Understanding Scope 2 and how solar reduces it
Under the GHG Protocol, Scope 2 covers indirect emissions from purchased electricity. UK grid electricity in 2026 carries a residual mix emission factor of approximately 0.185 kgCO2e/kWh (UK Government 2025 factors for market-based accounting) or approximately 0.207 kgCO2e/kWh for location-based accounting. A warehouse consuming 1,000,000 kWh/year from the grid has Scope 2 emissions of approximately 185-207 tonnes CO2e. A 1 MW solar install generating 900,000 kWh/year with 85% self-consumption (765,000 kWh consumed on site) directly displaces 141-158 tonnes CO2e — a 68-76% Scope 2 reduction for that site. The remaining grid supply (235,000 kWh) continues to carry the residual mix factor unless matched with REGOs.
REGOs and market-based Scope 2 reporting
Renewable Energy Guarantees of Origin (REGOs) are certificates issued to renewable generators by Ofgem — one REGO per MWh of renewable electricity generated. REGOs allow businesses to claim market-based Scope 2 accounting using a zero or near-zero emission factor for their purchased electricity, even when the physical electrons are from the grid mix. For self-generated solar electricity, REGOs are issued to the system owner and can be retained for own-use reporting or sold. GHG Protocol market-based method requires REGOs (or equivalent energy attribute certificates) to claim a zero emission factor — location-based method uses average grid intensity without REGOs. Most Tier 1 supply chain audit requirements specify market-based accounting with REGO evidence. We register every solar installation for REGO issuance and provide annual REGO certificates for GHG reporting.
Scope 3 Category 11: use of sold products and supplier audits
Scope 3 Category 11 (Use of Sold Products) is the primary mechanism by which retailers and manufacturers cascade decarbonisation requirements to logistics providers and warehouse operators. When Tesco, M&S, ASOS or JLR calculate their Scope 3 Category 11 emissions, they include the electricity used by their 3PL warehouse providers to store, pick and dispatch their products. Warehouse operators providing 3PL services to these retailers receive annual Scope 3 questionnaires requesting: (a) total site electricity consumption; (b) renewable electricity percentage; (c) REGO or equivalent certificate evidence. Operators without solar (or without green tariff REGOs) contribute high Scope 3 to their customers' reports — creating risk of losing contracts to lower-carbon competitors. Solar with REGOs is the cleanest, most audit-friendly answer.
SECR reporting and mandatory Scope 2 disclosure
Streamlined Energy and Carbon Reporting (SECR) requires UK companies above certain size thresholds (250+ employees, or turnover above £36m and balance sheet above £18m) to disclose energy use and greenhouse gas emissions in their annual Directors' Report. SECR mandates both location-based and market-based Scope 2 reporting from April 2019. Warehouse operators subject to SECR must separately disclose global energy use (in kWh) and GHG emissions (in tonnes CO2e) for each method. Solar PV reduces both location-based and market-based Scope 2 emissions. REGOs issued to the solar owner allow zero-emission market-based reporting for self-consumed electricity. For multi-site SECR-reporting businesses, portfolio solar programmes across the warehouse estate create the fastest path to demonstrable SECR progress.
Practical solar reporting setup: from installation to audit
Setting up correct solar reporting for customer audits requires: (1) Smart meter or data logger — half-hourly generation and consumption data essential for self-consumption calculation; (2) REGO registration — system owner registers with Ofgem via an accredited scheme, REGOs are issued quarterly; (3) Annual REGO statement — issued to system owner at year end, available as GHG audit evidence; (4) GHG Protocol worksheet — completed using REGO-verified renewable electricity and residual mix factor for remaining grid supply; (5) Customer audit submission — most retail and logistics customer audits accept the GHG Protocol worksheet + REGO certificate combination as sufficient evidence. We provide full REGO setup, annual certificate management, and a GHG reporting pack for every installation as standard.
Common questions
Do I need REGOs to claim zero Scope 2 for solar self-consumption?
Under the GHG Protocol market-based method, yes — REGOs are required to claim a zero emission factor for self-generated solar electricity. Location-based reporting uses average grid intensity regardless of REGOs. We register every installation for REGO issuance and provide annual certificates.
How much does warehouse solar reduce Scope 2 emissions?
A 1 MW solar install on a warehouse consuming 1,000,000 kWh/year with 85% self-consumption reduces Scope 2 by approximately 141-158 tonnes CO2e/year — a 68-76% Scope 2 reduction. With REGOs, all self-consumed solar is reported at zero market-based emission factor.
Will Tesco or ASOS accept solar REGO certificates as audit evidence?
Yes — most major UK retailers accept GHG Protocol market-based reporting with REGO certificates as sufficient evidence for Scope 3 supply chain audits. The combination of our GHG reporting pack and annual REGO statement has been accepted by Tesco, M&S, ASOS, JD Sports and Amazon in customer audits we have supported.
What is SECR and does it apply to my warehouse?
SECR (Streamlined Energy and Carbon Reporting) applies to large UK companies: 250+ employees, or turnover above £36m AND balance sheet above £18m. Qualifying companies must disclose energy use and GHG emissions (Scope 1 and 2, location- and market-based) in the annual Directors' Report. Solar PV reduces both reported figures and demonstrates climate action to investors and auditors.