Scope 1: Direct emissions data
For Scope 1, you need consumption data for all fuels burned on-site or in owned vehicles. This means natural gas bills (in kWh or cubic metres), diesel and petrol purchase records for fleet vehicles (in litres), and any other fuel usage such as LPG, heating oil, or biomass. If you operate refrigeration or air conditioning systems, you'll also need records of refrigerant top-ups including the type and quantity of gas used. For most organisations, this data already exists in facilities management or fleet management systems.
Scope 2: Electricity and heat
Scope 2 covers purchased electricity, steam, heating, and cooling. You need electricity bills for every site showing kWh consumption. If you purchase renewable electricity through a REGO-backed tariff, keep the contract documentation for market-based reporting. For sites with half-hourly metering, you can get highly granular data directly from your energy supplier. If you're in shared tenancies where the landlord pays the electricity bill, request an apportionment or sub-meter data.
Scope 3: Value chain emissions
Scope 3 is where data collection gets challenging. For a spend-based approach, you need your procurement ledger — a list of all suppliers with the amounts spent, ideally categorised by product or service type. For activity-based calculations, you need physical quantity data: kg of materials purchased, km of freight, number of flights booked, km of employee commuting. Business travel data usually comes from your travel management company or expense system. Waste data comes from your waste contractor, showing tonnes by disposal method.
Practical tips for data collection
Don't wait for perfect data. Start with what you have and improve iteratively. Request data for your most recent complete financial year. Create a shared folder or form for site managers to upload utility bills. Set a deadline 8 weeks before your reporting date. Flag any data gaps early — it's better to estimate with documented assumptions than to leave categories blank. A good carbon accounting platform should accept your data in whatever format it exists, rather than forcing you into rigid templates.