Starting a carbon inventory can feel overwhelming, but the GHG Protocol Corporate Standard breaks the task down into three manageable “scopes,” each with its own typical data owners inside a business. This guide focuses purely on where to find the data you need for a first-pass inventory, using practical starting points, plus the data quality hierarchy the Protocol expects you to work towards over time.
Scope 1: Direct Emissions
Scope 1 covers emissions from sources your organisation owns or controls directly, such as gas combustion, generators, and refrigerant leaks. The data rarely sits in one place, so you’ll need to approach several internal teams:
- Gas invoices – held by Finance (accounts payable) or Facilities/Estates management, showing kWh or therms consumed per site per billing period.
- Generator fuel consumption – typically tracked by the building maintenance engineer or landlord via fuel delivery receipts, tank dip records, or generator run-hour logs.
- Refrigerant top-ups and leakage – recorded in F-Gas logs kept by the landlord, building services contractor, or air conditioning maintenance provider, since these are legally required refrigerant handling records in the UK.
Scope 2: Purchased Electricity (and Heat/Steam/Cooling)
Scope 2 covers emissions from purchased electricity, heat, steam, or cooling consumed but not generated by your organisation. The core source is:
- Electricity bills – from Finance (accounts payable) or Facilities, showing total kWh purchased per site per period; this is the most precise activity data available for Scope 2.
You’ll apply either a location-based factor (grid average, e.g. UK Defra conversion factors) or a market-based factor (supplier-specific, e.g. a green tariff), so check with Facilities or your energy broker whether you hold REGO certificates or supplier-specific tariffs.
Scope 3: Value Chain Emissions
Scope 3 is the largest and most complex scope, spanning 15 categories across your upstream and downstream value chain. For a first inventory, focus on gathering primary internal data before considering supplier engagement:
- Purchased goods and services – spend by supplier/category or quantities purchased, from Finance procurement/AP records.
- Business travel – distance by mode (air, rail, car) or travel spend, from Finance expense systems or your travel management company.
- Fuel and energy-related activities – fuel/electricity volumes already captured in Scope 1/2, cross-referenced from your own inventory.
- Waste generated in operations – waste tonnage by type and disposal route, from Facilities, the cleaning company, or IT (for WEEE/electronic waste).
- Water – consumption in cubic metres, from Finance water bills or Facilities.
- Employee commuting – commuting survey data or estimated distances, from HR or an employee travel survey.
The GHG Protocol’s Technical Guidance confirms utility bills, purchase records, meter readings, and internal IT systems are all valid activity data sources, and that spend-based data is an acceptable starting method when quantity data isn’t yet available.
Working With What You Have
Prioritise primary data (your own bills, invoices, meter readings) over secondary data (industry averages), but use spend-based or secondary data to fill gaps in your first inventory rather than delaying the whole exercise. As your inventory matures, progressively replace spend-based estimates with supplier-specific or quantity-based data for greater accuracy.
A Simple First Data-Gathering Checklist
- Request 12 months of gas and electricity invoices from Finance or Facilities, by site if possible.
- Ask the landlord or maintenance engineer for generator fuel logs and refrigerant service/F-Gas records.
- Pull a 12-month procurement/AP spend report from Finance, categorised by supplier type.
- Extract business travel bookings or expense claims from Finance or your travel management company.
- Request water bills from Finance or Facilities.
- Ask Facilities, your cleaning contractor, and IT (for WEEE/electronics) for waste transfer notes or waste contractor reports.
Once you have this baseline data, apply UK Government (Defra) conversion factors to calculate first-cut emissions figures across all three scopes, then refine with more granular, supplier-specific data over subsequent reporting cycles.
Sources
- GHG Protocol – Category 1: Purchased Goods and Services: https://ghgprotocol.org/sites/default/files/2022-12/Chapter1.pdf
- GHG Protocol – Guidance for Calculating Scope 3 Emissions: https://ghgprotocol.org/sites/default/files/ghgp/standards_supporting/GHG%20Protocol%20Guidance%20for%20Calculating%20Scope%203%20Emissions.pdf
- GHG Protocol – Corporate Value Chain (Scope 3) Accounting and Reporting Standard: https://ghgprotocol.org/sites/default/files/standards/Corporate-Value-Chain-Accounting-Reporing-Standard_041613_2.pdf
- GHG Protocol – Scope 3 Accounting and Reporting Standard (road-test draft): https://ghgprotocol.org/sites/default/files/ghgp/ghg-protocol-scope-3-standard-draft-for-road-testing-january-20101.pdf
- GHG Protocol – Scope 3 Frequently Asked Questions: https://ghgprotocol.org/sites/default/files/2022-12/Scope%203%20Detailed%20FAQ.pdf
- GHG Protocol – Technical Guidance for Calculating Scope 3 Emissions: https://ghgprotocol.org/sites/default/files/standards/Scope3_Calculation_Guidance_0.pdf
- GHG Protocol – Technical Guidance (mirror): https://ghgprotocol.org/sites/default/files/ghgp/standards/Scope3_Calculation_Guidance_0.pdf
- GHG Protocol – Scope 3 Calculation Guidance: https://ghgprotocol.org/scope-3-calculation-guidance-2
- GHG Protocol – Scope 1 & 2 GHG Inventory Guidance: https://ghgprotocol.org/sites/default/files/Guidance_Handbook_2019_FINAL.pdf
- GHG Protocol – Corporate Accounting and Reporting Standard (revised): https://ghgprotocol.org/sites/default/files/standards/ghg-protocol-revised.pdf
- KPMG – Handbook: GHG Emissions Reporting: https://kpmg.com/kpmg-us/content/dam/kpmg/frv/pdf/2024/handbook-ghg-emissions-reporting.pdf
- GHG Protocol – Scope 3 Frequently Asked Questions (2024): https://ghgprotocol.org/scope-3-frequently-asked-questions-0
- Gerresheimer – Scope 3 Methodology: https://www.gerresheimer.com/fileadmin/user_upload/Gerresheimer_Scope_3_Methodology_Documentation.pdf
- KPMG – Handbook: GHG Emissions Reporting (Dec 2024): https://kpmg.com/kpmg-us/content/dam/kpmg/frv/pdf/2024/handbook-ghg-emissions-reporting-dec-2024.pdf
- GHG Protocol – Corporate Value Chain (Scope 3) Standard overview: https://ghgprotocol.org/corporate-value-chain-scope-3-standard