Clearstone Energy’s Axminster Energy Hub, set to be a 150 MW battery energy storage system (BESS), has had its appeal rejected by the planning inspector appointed by the Secretary of State.

Clearstone Energy (Clearstone) had announced the project in 2023, following its receipt of a grid connection at National Grid’s Axminster Substation, located 4 km to the east of Axminster, near the border of Devon and Dorset in England.

It applied for a permit to East Devon District Council (EDDC) in early 2024 under application 24/0096/MFUL, which was rejected by the Council in May 2025. At the council’s 3.5-hour-long hearing, there was significant local pushback against the potential for fires and concerns about pollution of local water sources.

Clearstone appealed, though the EDDC withdrew its opposition during the appeal process following a meeting on January 14, 2026. That left the opposition to local groups dubbed a “Rule 6 Party,” which continued to oppose the appeal. Local groups have fought against several BESS projects in the area, raising considerable funds to support fielding expert advice at hearings.

Following a hearing and lengthy decision process, planning inspector Helen Heward dismissed the appeal on August 13, 2026, in a 17-page decision.

In the statement, which accounts for all preliminary matters, two “Main Issues” were noted.

“i) The risk of a fire event and whether, in the event of a fire, the proposed fire safety and pollution control measures would be sufficient to prevent pollution of aquifers and control the quality of groundwater, with particular regard to the health and safety of local residents.

“ii) The effect of the proposal upon the character and appearance of the local area including the Dorset National Landscape.“

In the latter issue, detailed discussions of the BESS’s “alien” appearance were mentioned in the context of the natural landscape. More than a dozen points on this matter were made.

The discussion of fire risk, however, was far more substantial.

Risk of fires

Clearstone nominated the Wärtsilä Quantum 1 BESS, a lithium iron phosphate battery type, for the site. 52 units were scheduled for installation.

In the decision, the Wärtsilä Quantum 1 BESS system was noted as being installed at 100 sites worldwide and 9 sites in the UK, including the UK’s largest BESS facility at Blackhillock in Scotland. It was noted as meeting regulations, including “NFPA 855 minimum standards for BESS hazard mitigation, NFPA 69 Standard on Explosion Prevention Systems, and NFPA 68 standard on Explosion Protection by Deflagration Venting”, and the large-scale first test (LSFT) for the Quantum 1 was examined in the hearing. It was noted that the technology had a 100% safety track record.

Fire experts represented both sides of the appeal, with Martin Blunden acting as an expert for Clearstone Energy, a “Member of the Institute of Fire Engineers, a former Chief Fire Officer of the Scottish Fire and Rescue Service with extensive experience in the UK Fire and Rescue sector, including roles for the National Fire Chiefs Council on Health and Safety.”

Acting for the Rule 6 Party, Jeremy Ramsden accepted that, based on 2025 failure rates, there was a 99.76% chance of no fire in any given year. Over the site’s planned 40-year lifetime, Ramsden provided standard calculations indicating an approximate 10% probability of at least one fire.

Developers typically question this logic with caveats that batteries are monitored, and typically augmented or replaced during a project lifetime as they degrade. The decision notes that replacements would happen at around 15 years. Typically, engineers also point to bathtub curves that dictate failure rates versus a single static number, though the planning inspector notes there is not one industry-agreed model.

Also used as evidence were reports from Clean Energy Associates, which found that “26% of BESS units inspected had defects in the fire suppression system, 18% had thermal management system defects, and system-level defects accounted for nearly 50% of all quality assurance findings.”

Decision

The planning inspector noted, “I am not persuaded that there is sufficient robust evidence to demonstrate that the deflagration/explosion mitigation strategies would work effectively and that explosion hazards would be satisfactorily controlled for cabinets 10cm apart.”

Heward continued, “Whilst the issue may be finely balanced, as a matter of fire safety, this weighs very heavily against the proposal. And, as the evidence for pollution control is predicated on the fire safety evidence, it follows that I cannot be confident that pollution control measures, such as the extent and size of the fire water retention blanket, would be sufficient to prevent pollution of aquifers and control the quality of groundwater.”

ESS News contacted Clearstone for comment, and Rob Garratt, head of development, Clearstone Energy, sent the following statement.

This is a deeply concerning decision for anyone with BESS projects in the UK and for a Government that has worked hard to reassure that the right processes and guidelines are in place to ensure that the 25GW increase in BESS in its Clean Power Plan requirements can be delivered safely.

The NFCC guidance was followed to the letter with a comprehensive pre-application consultation with DSFRS and a proposal that went above and beyond the NFCC Guidance in place when the planning application was submitted (2023) and therefore met the 2026 update to the guidance.

A BESS manufacturer, Wärtsilä, was specified within the planning application. The system is proven in the field, maintains a 100% safety record, and has successfully passed all safety tests, including the Large Scale Fire Test, which is now part of UL9450A and therefore the latest NFCC guidance.

East Devon District Council decided not to defend the appeal following expert review of the proposal.

This decision effectively says to Councils that being compliant with the NFCC guidance isn’t enough to demonstrate that safety has been satisfactorily addressed. It risks undoing all the good work that has been done by manufacturers, the fire service and Government to ensure and assure that UK BESS schemes will operate safely.

Clearstone Energy maintains that this is a well-designed and much-needed project to support the UK’s Clean Power ambitions. We are reviewing the options available to us to challenge this decision for this project, but also the wider industry.

The post Blocked BESS in Britain: Clearstone’s appeal fails for 150 MW site at Axminster [UPDATED] appeared first on Energy Storage.

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