Clean Power Hydrogen (AIM:CPH2), the AIM-listed developer of membrane-free electrolyser technology, said its internal investigation into the 28 May incident at its test site has found no single definitive ignition source, but has identified several unrelated contributing factors.
The incident occurred during the third and final stage of factory acceptance testing of the company's 1MW MFE220 unit, which was irreparably damaged and forced CPH2 to abandon plans to resume testing on that unit.
The company said the likely contributors include gas velocity and particle impingement near valve V705 during a controlled venting process, the specification of certain check valves, hoses and pipework bends, and particle contamination linked to supplier quality and the exposed outdoor test facility.
CPH2 said it is also assessing how applicable European Industrial Gases Association guidance is to its novel technology and design basis, as part of the remedial design process.
Crucially, the company reiterated that it has found no evidence the incident originated within its proprietary membrane-free stacks or separator vessels, with certain technical aspects still subject to external verification by specialist experts.
"The investigation has now progressed sufficiently to identify the most likely causes of the incident and the principal areas requiring remedial work," said Richard Scott, chief executive, adding that the company has begun redesign and testing work while independent verification continues.
Separately, CPH2 confirmed that it will not proceed with the £750,500 secured convertible loan note agreed with Hidrigin in June, under a binding term sheet tied to a proposed strategic partnership and manufacturing agreement.
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The company has instead repaid the £750,500 interim payment it had received under the legacy MFE220 sales contract, following completion of its oversubscribed fundraising, so no loan note has been issued and no security granted.
Hidrigin's technology licence is being extended to include own-use rights in the United States, with discussions continuing on the previously announced territories of the US, Canada, Mexico and the UK, though CPH2 cautioned there is no certainty these talks will produce a definitive agreement.
The company said a revised design package will be offered to licensees and prospective manufacturing partners once testing results are satisfactory and the board approves the investigation's final conclusions.