provides general information about UK insurance concepts and is not regulated advice. Consult your insurance broker on your specific position.
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