Category: Renewable energy insurance · Reviewed by Matt Bartlett, Director · Founder · Last reviewed 2026-06-10
Battery storage insurance is the property, business interruption and liability programme placed for grid-scale Battery Energy Storage Systems (BESS), addressing fire, thermal runaway, electrical fault and revenue exposures during construction and operation.
Category: Renewable energy insurance Also known as: BESS insurance, Grid-scale battery insurance, Energy storage insurance Typical UK market form: CAR/EAR + Marine Cargo + DSU + OAR + BI + Public Liability + EIL Related concepts: Lithium-ion BESS insurance, Solar farm insurance, Business interruption insurance
Battery storage insurance is the dedicated programme covering grid-connected energy storage assets used for ancillary services (frequency response, reserve), wholesale market arbitrage and capacity market participation. The asset typically comprises battery modules housed in containerised enclosures or purpose-built buildings, power conversion systems (PCS), transformers, switchgear, the battery management system (BMS), and a fire detection and suppression system.
While “battery storage insurance” is a generic term that can apply to any chemistry, the UK operational fleet is overwhelmingly lithium-ion (NMC and LFP). The class has matured rapidly since 2018 as installed capacity has grown from a few hundred MW to several GW under construction and operation in 2024–2026, with technology and loss experience driving significant evolution of underwriting terms.
Construction is placed on a CAR/EAR policy, with Marine Cargo cover following battery containers from manufacturers in China, South Korea and increasingly the United States. DSU cover is sized to the contracted commercial operation date and the relevant revenue stack (capacity market T-1 / T-4, balancing mechanism participation, Dynamic Containment / Dynamic Regulation / Dynamic Moderation contracts with the Electricity System Operator). Insurers typically require evidence of containerised hot-spot testing and BMS commissioning before risk attaches.
Operational placements combine an Operational All Risks (OAR) policy covering property damage and machinery breakdown to battery modules, PCS, transformers and ancillary equipment with a business interruption section. Capacity for stand-alone storage is more constrained than for co-located solar + storage. Public Liability is normally placed as a stand-alone tower with explicit reference to fire spread to third-party property, and Environmental Impairment Liability cover addresses run-off of contaminated firewater following a thermal runaway event. Performance and degradation warranty cover is generally not transferable to the insurance market and is left to OEM warranty provisions.
Thermal runaway — a self-propagating exothermic reaction within a lithium-ion cell that can cascade across modules — is the central severity peril and the focus of all underwriting attention. Public-record total losses of grid-scale BESS sites in the UK and overseas (including the Liverpool Carnegie Road fire in September 2020, the Moss Landing facility in California in September 2021 and again in January 2025, and multiple Korean ESS fires from 2018 onwards) have shaped underwriting practice. Insurers require evidence of UL 9540A unit-level testing, gas detection, deflagration venting and emergency response plans aligned with the NFCC Battery Energy Storage Systems Guidance for Fire and Rescue Services (2023, updated 2024).
Other exposures include PCS inverter failure, transformer fault, switchgear arc-flash, BMS communication failure leading to mismanagement of state of charge, lightning damage and external fire. Cyber attacks on BMS and SCADA systems are a recognised but typically excluded peril, addressed through stand-alone cyber cover. Serial defect exposure across an early production module run is a recurring underwriting concern.
BESS projects were brought into the standard planning regime by the Infrastructure Planning (Electricity Storage Facilities) Order 2020, which removed lithium-ion battery storage from the NSIP regime and returned consent to local planning authorities regardless of project size. Operational guidance is set by the Health and Safety Executive’s “Grid-scale battery energy storage system planning” (2023) guidance and by NFCC fire service guidance. The Environment Agency holds responsibility for environmental permitting where applicable.
Revenue is earned through a stack of services including capacity market awards (auctioned by National Grid ESO / NESO for delivery years), balancing mechanism participation, ancillary services contracts, and merchant arbitrage in the wholesale market. The Long Duration Electricity Storage cap-and-floor regime introduced by Ofgem in 2024 provides a revenue floor for storage durations of six hours or more, supporting projects beyond the four-hour lithium-ion fleet.
Capacity for stand-alone grid-scale BESS in the UK is more constrained than for almost any other renewable energy asset class. Lloyd’s leaders are typically a small panel of energy and engineering syndicates, with GCube (Tokio Marine HCC), Munich Re, Swiss Re Corporate Solutions, Liberty Specialty Markets, HDI Global and Tokio Marine Kiln among the active markets. Many insurers have set strict eligibility criteria — preferring projects deploying UL 9540A-tested containers, with full deflagration venting and minimum separation distances between containers.
Broker placement is dominated by Marsh, Aon, WTW, McGill & Partners, Lockton and Howden, with a small number of specialist MGAs targeting the smaller co-located projects. Total insured value sub-limits, fire separation deductibles and per-container deductibles are now standard underwriting tools.
A 100 MW / 200 MWh stand-alone BESS in the East Midlands using containerised lithium iron phosphate (LFP) modules from a Tier 1 OEM, with revenue from a 15-year capacity market contract, dynamic regulation services and merchant balancing mechanism participation, would typically be insured during construction under a £40–£60 million CAR programme. On commissioning the operator places an OAR/BI policy with per-container deductibles of £250,000 to £500,000, a strict fire separation warranty, EIL cover for firewater run-off, and a public liability tower of £25–£50 million.
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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