The Menai data centre proposal on a former industrial site near Caernarfon is facing mounting opposition, with more than 22,000 people reported to have signed a petition and a protest planned for 10th October 2026. The latest mobilisation comes as a statutory planning consultation approaches its 17th October deadline.
Developer Gwelyfenai Ltd is seeking outline permission for a data centre campus at and adjoining the former Ferodo and Friction Dynamics factory at Griffiths Crossing, between Caernarfon and Y Felinheli. The application covers about 41 hectares and proposes new buildings, supporting plant, generators, substations, roads and engineering infrastructure.
Cyngor Gwynedd has not granted planning permission for the development. An Environmental Statement is now part of the application, bringing questions about landscape, electricity, water, traffic and biodiversity into a formal assessment. For Welsh planning professionals, the immediate issue is the evidence needed to determine a large, energy-intensive scheme beside a sensitive coastal environment.
Menai data centre application and EIA
The formal reference is C25/0740/20/EIA. The Menai data centre application was submitted in October 2025 as an outline proposal with all matters reserved. That means the present process is considering the principle of the proposed development; it is not an approval of a final detailed layout or building design.
A Regulation 19 public notice published on 16th September 2026 confirms that an Environmental Statement was submitted under the Town and Country Planning (Environmental Impact Assessment) (Wales) Regulations 2017. It specifies demolition, site regrading, data centre buildings, generators, substations, access, parking, drainage and service works.
The notice gives 17th October 2026 as the final date for representations. Application papers and the Environmental Statement can be inspected through Gwynedd Council’s planning register. A previous screening opinion concluded that an Environmental Impact Assessment was required.
Why the Menai Strait location matters
The Menai data centre site has an industrial history, but it also occupies a highly visible position near the Menai Strait. News reporting describes proposals for several large buildings, potentially reaching about 30 metres in height. The approximately 41-hectare red-line area extends beyond the footprint of the old factory.
That distinction matters. Redeveloping previously industrial land may offer benefits, but an outline application must still establish whether the proposed scale, built form, access arrangements and likely environmental effects are acceptable in this particular setting. Existing industrial use does not, by itself, determine the outcome of a much larger proposal.
Objectors have highlighted the landscape of the Strait and views towards Eryri, together with potential implications for protected marine habitats and nearby ecological designations. The material planning questions include effects on designated sites, construction disturbance, lighting, operational noise, drainage and the adequacy of mitigation, judged against the submitted evidence.
Electricity, water and operational impacts
The proposed electricity connection has been reported at about 450MW. That figure describes requested connection capacity, not verified continuous consumption. Backup generation, cooling equipment and other plant form part of the planning proposal and are relevant to assessments of noise, air quality and emissions.
Campaigners have drawn attention to figures cited from the environmental material suggesting typical water demand of around 700,000 litres daily and a considerably higher modelled maximum. These figures require careful reading in context: a maximum scenario is not the same thing as predicted everyday use, and assumptions about cooling technology and supply must be tested against the actual application documents.
The applicant has said that cooling arrangements would recirculate water, and that concerns based on the operation of different data centres should not automatically be applied to this scheme. Those assurances are relevant, but the planning decision must rest on the evidence, any necessary mitigation and legally enforceable conditions rather than either side’s projections alone.
Jobs, regeneration and the former Ferodo site
Gwelyfenai Ltd presents the scheme as an opportunity to put a long-derelict industrial location back into economic use. Developer estimates reported in September suggest more than 900 construction jobs and around 200 ongoing roles, although those are forecasts rather than secured employment outcomes.
The former Ferodo factory was a significant local employer. Its history also includes the lengthy Friction Dynamics industrial dispute in the early 2000s. That background helps explain why regeneration and employment are prominent in the debate, even among residents who question whether the proposed scale is appropriate.
For decision-makers, it will be important to distinguish the physical environmental consequences of the project from claimed economic benefits, and to understand which benefits would be local, deliverable and capable of being secured. Neither economic opportunities nor environmental concerns can properly be resolved by headline numbers alone.
Petition and protest increase scrutiny
Reporting published on 8th October says the petition opposing the Menai data centre has passed 22,000 signatures. Campaigners have announced a demonstration in Caernarfon on Saturday 10th October, beginning at 11am. A petition signature is not automatically a formal planning representation, so the headline total must not be treated as the number of objections submitted to Gwynedd Council.
Dwyfor Meirionnydd MP Liz Saville Roberts has questioned the scheme’s scale and the strength of its projected employment benefits. Her criticism has focused on whether a development of this size is justified beside the Menai Strait. Other political representatives have also raised concerns about resources, landscape and habitats.
The developer, meanwhile, has acknowledged that questions about employment, water, wildlife and noise are reasonable. It disputes some claims made about data centres elsewhere, and says the scheme would deliver investment, employment and improvements to a neglected site. These competing positions now need to be examined through the statutory planning process rather than treated as findings of fact.
What happens next in Welsh planning
The outstanding action for interested parties is to submit evidence-based representations by 17th October 2026, quoting C25/0740/20/EIA and using the council’s official application record. The September Regulation 19 notice confirms this date for representations on the Environmental Statement and associated proposal.
Relevant planning considerations include the development plan, Planning Policy Wales, design and landscape effects, protected habitats, flood and drainage matters, highway effects, noise, air quality, energy infrastructure, water supply, the Welsh-language context where evidenced and compliance with the EIA process.
Those making representations should identify the planning policy, particular effect and evidence relied on. For large schemes, the distinction between a justified technical concern and an unsupported assumption can be decisive. Consultation is a chance to test the Environmental Statement, not a referendum on whether data centres should exist.
No decision has been verified and there is no basis to describe the project as approved or under construction. The planning authority will have to evaluate the application and material responses before deciding whether permission can lawfully be granted and, if so, subject to what controls.
Related Planning Geek coverage
The debate is part of a wider UK planning question about the location and energy demands of digital infrastructure. Planning Geek has recently covered the Iver data centre and air quality concerns and public objections to a Scottish data centre proposal. These are separate schemes under different planning arrangements.
Primary records: statutory EIA notice and Gwynedd application portal. Reporting and representations: 8th October local reporting and earlier public meeting coverage.
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