Summary
EvoEnergy delivered an 8.06MWp rooftop solar PV installation at Aldi’s Bardon Distribution Centre in Leicestershire, a 1.3 million sq ft facility described by Aldi as Britain’s largest supermarket warehouse.
Comprising 18,976 Trina 425W panels, the system is forecast to generate 6,773,600 kWh of renewable electricity each year and save approximately 1,402,474 kg of CO₂ annually.
The Challenge
Aldi’s Bardon Distribution Centre is one of the UK’s most significant food retail logistics facilities. The site comprises five linked buildings and is designed to support nearly 350 stores, creating a high-demand operational environment where efficiency, resilience and continuity of supply are essential.
The brief was to deliver a large-scale rooftop solar PV system capable of supporting the site’s low-carbon infrastructure and reducing reliance on grid electricity. However, the project was far more complex than a standard commercial rooftop solar installation.
Aldi’s original electrical requirement for the site was around 20MW import and 10MW export. The grid offer ultimately provided only 1MW import for an initial 2–3 year period, with no generation allowed and a high likelihood of longer-term import and export constraints. For a facility of this size, that created a significant operational and commercial challenge.
A conventional rooftop PV system or standard export limitation approach would not provide the level of control, speed or protection required. The site had to be developed with the expectation that off-grid, or microgrid, operation could be required for part or all of the facility, meaning the PV system would need to work safely within a more complex electrical environment.
A key challenge was the need for the PV system to operate in parallel with diesel generation as the grid-forming element, without battery storage. This is technically unusual. In most diesel and PV microgrid systems, batteries act as an energy buffer, absorbing sudden changes in load or generation. At Bardon, batteries of sufficient scale were cost-prohibitive and physically difficult to locate, so a different engineering approach was required.
Without advanced control, large-scale PV operating alongside diesel generators can backfeed rotating generation sets. This can cause generator stalling, alternator damage, unstable voltage and frequency, loss of supply and potentially serious equipment failure. The system therefore had to be engineered to generate renewable electricity at scale while protecting the facility, the generators and the solar asset.
The site also presented major practical delivery challenges. Lifting materials and equipment to the roof was difficult and required specialist cherry pickers. Inverters originally intended for internal installation were relocated to the roof and housed in specialist containers. The programme, originally expected to take 9–12 months, extended to around 24 months, creating complex sequencing between contractors and suppliers.
One of the most demanding installation challenges was the routing and pulling of approximately 500m of DC armoured cable across rooftop service boxes. Original contractor layouts were not accurate, so cable routes had to be redesigned. Specialist designers and engineers were needed to distribute cable weight across multiple roof areas, manage drops between roof levels and design specialist cradles to support the cable routes safely.
Our Solution
EvoEnergy delivered a complete 8.06MWp rooftop solar PV system comprising 18,976 Trina 425W panels. The installation places Bardon among the UK’s largest single rooftop solar PV systems and turns a major commercial roof into a long-term renewable energy asset.
To overcome the site’s electrical constraints, we developed a distributed PV control solution capable of supporting the solar system across the site’s 11kV private network. This control-led approach was central to making the project viable, allowing the PV system to operate safely in a constrained environment where standard grid-connected solar controls would not have been sufficient.
The control architecture comprises five main control elements: one panel at each of the site’s four 11kV substations and one central unit at the grid interface point. These are connected through a fibre-optic communications network across distances of up to 1,200m.
The system monitors a wide range of signals, including circuit breaker states, generator signals, inverter feedback, import and export flows, fire alarm states, DNO safety signals and local power flows. This gives the system the visibility needed to manage generation safely across a physically distributed and electrically complex site.
A typical G100 export limitation system may operate with response times of around one minute. At Bardon, the system samples key control inputs every 200ms and can respond in under one second. This rapid response was essential because generator backfeed damage was assessed as possible within 1–5 seconds if minimum load thresholds were breached.
When PV generation is too high for the available load, the system curtails inverter output. If curtailment fails, or if a critical communication or monitoring blind spot is detected, the system isolates the PV safely to protect the generators, the facility and the solar asset. Heartbeat signals are sent every 200ms to confirm that critical devices remain active and healthy, even when they are not actively changing state.
The solution also allows each control element to operate independently or as part of the wider networked system. This provides flexibility for normal on-grid G99/G100 operation, while also supporting the off-grid PV interfaces required by the site’s potential microgrid operation.
On site, our project team adapted to changing requirements and complex construction conditions. The relocation of inverters to the roof required specialist containers, while cable routing was redesigned to respond to inaccurate original layouts. Specialist engineers developed revised routes, distributed load across multiple roof structures and introduced cable cradles to support safe, compliant installation. Throughout the project, our team coordinated closely with other contractors and suppliers to manage sequencing across an extended programme, ensuring the installation could progress safely while remaining aligned with the wider construction and electrical works.
The Result
The completed system is a landmark commercial solar installation that demonstrates what can be achieved when renewable energy is treated as critical building infrastructure rather than a bolt-on technology.
The 8.06MWp rooftop solar PV system is forecast to generate 6,773,600 kWh of renewable electricity each year, saving approximately 1,402,474 kg of CO₂ annually. Aldi has publicly stated that the Bardon site features around 19,000 rooftop solar panels which, at times, will be able to generate all the electricity required by the facility.
The project supports the low-carbon operation of one of the UK’s most important food retail logistics assets, helping Aldi reduce the carbon intensity of a high-demand distribution environment while improving the productive use of available roof space.
From a technical perspective, Bardon proves that large-scale rooftop solar can be delivered on complex, grid-constrained sites where conventional approaches may not be sufficient. The project combined major PV deployment with advanced control engineering, 11kV private network integration, fibre-optic communications, diesel generator interface protection and fast-response fail-safe logic.
From a delivery perspective, it demonstrates EvoEnergy’s ability to manage complex rooftop logistics, specialist lifting, changing design requirements, extended programme sequencing and challenging cable routing without compromising safety or the overall project objective.
Aldi Bardon is more than one of the UK’s largest single rooftop solar PV installations. It is a blueprint for how high-demand commercial buildings, logistics centres, cold storage facilities and manufacturing sites can unlock meaningful renewable generation even where grid constraints create significant barriers. The project shows that, with the right engineering, commercial solar can support operational resilience, reduce carbon emissions and help major businesses future-proof their energy infrastructure.