Two separate data center proposals are taking shape in Nottinghamshire, England, with Portal Group seeking planning permission for a 20MW facility on a cleared former Eon office site and energy company Uniper pushing to expand development rights at the UK's last decommissioned coal-fired power station.

Portal Group Eyes Former Eon Campus in Annesley

Portal Limited, a company linked to Portal Group, has submitted a planning application to Ashfield District Council to build a data center at Sherwood Business Park outside Mansfield.

The proposed facility would sit on 1.3 hectares along Little Oak Drive in Annesley, on land previously occupied by a three-story office and data center building constructed around 2003 and operated by energy firm Eon. That structure has since been demolished, leaving a cleared brownfield site.

The proposed development would be a two-story building spanning 8,145 square meters and delivering 20MW of IT capacity across four data halls, each rated at 5MW. Portal Group is a provider of managed offices founded in 2000 and is part of the Cannock Group.

The company has a prior history on the site and with Eon specifically. According to an old company presentation, Portal developed a 1MW data center for Eon in 2005. The company also delivered a 5,000 square foot data center for HP at Sherwood Park in 2013.

Portal previously operated a data center division known as Portal Datacentres, which had plans to develop sites across the UK, including a 5MW facility in Birmingham's Aston area that was set to open in 2014.

That site is now occupied by security system supplier Allegion. Planning documents submitted with the current application describe the cleared site as presenting a strategic opportunity to deliver digital infrastructure to support the Sherwood area's commercial and technological needs.

A formal pre-application inquiry was submitted to Ashfield District Council last year, with the council indicating the proposal is acceptable in principle and noting the development would make effective use of a brownfield site.

A Modest but Growing Regional Market

Nottinghamshire has a relatively small data center footprint compared to major UK hubs. Data Center Map lists just five facilities in the city of Nottingham, from operators including nLighten, Iomart, and CWCS, while the town of Mansfield has only one listed facility.

The Portal Group proposal would represent a significant addition to local digital infrastructure capacity. Portal Group's application is not the only development interest in the immediate area.

Property developer Harworth Group has separately indicated plans to build a data center on a former colliery site near Rainworth, a village just outside Mansfield.

Uniper Seeks to Unlock Southern Portion of Ratcliffe-on-Soar for Data Centers

In a separate but parallel development, German state-owned energy company Uniper is seeking to amend the local development order governing the redevelopment of Ratcliffe-on-Soar, the UK's last coal-fired power station, which closed in September 2024 after operating since 1967.

The 270-hectare site, which housed a 2GW plant now being decommissioned and scheduled for demolition by around 2030, sits in Rushcliffe Borough and falls under a local development order originally adopted in 2023.

That order already identifies data centers as an appropriate use for part of the site but confines that use to the northern portion of the land, north of the A453. Uniper is now requesting that the LDO be updated to permit data center development on the southern portion of the site as well.

The rationale is straightforward: the northern section requires extensive demolition work before development can begin, making meaningful data center construction there impossible until approximately 2030.

The southern portion is described in council documents as less constrained and capable of being brought forward more quickly. Council documents state that under the existing order's restrictions, "it is not possible to accommodate a major data center on any part of the site in the short term."

The documents also note that since the LDO was first adopted, market conditions have shifted considerably alongside changes in the political environment, with national momentum now behind accelerating data center development as a driver of economic growth.

Uniper has not disclosed specific details about the number or scale of data centers it is planning for the site. Rushcliffe Borough Council could adopt the updated local development order later this year.

Cllr Neil Clarke, leader of Rushcliffe Borough Council, commented last year that an updated LDO could secure the site's long-term future and allow it to retain local, regional, and national significance.

Clarke said the council wanted to play an active role in maximizing the site's potential and positively shaping its future. Uniper was carved out of Eon in 2016 and is now a German state-owned entity, giving the Ratcliffe-on-Soar redevelopment a tangential connection to the corporate lineage of the Annesley site, where Portal Group is simultaneously proposing its own facility.

Brownfield Redevelopment at the Fore

Both proposals reflect a broader pattern of data center developers targeting previously used industrial and commercial land in the UK.

The Portal Group application repurposes land cleared after the demolition of a building that had served the energy sector, while Ratcliffe-on-Soar represents one of the most prominent post-industrial sites in the English Midlands, seeking a new identity after the end of coal power generation in the country.

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