Warehouse PV system design is the engineering layer between your operational data and the financial DCF. Bad design produces oversized systems that export to grid at uneconomic SEG rates, undersized systems that miss the carbon abatement target, or systems that fail structural / sprinkler / DNO compliance review. We design every install from first principles based on your specific building.
What our design service includes
Step 1: HH meter data analysis — 12-month load profile by half-hour, baseload identification, peak demand sizing, weekend dip. Step 2: PVSyst yield modelling — site-specific irradiance from SolarGIS, module temperature coefficients, system loss assumptions. Step 3: Self-consumption modelling — combine load profile with PVSyst generation profile, model by half-hour. Step 4: Structural loading analysis — verify ballast or mechanical fixing against roof reserve. Step 5: Sprinkler clearance integration — LPC standards (1m to deflector, 0.6m high-bay). Step 6: DNO grid connection assessment — G99 capacity check. Step 7: Financial DCF — 25-year IRR, NPV, simple payback, after-tax cash payback, LCOE. Step 8: Audit-ready proposal pack.
Design accuracy benchmarks
Our PVSyst yield modelling is typically within 2% of measured first-year actual generation. Self-consumption modelling from HH meter data is typically within 5% of measured. Financial DCF outturn depends on grid retail tariff trajectory which is the largest uncertainty — we model under conservative assumptions and show sensitivity to higher and lower grid trajectories.
Software stack we use
PVSyst (yield modelling industry standard). SolarGIS (site-specific irradiance database, more accurate than NASA SSE for UK). PV*SOL (alternative cross-check for complex roof layouts). AutoCAD + SketchUp (3D layout integration with structural drawings). Custom Python modelling for half-hourly self-consumption simulation. Each project gets the right tool — we don't shortcut.
Common questions about solar design
Why is design important for warehouse PV?
Warehouse PV is high-capex (£200k-£3m typical) so design accuracy matters. Bad design produces oversized systems (excess export at SEG rates), undersized systems (missed carbon target), or systems failing structural/sprinkler/DNO review. Good design optimises self-consumption ratio, financial IRR, and customer audit value simultaneously.
What's PVSyst and why use it?
PVSyst is the industry-standard yield modelling software for commercial solar PV. Models site-specific irradiance, module temperature coefficients, soiling, shading, mismatch losses, inverter clipping. Output: hour-by-hour annual generation forecast typically accurate within 2-3% of measured outturn.
How do you model self-consumption?
Combine your half-hourly meter data (load profile) with PVSyst half-hourly generation profile. Calculate, for each half-hour, the lesser of generation and load. Sum across the year. Typical accuracy ±5% of measured first-year outturn. Critical for accurate financial DCF.