Further details about a government-backed plan to build a £3.75bn hyperscale datacentre on a plot of Green Belt Land, neighbouring the South Mimms service station in Hertfordshire, have emerged, following the publication of the full planning documents for the proposed build.
The project is being overseen by an organisation incorporated in July 2022 called DC01UK.
The company is a joint venture between renewable energy consultancy Chiltern Green Energy and building developer Griggs Homes, and the project is the first they have undertaken together.
This is not the first datacentre project Griggs Homes has been involved in, though, as the firm previously secured planning for the development of a 30,000 square metre datacentre in 2022 on the A41 in Bushey, Hertfordshire that was sold to colocation firm Ark Data Centres.
A series of documents in support of the DC01UK project were submitted on 9 September 2024 to the Hertsmere Borough Council planning office, seeking outline planning permission for the project.
This essentially means DC01UK has asked the council if its speculative plan for the site would be considered, in principle, an acceptable use of the land in question.
Digging into the planning documents
The planning documents confirmed DC01UK is seeking permission for a phased development “comprising of” up to 187,000 square metres of datacentre space, including ancillary offices, an internal plant and equipment, and a substation.
If DC01UK is successful in getting its outline planning permission application approved, responsibility for the construction of the datacentre would fall on an unspecified “end-user” who will have the “opportunity” to tailor the design of the facility to their needs.
The planning documents confirm that several parties have been approached already with a view to taking over the site, with the developers known to be courting both colocation companies interested in leasing the site out and members of the hyperscale community, too.
“The applicant [DC10UK] is not an operator of datacentres,” the document stated. “As a consequence, an outline planning application has been submitted to establish the acceptability of the principle of development.”
If the local council deems the project to be acceptable, it will then fall on this end user to submit their own specific plans for the site, in the hope of getting their bespoke datacentre development project approved.
“Details of access, appearance, landscaping, layout and scale [will be] reserved for later determination,” the document stated.
Balancing economic growth with local pressures
The Hertsmere Borough Council planning portal confirmed that five objections have already been raised about the plans since they were submitted on 9 September 2024, while an additional eight submissions in support of the project have also been received.
A planning document, seen by Computer Weekly, states that a series of concerns about the impact the build will have on the area’s Green Belt Land, as well as on its biodiversity and local traffic levels, were also raised with developers, since details of the project were publicised in early September 2024.
Several days after DC01UK’s planning documents were submitted to the local authority, a government press release dropped regarding the Department of Science, Innovation and Technology’s (DSIT) decision to classify datacentres as critical national infrastructure (CNI).
Much of the press release focused on the added protection CNI status would confer on operators, in terms of evading cyber attacks.
However, it also said adding datacentres to the UK’s CNI regime would give developers more confidence when investing in large-scale server farm builds, with the one DC01UK is plotting cited as an example of the type of datacentre development the government is looking to attract.
“The huge, £3.75bn private investment in Hertfordshire is a vote of confidence in those plans, and a clear example of my determination to ensure technological advancements are helping to grow our economy and create wealth across the country,” said technology secretary Peter Kyle.
Residents assured
Despite the government’s apparent championing of the project, Hertsmere Borough Council leader Jeremy Newmark moved to assure residents that any concerns they have about the project will be taken into account.
Although his comments seemed to suggest the project does have a degree of local-level support already.
“Of course, the application is subject to the planning process during which we will, as always, listen and speak to residents about the plans, and a public consultation on the proposals will be held for people to give their views,” he said. “I am certain that local people will realise the benefits of the scheme. It has my full support.”
In the meantime, it’s worth noting the Labour government is consulting on plans to loosen the planning rules governing datacentre developments, as a means of generating more economic growth in the UK.
The proposals would reclassify datacentres as “nationally significant infrastructure projects”, which would mean server farm builds would no longer need local council approval to proceed.
Instead, datacentre developers would submit details of their projects to the Planning Inspectorate for appraisal, who would then refer them on to the secretary of state to decide whether or not they should go ahead.
Fast-tracking projects
The theory is that shaking up the planning rules for datacentres in this way will make it easier for the government to fast-track projects that may have previously got turned down by local council planning departments.
As previously reported by Computer Weekly, the government has already placed under review two projects that the previous administration blocked because they were supposed to be constructed on Green Belt land.
The DC01UK plans have been submitted ahead of the consultation on reclassifying datacentres as “national significant infrastructure projects” closing on 24 September 2024. However, if the government does press ahead with its proposals, it could make life a bit easier – from a planning permission sign-off perspective – for whoever takes over the site. Particularly, as DC01UK is targeting a 2026 submission date for the follow-on planning applications from whoever takes over the site.
For the objectors to the DC01UK build, these developments might make it sound like the project will proceed, unabated, whether they like it or not.
However, Andrew Jay, head of datacentre solutions, advisory and transaction services for Europe, the Middle East and Africa at CBRE, said datacentre operators are sensitive to how they might be perceived in situations like this.
“The datacentre industry absolutely recognises that this isn’t about them riding roughshod over people or places, and there is a symbiotic element to this, of course, because with a datacentre comes huge investment,” he told Computer Weekly. “There is absolutely hundreds of millions and billions of pounds of investment into UK Plc [coming from datacentres], and that’s really positive.”
Community projects
On this point, operators will sometimes add in commitments to their planning applications to landscape the areas around where their datacentres will be sited, or offer to fund other community projects.
In some instances, operators have also funded improvements to local electricity substations that the whole region will benefit from, as an acknowledgement that their activities will put additional pressure on the local grid.
Another way operators are increasingly seeking to do this is by investing in heat exchangers when building out their facilities, so that the waste warm air their activities generate can be put to use in district heating systems for the benefit of nearby homes and business, added Jay. “There aren’t many new datacentres being built now where people aren’t at least considering how to put their surplus heat to use,” he said. “And that is an absolutely perfect example of how the industry is very keen to be seen as a good neighbour.”
It’s worth noting that the DC01UK planning documents confirm that heat reuse is not a community benefit this development will be pursuing, but there is a lot of talk in the documents about the economic benefits the project will bring to the local area in both the short and long-term.
According to a 45-page economic benefits document submitted on DC01UK’s behalf by engineering company Stantec, a “new build datacentre of the type and scale proposed” would create an average of 100 jobs on site, once the first phase of the build is complete.
And this number will double from 2031, once “all three datacentre buildings are operational” and each one will generate a gross value added (GVA) of £192,555 for the local economy.
“These workers will generate an estimated £38.5m in GVA to the local economy once all three datacentre buildings are operational,” the document added. “Due to its location, it is reasonable to assume that the proposal would predominantly benefit the data economy across the wider South East … [and] this could result in the indirect benefits of the South Mimms datacentre amounting to £906.8m GVA per annum and supporting 10,993 jobs (once fully operational).”
Attracting interest
While it remains to be seen how the outline planning application for the project will fare, a document submitted by real estate consultancy Knight Frank, as part of the planning application bundle, said the site has already attracted interest from two colocation providers about taking it over.
“[Knight Frank has] held detailed discussions with two UK-headquartered datacentre colocation operators who would commit to occupying the entire site and are confident in securing a 100% pre-let commitment,” the document stated.
The Knight Frank document also goes on to describe the site as a “prime datacentre location” due to its proximity to “two critical datacentre development fundamentals: power and fibre.”
Where the former is concerned, Knight Frank claims the site has a reservation of 400MVA coming direct from the National Grid, which is due for delivery in October 2029. This is the same year DC01UK is aiming for the facility to be up and running.
For now, it’s simply a case of waiting to see how DC01UK’s plans are received by the local planning office, but also how the new government’s proposals to ease the planning barriers and elevate the status of the UK datacentre industry further plays out.
