Solar panels for warehouse and distribution roofs
A warehouse roof is the cheapest generating site your business will ever own. We survey it, model what it can carry, and arrange the design, the grid application and the installation through our MCS-certified partner.
UK wide / capital, lease or PPA / survey first
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How a warehouse solar system works
A warehouse solar system is a rooftop photovoltaic array that converts daylight into electricity your building consumes before it draws anything from the grid. The solar panels sit on the existing warehouse roof, the inverters convert direct current into the alternating current your distribution board already uses, and whatever the site does not consume is exported under a Smart Export Guarantee tariff.
A solar system is not a generator and it is not a substitute for your energy supply contract. Solar panels reduce the volume of energy you buy during daylight hours. Your energy bills fall in proportion to what the building uses on site, which is why the same array produces a very different result on a single-shift unit and a chilled distribution centre running around the clock.
Rising energy costs are what bring most warehouses to solar in the first place, but three things decide whether the project is worth doing: the roof, the load profile and the connection. We look at all three before anyone quotes, and we will tell you when the answer is no.
Why warehouse roofs suit solar better than most buildings
Warehouses carry the largest uninterrupted roof space of any commercial building type, typically at a shallow pitch of six degrees or less, with the structure already designed to carry a snow load. That combination makes the large flat roofs on warehouses unusually cheap to build on: long unbroken runs of panels, few penetrations, no complex shading from neighbouring buildings.
Roof space is the constraint that sets the solar system size on warehouses. A warehouse of 5,000 square metres has room for several hundred kWp once rooflights, walkways, plant and setbacks come out of the gross area. The panels themselves occupy roughly 2.2 square metres for each kWp installed, and a sensible design leaves access around the array rather than filling the deck to the edge.
Warehouses with high energy demand benefit most, and that is the single best predictor of a strong result. A distribution unit with chillers, conveyors, compressors or vehicle charging draws power through exactly the hours the roof is generating, so self-consumption is high and very little is exported at the lower rate.
Illustrative layout for a unit of this size. Your own figures come from the roof survey.
The site assessment we run before any number is quoted
A site assessment is a structural, electrical and commercial survey that establishes what your roof can physically carry and what the resulting system would be worth. It is free, it carries no obligation, and the document is yours whoever ends up installing.
The structural half covers the cladding profile, purlin centres, sheet condition and remaining life, and the additional dead load the frame will take. The electrical half covers your incoming supply, the switchgear, the metering position and the export limit worth applying for. The commercial half is your half-hourly consumption against modelled generation for your latitude.
Asbestos cement sheet is identified rather than worked around. Where a roof is near the end of its life, re-sheeting first is almost always cheaper than removing and refitting an array in five years.
How much energy the roof produces
Annual generation is the product of the solar system size and the energy yield for your location, expressed in kWh for every kWp installed. Across the towns we cover, modelled yield runs from roughly 750 to 950 kWh per kWp a year, and every location page on this site shows the figure for that town alongside its source.
Value follows consumption rather than generation. Electricity you use on site displaces your day rate, which is the highest-value outcome. Electricity you export earns a Smart Export Guarantee rate from your chosen supplier, which is materially lower. The split between the two is the single biggest lever on payback, and it is measurable from your existing meter data rather than assumed.
Battery storage shifts that balance. Adding storage lets a site hold generation from the middle of the day and use it in the early evening, which raises self-consumption on buildings that would otherwise export. Whether that is worth the capital depends on the shape of your load, so we model it as an option rather than selling it as standard.
Modelled yield across the towns we cover
One dot per town, positioned at its centroid and shaded by modelled annual yield in kWh per kWp. Source: EU PVGIS v5.2.
- 704
- 758
- 812
- 866
- 920
- 974
The spread between the best and worst town on this map is 324 kWh per kWp, which is about 46 percent. On a 500 kWp array that is roughly 162,000 kWh a year of difference for the same money spent.
How to measure what a warehouse array saves
The saving from a warehouse solar system is the energy you no longer buy, valued at the rate you would have paid for it. That is the honest way to state it: solar panels do not generate income for most warehouses, they remove a line of energy cost, and the return is the size of that removal set against what the system cost to install.
Two warehouses with identical solar panels and identical roofs can show very different returns. A unit drawing power steadily through the day converts almost all of its generation into avoided energy bills. A unit that runs a single early shift exports the afternoon, and export earns the Smart Export Guarantee rate rather than the day rate. The system design cannot fix a load profile, so we measure yours first.
Returns also move with the price of energy itself. Every business energy contract renewal changes the value of the same kWh, which is why we model the saving against your current unit rate and then show what happens if that rate rises or falls rather than assuming a single number holds for twenty years.
When a warehouse should add battery storage
A battery is a storage system that holds generation the building cannot use at the moment it is produced and releases it later. On a warehouse roof, batteries turn exported energy into consumed energy, which raises the value of every kWh the panels make.
- The load peaks after the array has stopped producing, on an early shift or a late despatch run
- The building shuts at weekends while the roof keeps generating
- Vehicle charging runs into the evening
- Peak demand charges are a visible line on the bill
- The site already consumes almost everything the roof makes during the working day
- The load is steady from early morning to late afternoon
- The lease is too short to see the storage pay for itself
Batteries earn their place on sites with a mismatch between generation and demand: early shifts, weekend shutdowns, or a load that peaks after the solar system has stopped producing. They earn far less on a site already consuming everything the roof makes, where the panels alone do the work and the storage adds cost without adding much saving.
Storage also opens other uses: holding cheap overnight energy, shaving peak demand charges, or supporting vehicle charging. Those cases are worth modelling separately, and we size any battery against twelve months of real data rather than a rule of thumb.
The system design decisions that matter
System design is the process of matching solar panels, inverters and mounting method to one specific warehouse roof. The design fixes the array size in kWp, the string layout, the inverter sizing ratio and the fixing detail for your cladding profile.
Panel choice matters less than most manufacturers would like. Solar panels from any tier-one manufacturer perform within a few percent of each other, and the warranty terms are more informative than the datasheet. Mounting choice matters a great deal, because that is what touches your roof: seam clamps on standing seam, crown fixings on trapezoidal sheet, ballasted frames on membrane.
Inverters carry the shortest life in the system. Plan on replacing them once inside the array's working life and treat that as a maintenance cost rather than a surprise.
The installation process, step by step
The installation process is a fixed sequence that runs from survey to commissioning, and on a commercial roof it is mostly paperwork and access rather than panels.
The connection is the long pole, which is why we submit it early rather than after a contract is signed. Anything above 3.68 kW per phase runs under G99, and the network operator sets the export limit.
Solar installation starts with the survey and the design. Then the grid application: anything above 3.68 kW per phase connects under G99, and the network operator sets the export limit. Then scaffold or mobile access, mounting, module installation, DC and AC electrical work, and the connection into your switchgear. Then commissioning, testing of the solar panels and inverters, the MCS certificate and handover of the operation and maintenance file.
Installation on a mid-sized warehouse is typically a matter of weeks on site once the connection is agreed. The connection is the long pole, which is why we submit it early rather than after the contract is signed.
Tell us about the roof
Send the postcode and the rough footprint. We come back with what the roof can carry, what it would generate against your consumption, and what the three funding routes look like on those numbers.
No survey fee, no obligation. Lenzie Consulting Ltd arranges the survey and passes your details to our MCS-certified installation partner so they can quote.
Questions we get asked before a survey
- What is the 20 percent rule for solar panels?
- The 20 percent rule is a phrase that circulates online rather than a rule in UK legislation or the grid codes. Nothing in the Building Regulations, the DNO connection process or HMRC guidance sets a 20 percent threshold for a rooftop array. What does constrain a warehouse system is the structural capacity of the roof, the usable area once rooflights and plant are excluded, and the export limit your network operator agrees under G98 or G99.
- How much does commercial solar cost per kW?
- Price per kWp falls as the array grows, because the fixed costs of access, design, grid application and commissioning spread across more panels. A quotation covers modules, inverters, mounting suited to your cladding profile, cabling, the DNO application and commissioning. We ask our partner to break the quote into those lines so you can see what varies with roof condition and what does not. We do not publish a price per kWp, because any figure quoted without seeing the roof is a guess.
- Are solar panels worth it on a warehouse roof?
- Solar is worth it on a warehouse roof in proportion to how much of the generation the building uses on site. A unit running chillers, automation or charging through the working day uses most of what the roof produces and displaces electricity at its day rate. A unit that is dark from mid-afternoon exports more, and export is paid at a lower rate under the Smart Export Guarantee. The survey measures your half-hourly consumption against modelled generation before anyone quotes.
- Do you need planning permission for solar panels on a commercial building?
- Roof-mounted panels on a commercial building in England usually fall under permitted development, subject to limits on projection above the roof plane and to the building not being listed or in a conservation area. Ground-mounted arrays and larger installations have their own thresholds. We confirm the position with the local planning authority for your site before the design is finalised.
- What about the roof warranty and the cladding?
- The mounting method is what decides whether a roof warranty survives. Seam clamps grip a standing seam without piercing it, which usually leaves the warranty intact. Trapezoidal sheet is clamped into the crown or through-fixed with a sealed washer, and the right choice depends on the profile, the purlin centres and the age of the covering. Where a roof is near the end of its life, re-sheeting first is usually cheaper than removing and refitting an array later.
- How many solar panels fit on a warehouse roof?
- The number of solar panels a warehouse roof takes is set by the usable area rather than the footprint. As a rule of thumb, each kWp needs about 2.2 square metres of panel, and a modern panel is around 0.45 kWp, so a 5,000 square metre roof with 70 percent usable area carries roughly 1,500 panels and about 700 kWp. The survey replaces that arithmetic with a measured layout, because rooflights, plant, walkways and setbacks vary enormously between buildings.
- Do solar panels work through a British winter?
- Solar panels generate all year, but not evenly. On a typical northern English roof, December output per kWp is roughly a sixth of May output, and every location page on this site shows the month by month profile for that town. That shape is why we size a system against summer daytime demand, then look at whether storage or a revised export limit is worth adding for the darker months rather than oversizing the array.
- Who installs the system, and what does your role cover?
- Installation is carried out by our MCS-certified partner, who holds the contract with you and issues the certificate. Our role covers the survey, the array design, the grid application, the funding comparison and the paperwork in between. We are not the installer, we do not hold MCS certification ourselves, and we say so plainly because the distinction matters when you are checking who is responsible for what.
- Can a warehouse add battery storage later?
- Battery storage can be added later, and on many sites that is the sensible order. Sizing a battery needs real generation and consumption data, and after twelve months of an array running you have both. Designing the electrical infrastructure with storage in mind at the outset costs very little and keeps the option open.