Commercial parking lots represent some of the most underutilised real estate in the built environment. Solar carports convert that idle space into revenue-generating generation assets — while adding shade, enabling EV charging, and reducing a site's peak demand charges. For retail centres, logistics hubs, and industrial facilities with large surface car parks, carports can be the highest-ROI solar investment available.
The business case for solar carports
Unlike rooftop solar, which competes for space with HVAC equipment, skylights, and structural limitations, parking space is typically abundant, flat, and already owned or controlled by the asset owner. The incremental value proposition of a carport over a standard rooftop system includes:
- Shade for vehicles: Reduced interior cabin temperatures mean lower air-conditioning load at departure — a quantifiable benefit for fleet operators
- Rain protection: Relevant in tropical climates where uncovered parking is operationally disruptive
- EV charging platform: The carport infrastructure creates a natural charging hub — incremental charger installation cost is minimal when wiring is already running to columns
- ESG and planning compliance: Several European jurisdictions now mandate solar carports above a minimum number of parking spaces (France's Agrivoltaism and Parking Law, 2023)
Structure types
Single-post cantilever (most common)
A single row of columns along one side of the parking bay, with a cantilever roof structure. Allows maximum vehicle access width, minimal column footprint, and clean visual appearance. Best for single-bay rows up to 5–6 m span. Requires robust footings due to cantilever moments.
T-structure (double cantilever)
A central column row supporting bilateral cantilever arms — covers two rows of parking from a single column line. Cost-effective for double-row parking layouts; reduces civil works per kWp by 30–40% vs single-post. Column spacing of 8–12 m typical.
Full portal frame
Columns on both sides, beam across the top. Suitable for wide-span requirements (delivery vehicles, large SUVs) or high-wind-load zones. Higher steel weight than cantilever but simpler structural analysis and stiffer in lateral wind.
Key design parameters
| Parameter | Standard cars | SUVs / light commercial | Vans / trucks |
|---|---|---|---|
| Min clear height | 2.1 m | 2.4 m | 2.7–3.0 m |
| Bay width (per space) | 2.5 m | 2.7 m | 3.0 m+ |
| Module tilt angle | 5–15° (low tilt for minimal wind load and waterproofing); 20–30° where self-cleaning and yield optimisation is prioritised | ||
| Modules per space | 1.5–2 modules | 1.5–2 modules | 1–1.5 modules |
| Typical kWp per space | 0.8–1.1 kWp | 0.8–1.0 kWp | 0.5–0.8 kWp |
Drainage and waterproofing
Low-tilt carport roofs (5–10°) require careful waterproofing: module frame-to-frame gaps must be sealed or overlapped, and guttering must run along the lower edge to capture rainfall. In high-rainfall climates, drainage capacity must be sized for 1-in-50-year storm events — undersized gutters overflow onto vehicles and cause complaints. Many carport structures use aluminium extrusion systems that integrate guttering as part of the rafter profile.
Structural loading considerations
Carport structures carry solar modules (35–40 kg/m²), snow load (site-dependent; in European/CIS climates 0.5–2.0 kN/m²), and — critically — wind load. Wind uplift on a low-pitched carport in an exposed open-plan car park can reach 2–3 kN/m². Wind is typically the governing design load for carports, not gravity. Columns and footings must be sized accordingly, and structural engineers often specify poured concrete footings 1.0–1.5 m deep and 500–800 mm diameter for single-post cantilever structures.
Integration with EV charging
The most compelling carport projects integrate Level 2 AC chargers directly into the column structure. The carport DC-to-AC conversion feeds into a distribution board at the carport edge, which then powers chargers along each column. A 100-space carport at 85 kWp can generate approximately 120–150 MWh/year — enough to power approximately 40–50 EV chargers at 7 kW average utilisation (charging 6–8 hours/day). For higher-power DC fast charging, a separate grid connection and optionally a BESS is needed.