Stellium Data Centre

Stellium operates a high-performance computing (HPC) data centre in the UK, designed to support customers across AI, technology, government and other data-heavy industries. In 2025, they partnered with Good Energy to power the site with 100% renewable, hourly matched electricity.

Key stats

• Sector: Data centres
• Designed energy capacity: Scalable to 180 MW
• Annual energy consumption capacity: Over 1TWh
• Hourly matching score: 95.4%

The challenge: renewable power that stands up to scrutiny

In the data centre sector, renewable electricity is increasingly seen as a baseline requirement. And, although they have the capacity to draw up to 180 MW as demand grows, Stellium learnt that REGO backed renewable supply was a key barrier to securing contracts for target customers operating at very high energy volumes, particularly those running continuous, energy-intensive AI and HPC workloads.

REGOs (Renewable Energy Guarantees of Origin) are certificates that show renewable electricity has been generated somewhere on the UK grid over the course of a year. They can be purchased separately from the renewable electricity they relate to, and can be used to match electricity used at any time of the year. This means electricity consumed during periods of high demand – such as evenings or winter months, when fossil fuel generation is often highest – can still be labelled as “renewable” by buying REGOs from surplus generation at other times, such as summer solar output.

As the data centre sector has matured, so too have customer expectations. Stellium has seen a clear shift in RFI and RFP processes, with customers placing greater emphasis on transparent auditability, verified energy sourcing and alignment with their own sustainability targets. To secure more opportunities with their target customer – particularly in the hyperscale space –  and to further their own sustainability commitments, Stellium needed a credible, provable, hourly matched renewable energy supply.

“Our REGO-backed renewable energy supply was no longer holding up to scrutiny. In order to secure contracts with our target customers, we needed to switch to a deep-green hourly-matched energy supply, and Good Energy gave us a credible way to do that.”

Paul Mellon, Operations Director for Stellium

The solution: hourly matched renewables with Good Energy

To meet these expectations, Stellium partnered with Good Energy. With access to hourly matching – where consumption is linked with renewable generation on an hour- by-hour basis – Stellium has gained the additionality and depth of evidence their customers were looking for.

Hourly matching is increasingly recognised as the gold standard for verifying renewable energy sourcing, and is expected to become the minimum acceptable standard as the data centre industry progresses towards net zero emissions.

With Good Energy, Stellium has achieved a 95.4% hourly matching score – well above other UK renewable suppliers. What’s more, they’ve achieved a 75% reduction in carbon emissions compared to standard REGO-based reporting. By sourcing power directly from over 3,300 independent UK generators, Good Energy provides a level of additionality, proof and real-world impact that certificate-based models can’t match.

Generation sources powering Stellium (Reported December 2025):
Onshore Wind: 49.9%
Biomass: 25.1%
Hydro: 13.3%
Biogas: 5.8%
Landfill Gas: 1.0%
Solar: 0.3%

This level of granularity also strengthens Stellium’s position in customer audits. They are now able to report exactly which renewable generation assets have powered the data centre, from technology through to location – providing full visibility of energy provenance and carbon intensity. This approach also aligned with proposed changes to Greenhouse Gas Scope 2 reporting, giving Stellium confidence that its energy strategy would stand up to increasing scrutiny as reporting standards evolve.

Alongside the sustainability credentials, the partnership between Good Energy and Stellium has also delivered on the fundamentals: straightforward processes, strong account management and flexibility to grow without incurring unexpected energy costs like volume tolerance.

As demand for time-matched renewable energy continues to grow across the data centre sector, Stellium is well positioned to meet both commercial and sustainability expectations – transparently, credibly, and at scale; while setting a new industry benchmark for energy sourcing.

“Data centres get bad press for their high, inflexible energy use. But when powered by 100% renewable, hourly matched energy, they can be a force for good – driving additionality that helps make the UK grid greener.

“We’re pleased to have chosen Good Energy as our supplier and to have access to detailed hourly matching data that helps us attract new customers and report clearly to existing ones. We look forward to scaling our business with Good Energy as a partner.”

Paul Mellon, Operations Director for Stellium.

Special thanks

This partnership was brokered by Adam Ben-Said, Director at Energize Gas & Power Ltd, who played a key role in bringing Stellium and Good Energy together and supporting the relationship throughout. Adam is an experienced energy consultant specialising in I&C and mid-market businesses across the UK. He works with organisations to develop tailored energy strategies that go beyond traditional supply, combining renewable energy, onsite generation and flexible procurement to reduce costs, manage risk and support sustainability goals.