Key Takeaways
- Warehouses are ideal for solar PV due to large flat roof areas and high daytime energy consumption
- A structural survey is essential — solar panels add approximately 12–15kg per m² of load
- Typical warehouse systems (50–250kW) pay back in 4–6 years with high self-consumption
- Battery storage can increase self-consumption above 80% for facilities with evening operations
- Wire Now delivers commercial solar installations across London, Hertfordshire, and Essex
Is My Warehouse Roof Suitable for Solar Panels?
Warehouses and industrial units are among the best candidates for commercial solar PV due to their large, unobstructed roof areas and high daytime electricity consumption. However, several factors need assessment before installation can proceed.
Structural capacity: Solar panels and mounting equipment add approximately 12–15kg per m² to the roof. A structural engineer must confirm the roof can support this additional load, particularly for older buildings or those with lightweight roof constructions. Wire Now arranges structural surveys as part of our feasibility process.
Roof material and condition: Solar mounting systems are compatible with most commercial roof types including profiled metal sheeting, flat membrane roofs, and standing seam roofing. The roof should be in good condition with at least 20 years of remaining life to match the expected panel lifespan.
Orientation and pitch: South-facing roofs generate the most energy, but east-west configurations are also effective and can provide a more even generation profile throughout the day. Flat roofs use angled mounting frames to optimise panel tilt.
Shading: Adjacent buildings, roof-mounted equipment (HVAC units, flues, antennas), and parapets can all create shading that reduces generation. A shading analysis identifies any issues and informs the system layout.
Asbestos: Older industrial buildings may have asbestos-containing roof materials. An asbestos survey is required before any roof work can begin.
What Size System Does a Warehouse Need?
System size depends on your electricity consumption and available roof space. Typical warehouse installations:
- Small warehouse (500–1,000m² roof): 30–50kW system
- Medium warehouse (1,000–3,000m² roof): 50–150kW system
- Large warehouse/distribution centre (3,000m²+ roof): 150–500kW system
The aim is to size the system so that 70%+ of generated electricity is consumed on-site. This maximises the value of every unit generated, since self-consumed electricity displaces purchased electricity at full retail rate, while exported electricity earns only the (lower) export tariff.
What ROI Can a Warehouse Expect from Solar?
Warehouses typically achieve strong ROI because of their high daytime consumption profile — lighting, refrigeration, loading equipment, and office areas all consume electricity during peak generation hours.
For a typical 100kW system on a medium warehouse:
- Self-consumption ratio: 65–80%
- Annual generation: approximately 85,000–95,000 kWh
- Annual savings: £15,000–£25,000 (depending on electricity rate)
- Payback period: 4–6 years
- System lifespan: 25–30 years
These figures improve further if you operate evening shifts or add battery storage.
Should I Add Battery Storage?
Battery storage is worth considering if:
- Your facility operates outside daylight hours (evening shifts, overnight operations)
- You're on a time-of-use tariff with peak/off-peak pricing
- Your DNO has limited export capacity, forcing you to curtail generation
- You want backup power capability for critical operations
A battery system stores excess daytime solar generation for use during evenings or peak-rate periods. For a warehouse generating 100kW, a 50kWh battery system can increase self-consumption from 70% to 85%+, significantly improving ROI.
Battery costs have decreased by approximately 40% over the past three years, making the combined solar-plus-storage proposition increasingly attractive.
How Wire Now Can Help
Wire Now is an MCS-certified, NICEIC-approved contractor with experience delivering solar PV installations for warehouses and industrial units across London, Hertfordshire, and Essex. We provide:
- Free site survey including roof assessment and structural review
- Detailed feasibility report with ROI projections
- G99 DNO application and grid connection management
- Professional installation by directly employed engineers
- MCS commissioning certification
- Optional battery storage integration
Get a free solar feasibility assessment →
Part of our [Commercial Solar PV Guide](/blog/commercial-solar-pv-installation-guide-uk) series.
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