Solar for warehouses
Warehouses are among the best buildings in Wales for rooftop solar. Vast, unobstructed roof areas, steel-portal frames that often have spare structural capacity, and significant daytime electricity loads from lighting, conveyors and refrigeration all combine to make payback periods unusually attractive.
We have installed solar on warehouses from 20,000 square feet up to over a million, including distribution units, cold stores, third-party logistics sites, and customer-owned facilities across south, mid, and north Wales.
Roof type matters more than size
The single biggest factor in warehouse solar economics is the roof construction. Steel-clad pitched roofs on modern warehouses are ideal: they support trapezoidal-rail mounting systems with no roof penetration, and the standard 15-degree pitch is close to optimal for Welsh latitudes. Composite panel roofs are also straightforward. Older flat felt or asphalt roofs need careful assessment because the membrane may need replacing before installation, which significantly affects the project economics.
We always include a structural assessment in our proposal because adding several tonnes of distributed weight to a roof is not something to take on trust. For warehouses built to modern industry standards, available spare capacity is usually adequate without strengthening. For older buildings, we may recommend localised reinforcement, which is typically still cheaper than re-roofing or relocating the array.
Matching solar to warehouse load profiles
Lighting, conveyors, dock equipment and refrigerated units drive most warehouse loads. The good news is that these are predominantly daytime loads, particularly in warehouses with day-shift operations, giving very high solar self-consumption. Cold stores running 24/7 still benefit substantially because daytime loads remain higher than overnight.
For warehouses with multiple shifts, including 24/7 logistics operations, we often recommend pairing solar with a modest battery to capture the high midday generation peak and discharge it into the evening shift. This typically lifts annual self-consumption from around 65 percent to above 90 percent, dramatically improving project economics.
Cold storage and refrigeration
Cold storage facilities benefit from solar more than almost any other building type because refrigeration plant runs continuously, and a typical large freezer warehouse consumes several million units of electricity per year. We have several large refrigerated logistics customers where solar covers thirty to forty percent of total demand and battery storage is being phased in to absorb summer generation peaks for winter discharge.
Future-proofing for fleet electrification
Many warehouse operators are now planning HGV fleet electrification, which will dramatically increase site electricity demand. Installing solar today and designing electrical infrastructure with future HGV charging in mind means a smoother transition when fleet replacement cycles bring electric trucks onto the depot.
Frequently asked questions
How much roof area do we need?
A 100kW system needs roughly 500 to 600 square metres of unshaded roof. Most modern warehouses have many times this available, so the limiting factor is usually grid capacity or budget rather than roof space.
Will the panels void our roof warranty?
Reputable mounting systems are non-penetrating on most modern warehouse roofs and so do not affect the roof warranty. We always document compatibility before installation.
Can we sell power to tenants?
Yes, with the right legal structure. We work with landlords on multi-tenant warehouses to structure energy supply arrangements that share the benefits between owner and occupier.
What about flat roofs with bird issues?
Ballasted systems can be configured to leave roof areas accessible for ongoing maintenance including bird deterrents. We design around your existing roof maintenance regime.
Indicative figures for typical Welsh warehouses
A 5,000-square-metre logistics warehouse in south Wales typically supports a 250kW to 400kW system depending on roof orientation and structural capacity. Annual generation of 240,000 to 380,000 units offsets roughly forty to sixty percent of a mid-sized warehouse's consumption, with payback usually achieved within five years on current commercial tariffs. Larger distribution centres routinely host megawatt-scale arrays where the numbers become even more compelling.
For multi-unit estates where one freeholder owns several buildings, we frequently recommend a centralised energy approach where solar generation is shared across units through a private wire arrangement or split metering. This is particularly powerful when one tenant has a heavy daytime load that another lacks, allowing the array to be sized for the combined demand rather than the lowest common denominator.
Health and safety on warehouse roof installations
Working at height on warehouse roofs is the highest single risk in our trade. Every warehouse installation we undertake is preceded by a written risk assessment and Construction Phase Plan covering edge protection, access, fall arrest, and exclusion zones. All our roof teams hold valid IPAF certification for mobile elevated work platforms and current Working at Height training. We coordinate scaffold or MEWP access with the client to minimise impact on operations, including evening or weekend lifts where appropriate.
Working around live warehouse operations
Warehouses very rarely have the luxury of shutting down for solar installation. Pick operations, dock activity and HGV movements continue throughout most installation periods, requiring careful coordination between our site teams and the warehouse operations management. We are experienced at sequencing roof work around dock movements, isolating electrical work to short planned outages, and protecting both our team and warehouse staff during the works. Operational disruption on completed projects has typically been minimal.