Office Solar Case Study
Manchester multi-let HQ — 480 kWp + 215 kWh battery
Manchester multi-let HQ — 480 kWp + 215 kWh battery
An estates manager at a 12,000 sqm grade-A office in the M2 postcode came to us with two problems: a 2018 EPC at ‘B’ that had re-rated to ‘D’ under SAP 10.2, and three FTSE-100 tenants asking for Scope 2 carbon disclosure in their next service-charge cycle. Our team modelled the half-hourly meter data across 14 sub-meters, designed a 480 kWp roof-mounted system with 215 kWh battery storage, and structured cost recovery via a Service Charge Code 2018-compliant pass-through.
The numbers
| Metric | Value |
|---|---|
| System size | 480 kWp + 215 kWh BESS |
| Panel count | 885 |
| Annual generation | 442,000 kWh/year |
| Annual saving | £148,000/year |
| Simple payback | 5.4 years |
| Annual CO₂ saved | 101 tonnes |
| EPC uplift | D → B (8-point gain) |
| Completion | Q1 2026 |
Project approach
The starting point on this project, as with every commercial office install we deliver, was the customer’s half-hourly meter data. Without it, sizing decisions are guesswork — the difference between a 70% self-consumption design and a 30% one usually comes down to load profile rather than roof area or panel choice. We pulled twelve months of half-hourly consumption from the customer’s DNO, ran the demand profile against PVSyst yield models for the building’s specific latitude, roof pitch, and shading characteristics, and modelled three scenarios: PV-only at 60% coverage, PV-only at 80% coverage, and PV plus battery at 95% coverage.
The scenario that won on NPV-over-25-years was the middle option — PV-only sized to deliver around 80% of annual demand, accepting a slight summer-export tail under SEG rather than over-sizing battery for marginal additional self-consumption. The economics of battery storage continue to shift as cell prices fall and capacity-market revenues rise, but for this specific building’s load shape and electricity tariff structure, the unbatteried design produced the best 25-year IRR.
Roof, structural, and electrical
The roof was assessed for structural loading per BS EN 1991-1-1 (dead loads) and BS EN 1991-1-4 (wind loads). Ballasted east-west arrays were specified to preserve membrane warranty and avoid roof penetration. Two string inverters were sized at 110% of array DC capacity to capture clipping-edge gains during cloudy summer peaks. Cable routes ran via existing rooftop plant rooms to the main switchroom, avoiding occupied office floors entirely.
Grid connection went via G99 with the local DNO — application submitted six months ahead of planned install date, with full export and import limits agreed at the connection offer stage. Commissioning followed IEC 62446 with full string-level performance documentation handed to the customer’s facilities team alongside an O&M manual covering quarterly visual inspection, annual cleaning, and 5-year inverter warranty management.
Compliance, EPC and reporting
The system was specified to MCS Commercial standards with NICEIC electrical certification. RECC-compliant customer documentation was provided. The EPC was re-rated after commissioning with the install captured under SAP 10.2 methodology — delivering the D → B (8-point gain) uplift recorded above and locking the building’s MEES 2030 compliance position.
For the customer’s Scope 2 emissions reporting, we provided a disclosure pack containing location-based and market-based emissions calculations, REGO certificate handling guidance, SECR-ready narrative for the annual report, and CDP Climate Change response text pre-populated for solar-related questions.
What the customer said
“The MEES 2030 risk register went from red to green overnight. Our three FTSE tenants signed early lease renewals with green-lease addenda by the end of the year.”
Could your office building deliver similar results?
The economics on this case study aren’t unusual for a well-designed office solar install in 2026 — payback inside 7 years, double-digit IRR over 25 years, meaningful EPC uplift, and Scope 2 reduction documented to FTSE-tenant audit standards. What varies between offices is the specific load shape, roof area, electrical infrastructure age, and tenancy structure.
The fastest way to understand your specific economics is a free desk feasibility study. Send us half-hourly meter data and a roof plan, and we’ll model your building specifically within 7 working days.