For most finance directors, a warehouse roof is a maintenance cost on the balance sheet. For solar PV, it’s close to ideal: large, flat, often unshaded, and above a building that uses most of its electricity in daylight hours.
Done well, warehouse solar panels turn that roof into an asset. They cut your energy costs, fix the price of part of your electricity for 25 years or more, and give you carbon data your customers increasingly expect. This guide covers the questions finance teams ask us most.
Why warehouses suit solar
Warehouse solar panels earn their keep by replacing electricity you’d otherwise buy from the grid. Every kWh you generate and use on site saves you your full unit rate. Every kWh you export earns far less.
Warehouses are a strong fit because they run in daylight, often across several shifts, with a high baseload from lighting, conveyors, MHE charging and refrigeration. A high share of what the panels generate gets used on site, and that’s where the best returns are.
What drives the return
- Self-consumption: the more of your generation you use on site, the better the return.
- Your electricity price: the higher your unit rate, the more each kWh is worth.
- System size and cost: larger systems generally cost less per kWp.
- Roof condition and structure: a roof near the end of its life may need work first, so it’s better to plan both together.
- Grid connection: larger systems need approval from the local network operator, which can affect timing.
Look beyond simple payback
Payback is a useful headline, but it’s not the whole story. Panels typically carry 25 to 30-year performance warranties, so a system that pays back in year five still has two decades of savings ahead of it. When you compare proposals, ask for:
- Lifetime savings and IRR, not just the payback period.
- How much the panels are assumed to lose each year. They lose a little output every year, and the model should show it.
- Budgeted running costs, including an inverter replacement part-way through the system’s life.
- Electricity price assumptions, stated openly so you can test them against your own forecast.
There’s also a risk benefit that rarely appears in the numbers: every kWh you generate is a kWh whose price no longer depends on the wholesale market.
Fix demand first
The strongest solar business cases start with an efficient building. If your warehouse still runs on SON, metal halide or fluorescent highbays, upgrading to LED usually pays back faster than solar and cuts demand straight away. Solar is then sized to your real, lower load, so you’re not buying panels to power wasted energy. CEMA delivers both and can plan them as one programme.
Own or lease?
If you own the building, the full benefit stays with you, and solar can add value to the asset. If you lease, check how long is left and what the lease says about roof alterations. Many landlords welcome solar because it improves the building’s EPC rating, and where an outright purchase doesn’t suit, finance or a third-party arrangement may. We can help you make the case to your landlord.
Funding options
- Outright purchase: the highest long-term return, with savings from day one and access to capital allowances.
- Finance or leasing: spreads the cost, with repayments that can be partly or fully covered by the savings.
- Power purchase agreement (PPA): offered by specialist third-party funders, a PPA means the funder owns the system and you buy the power it generates at an agreed rate. It needs no capital, but the long-term return is lower and contracts typically run for 15 to 25 years. It’s worth comparing against ownership before you commit.The carbon dividend
Retailers and brands increasingly ask their logistics partners for carbon data. On-site solar cuts the emissions from the electricity you buy, the number those customers are asking about, and it gives you measured generation figures you can report. For a 3PL bidding for contracts, that can be as important as the energy savings.
The questions to ask installers
- What proportion of generation will we use on site, and how was that calculated? Did you use our half-hourly data?
- What electricity price assumptions have you made, and what happens to the return if prices fall?
- What Internal Rate of Return and lifetime savings does the proposal show, after running costs and inverter replacement?
- Has the roof structure been assessed?
- Who handles the grid connection application, and what’s the expected timescale?
- What warranties cover the panels, inverters and workmanship, and who stands behind them?
- What monitoring and aftercare are included?
How Neill & Brown Global Logistics put their roof to work
At their Hessle depot, Neill & Brown worked with CEMA to put the roof to work with a commercial solar PV system sized to the site’s daytime demand.
- 36.5% saving on the site’s electricity costs.
- 5.9p/kWh: the fixed cost of the power the system generates, well below grid rates.
- 2.4 tonnes of CO₂ saved every year.
- 5 years 9 months payback, followed by decades of lower-cost power.
Get a costed proposal
A free CEMA site survey gives you a costed, no-obligation proposal with generation estimates, lifetime savings, payback and funding options, ready for your 2027 budget planning.
