Why your retail and manufacturing customers are asking about your Scope 2 emissions
GHG Protocol market-based accounting allows companies to report Scope 2 emissions based on the actual electricity product they purchase — not the grid average. A warehouse consuming 1 GWh/yr from the grid at 233 g CO2e/kWh generates 233 tCO2e/yr in Scope 2. The same warehouse consuming 700 MWh self-generated solar and 300 MWh grid would report 70 tCO2e/yr — a 70% reduction. This is directly material to your customers Scope 3 Category 1 (purchased goods) or Category 4 (upstream transportation and distribution) emissions. Tesco, M&S, ASOS, JLR, Unilever, and Sainsbury's now request Scope 2 data from warehousing suppliers as part of annual Scope 3 reporting.
How REGO registration works for self-generated solar
Renewable Energy Guarantee of Origin (REGO) certificates are issued by Ofgem for renewable electricity generation. For self-generated solar PV: the system must be registered on the Ofgem Renewables and CHP Register; one REGO is issued per MWh of verified generation; REGOs can be retained (for your own GHG reporting) or sold on the REGO market. Registration process: Ofgem registration requires meter data submitted quarterly; verification against half-hourly generation meter; annual REGO issuance aligned to the REGO year (April-March). The key point: you do NOT need to sell REGOs to claim the self-generated electricity is renewable in your GHG inventory. REGOs are required only if you want to transfer the renewable attribute to a customer.
Reporting self-generated solar in SECR
SECR applies to UK-quoted companies, large LLPs, and large unquoted companies (turnover above £36m, above 250 employees, or balance sheet above £18m). For self-generated solar in SECR: Location-based method — self-generated solar reduces location-based Scope 2 by the avoided grid consumption (consumed solar kWh multiplied by grid emission factor). Market-based method — self-generated solar attributed at zero g CO2e/kWh (no REGO required for own use). Both methods are acceptable under SECR. Your SECR report should state: total electricity consumption (grid + self-generated), self-generated solar amount, method used, and resulting Scope 2 figure.
Satisfying Tesco, M&S and JLR Scope 3 supply chain audits
Each major retailer and manufacturer has its own supply chain sustainability audit process. Tesco: uses a CDP-based questionnaire submitted annually through the Tesco Supplier Excellence portal. Requires Scope 2 disclosure using market-based method. M&S: Plan A supplier engagement — annual survey requires energy intensity and renewable percentage disclosure. JLR: Supplier sustainability scorecard — requires Scope 2 emissions data and year-on-year reduction trajectory. JLR specifically accepts REGO-backed self-generated solar as evidence of Scope 2 reduction. ASOS: Annual Fashion Transparency Index disclosure — requires Scope 1+2 data at facility level.
The SECR/GHG reporting timeline for warehouse solar
Installing solar PV in Q3-Q4 2026 means your first full SECR reporting year with solar contribution is April 2027-March 2028, reported in the 2028 annual report. For supply chain audit purposes, partial-year benefits are reportable from installation date. A system installed September 2026 generates approximately 7 months of generation data (Sept 2026 - March 2027) reportable in SECR year ending March 2027. For customers demanding 2026 Scope 3 data: partial-year data is accepted — even 3-4 months of solar generation data demonstrates commitment and quantifiable progress.
UK warehouse solar economics 2026 — at a glance
UK commercial solar PV for warehouses has fundamentally changed economically between 2019 and 2026. Three structural shifts drive current 4-6 year paybacks: grid electricity has nearly doubled from 12-15p/kWh blended day rate in 2019 to 16-26p/kWh in 2026, with peak Time-of-Use rates now reaching 28-35p/kWh during 16:00-19:00 evening peak; battery system cost has fallen from £700-£900/kWh installed in 2020 to £250-£450/kWh in 2026; and 100% Annual Investment Allowance up to £1m of capex per year delivers immediate 25% corporation tax relief on solar capex. A typical 1 MW warehouse rooftop solar install costs £700,000-£800,000, generates 870,000-950,000 kWh per year, displaces £155,000-£180,000 of grid electricity annually, and pays back in 4-5 years before tax — 3-4 years after AIA tax shield.
Compliance pressure driving warehouse solar adoption in 2026
Four converging UK compliance forces make warehouse solar effectively necessary by 2030. (1) MEES EPC B by April 2030: all commercial property must achieve EPC rating B or better to be let. Solar PV adds 5-15 EPC points and is often the most cost-effective compliance route for warehouse stock currently at EPC C-D. (2) ESOS Phase 4 (December 2027 deadline): Energy Savings Opportunity Scheme requires large UK businesses to commission energy audits and implement or document rationale for solar recommendations. (3) SECR reporting: mandatory Streamlined Energy and Carbon Reporting requires Scope 1+2 emissions disclosure in annual reports — solar PV directly reduces reported Scope 2 figure. (4) Customer Scope 3 mandates: Amazon Climate Pledge, Tesco Net Zero, M&S Plan A, Sainsbury's Plan for Better, John Lewis Net Zero, JLR/Stellantis Tier-1 supplier programmes all flow Scope 3 supplier requirements through contract weighting and CDP/EcoVadis reporting. 3PL operators and owner-occupied warehouses serving these customers face direct commercial consequences if they fail to demonstrate verifiable renewable generation by 2027-2030.
How we model warehouse solar — half-hourly meter data, not assumptions
Every warehouse solar feasibility we deliver starts with your 12 months of half-hourly meter data and a roof drawing. Standard online solar calculators use generic per-sqft estimates that miss the operational pattern variation driving 30-40% of total payback difference. Our methodology: PVSyst yield model calibrated for your specific roof orientation, tilt and shading; self-consumption profile derived from your actual half-hourly demand at 15-minute resolution; 25-year DCF with monthly cashflow granularity; capital allowance schedule (AIA + ECA where applicable); grant funding scenario where eligible (IETF Phase 3 for manufacturers above 1 GWh/yr); SEG export tariff and REGO income; O&M cost schedule; sensitivity analysis on grid tariff inflation, self-consumption ratio, capex per kW and discount rate. Output: simple payback, after-tax payback, IRR, NPV at 4%/6%/8% discount rates, and 25-year cumulative return. If the numbers do not work for your specific site, we say so — we have walked away from over 60 projects since 2020 where economics did not justify proceeding.
Get a free desk feasibility — 7 working days
Send us 12 months of half-hourly meter data and a roof drawing (PDF or DWG). Within 7 working days we deliver: indicative system size from PVSyst modelling of your specific roof; financial DCF showing payback, IRR and NPV under three financing routes (outright purchase, asset finance, PPA); customer Scope 3 audit pack template for your supply chain context; grant funding eligibility assessment (IETF, UKSPF, Enterprise Zone ECA, Freeport ECA); DNO connection cost estimate from grid heatmap; structural pre-assessment from drawings; honest assessment of whether your site suits solar. No charge, no obligation. Call +44 7707 970 661 to discuss, or send your meter data to info@solarpanelsforwarehouses.co.uk — quote within 7 working days, guaranteed.