Summary

• Curtis Hall's Cardiff East Park and Ride proposal includes a temporary energy centre with a maximum generating capacity of 49.9MW.
• The energy centre could operate from July 2028 until approximately July 2033 if the site's planned 150MW grid connection is delayed.
• The developer calls gas generation a worst-case planning assumption, while Welsh ministers are considering whether to take responsibility for the wider planning decision.

A proposed data centre in Cardiff could require its own electricity generation for approximately five years while waiting for a connection to the national grid, creating a dispute over the emissions and infrastructure consequences of building major computing facilities before sufficient power is available.

Developer Curtis Hall has included a temporary energy centre with up to 49.9MW of generating capacity in its plans for the Cardiff East Park and Ride site near Llanrumney. The assessment considers gas turbines operating from July 2028 until approximately July 2033, when the full grid connection is expected under the planning scenario.

The proposed computing campus would ultimately require around 150MW from the electricity network. Curtis Hall maintains that the temporary energy centre is a contingency rather than its preferred permanent power arrangement and says it may be unnecessary if an appropriate connection is delivered earlier.

Opposition to the development has grown among residents, environmental campaigners, and elected representatives. The Welsh Government is considering whether to take over the planning decision, preventing Cardiff Council from granting permission while that issue is resolved.

Temporary generation reflects a longer connection timetable

The wider proposal would replace an existing park and ride facility with three data centre buildings, a substation, supporting infrastructure, and a new road bridge near the A48.

The project has been promoted as an investment opportunity capable of creating construction and technical employment, although the completed computing capacity and commercial benefits remain dependent on planning and infrastructure delivery.

The electricity requirement presents a particular challenge. A grid connection of 150MW would represent a substantial new load, and securing that supply may require work beyond the developer’s site.

Planning documents indicate that the full connection could become available between 2030 and 2034. The temporary energy centre is assessed as operating for approximately five years, beginning in July 2028 and ending around July 2033.

Those dates are planning assumptions rather than confirmation that the energy infrastructure will be built, that gas will be used, or that the grid connection has a final agreed completion date.

The illustrative energy centre includes five gas turbines, a steam generator, and two additional gas turbines held in reserve. Curtis Hall says the technology has not been fixed and that other forms of generation, potentially including fuel cells, remain under consideration.

Fuel cells themselves would need to be assessed according to the fuel used, equipment efficiency, emissions, and operating requirements. Their inclusion as a possible alternative does not establish that the scheme could operate without fossil fuels.

The developer also proposes approximately 40 diesel backup generators for use when the permanent electricity connection is available. Those units would serve a different function from the temporary generation intended to bridge the period before grid capacity is delivered.

Backup equipment may operate occasionally during outages or testing, whereas temporary generation could be required for sustained periods. The two arrangements therefore have different implications for fuel consumption and emissions.

A 49.9MW limit attracts regulatory questions

The proposed temporary capacity sits just below the 50MW threshold relevant to the Welsh consenting regime for electricity generating stations.

Critics have questioned whether the figure was selected to avoid the approval route that would apply to a larger generating facility. Curtis Hall denies that allegation and says the capacity reflects the technical and planning assessment of its proposal.

The company maintains that gas turbines were included in the application because they represented a worst-case scenario for emissions and noise, allowing the environmental assessment to examine potentially demanding operating conditions.

That claim does not resolve the consequences of the proposal. Planning authorities must still determine whether the assessment adequately describes the equipment that could be installed and the effects of operating it.

Nor does being below a particular generating threshold remove the need for planning permission, environmental scrutiny, or compliance with other applicable requirements.

The wider data centre application is itself subject to a separate procedural question. The Welsh Government has issued a holding direction while deciding whether ministers should take responsibility for determining the application instead of Cardiff Council.

That direction prevents the council from granting permission in the meantime, but it is not a final rejection of the project.

Developers and objectors must therefore await decisions about both the appropriate consenting route and the substantive acceptability of the scheme.

Environmental concerns extend beyond electricity

Friends of the Earth Cymru and local representatives have challenged the potential emissions associated with temporary gas generation and the use of diesel backup equipment.

Residents have also expressed concerns about noise, air quality, and the proximity of the development to homes and community facilities. The site adjoins transport infrastructure and land near the River Rhymney, adding local environmental considerations to the assessment.

Curtis Hall disputes suggestions that the proposed facility would cause significant local air quality effects or unacceptable noise. Those statements represent the developer’s position, not a final determination by the planning authority.

The total emissions arising from temporary generation would depend on the equipment eventually chosen, its efficiency, the fuel supplied, and the amount of electricity produced before the permanent grid connection becomes available.

Operating a data centre also requires cooling, networking, and electrical equipment beyond the processors themselves. The resulting demand can vary considerably with the type of computing installed and the facility’s operational design.

Where a project must provide its own electricity, the financial and environmental consequences become part of the data centre’s business model rather than a separate issue for the wider power system alone.

The park and ride site has competing uses

Cardiff East Park and Ride currently serves people travelling to the University Hospital of Wales, including patients and staff. Replacing it has generated concerns about access to healthcare and the availability of convenient alternative transport.

The development proposes a new bridge and road connection, improvements for pedestrians and cyclists, and landscaping around the site.

These works form part of the developer’s case for the project’s wider benefits, but they do not automatically establish that replacing the park and ride would have no adverse effect on its existing users.

The location previously attracted permission for a logistics development. Curtis Hall subsequently changed the proposal to a data centre in response to market demand, introducing different requirements for electricity and supporting infrastructure.

The commercial opportunity therefore needs to be weighed against competing uses of the land and the consequences for people who currently depend on the facility.

Local authorities face similar choices elsewhere as developers seek suitable sites for cloud and AI infrastructure. Proposals can involve substantial private investment while requiring infrastructure, energy, and public services whose availability is determined partly outside the developer’s control.

Computing investment depends on reliable power

Developers may acquire land and prepare facilities long before the electricity network can provide the required capacity. That sequencing creates financial exposure because computing customers need operational capacity rather than merely a completed building.

Temporary generation offers one potential response, but it introduces additional capital expenditure, fuel costs, operating risks, and environmental obligations.

For a 150MW computing campus, a 49.9MW temporary energy centre would not itself provide the full eventual power requirement. The scheme’s operating configuration and phasing would therefore need to reflect the electricity actually available.

Curtis Hall has not confirmed a final temporary generation technology or established that the equipment will be installed. The wider data centre also remains subject to planning decisions.

The immediate questions concern whether an acceptable electricity connection can be secured, what environmental requirements would apply to any interim generation, and whether the proposed redevelopment can proceed on the park and ride site.

The project demonstrates how delays in grid infrastructure can change the design and commercial risks of a data centre before construction begins. Its eventual timetable will depend on resolving those requirements rather than the capacity proposed in the planning application alone.