Solar Panels for Warehouses & Logistics Buildings

As a rough planning figure, a modern portal-frame roof supports somewhere around 100-130 kWp of PV per 1,000 m² of usable, unshaded roof plane, before you deduct rooflights, gutters, plant, walkways and edge exclusion zones. But roof capacity is the wrong starting point. We size to your daytime electrical baseload from half-hourly data, because a unit you consume is worth several times a unit you export under a Smart Export Guarantee tariff. Harris Parts is a good example: 154 kWp plus 64 kWh of battery storage, sized around the site's daytime machinery load and documented to save around £16,000 a year. Filling every square metre of a big shed roof usually lengthens the payback rather than shortening it, unless you are pairing it with battery storage or heavy EV fleet charging.

Usually yes, but it must be checked rather than assumed. Portal-frame sheds are deliberately light and the purlins, not the main frame, are normally the limiting element. SCI advisory note AD 541 highlights that real PV systems often weigh around 0.35 kN/m² where designers assumed 0.15 kN/m², and the array has to be assessed alongside imposed and snow loading. We commission a structural appraisal on older buildings, long purlin spans, or roofs that have already been re-clad or had plant added. Occasionally the outcome is that only part of the roof can be loaded, or that localised purlin strengthening is needed. We would rather tell you that at survey than after mobilisation.

It still stacks up, but the design changes. Overnight MHE charging sits outside the generation window, so it cannot be offset directly by daytime solar. Two routes work. First, look at whether charging can be shifted or split. Many li-ion MHE fleets opportunity-charge during shift breaks, which moves a meaningful slice of that load into daylight. Second, size the array to the loads that genuinely are daytime (high-bay lighting, conveyors, compressors, refrigeration, offices) and use battery storage to carry midday surplus into the evening charge window. We model both options against your actual half-hourly data before recommending a system size.

Yes, but the lease governs it. The array is an alteration to the landlord's building, so you will need a licence to alter, and you need a written position on three things: who owns the system, whether reinstatement is required at lease end, and how it is treated at rent review and in dilapidations. Term length is the practical test, a residual term comfortably longer than the payback is what makes it work. Where the term is short, the alternative is a landlord-funded array with the tenant buying the power, which is increasingly attractive to landlords because on-site renewables improve the EPC rating ahead of tightening non-domestic MEES requirements for larger commercial buildings.

In England, most commercial rooftop solar is now permitted development. The 1 MW generation cap on non-domestic rooftop installations was removed by an amendment to the GPDO that took effect on 21 December 2023, which was the change that finally opened up large distribution roofs. Conditions still apply: projection above the roof plane, siting on listed buildings and in conservation areas, and the requirement to remove the equipment when no longer needed. The bigger consent hurdle is almost always the grid, not the council: every commercial array needs a G99 connection application to the DNO, and that is where programme risk sits.

Often not, and you should plan for that. In a network area as heavily loaded as the West Midlands, G99 offers for large rooftop arrays frequently come back with an export limit, enforced by an export limitation device, rather than unrestricted export. On a self-consumption-led design this is rarely a problem, because the value is in displacing imported power at the full delivered rate anyway. It only becomes material if you were relying on selling large summer surpluses. We submit the G99 application early and design to a realistic export position rather than assuming the best case, because DNO response times are the most common reason warehouse solar projects slip.