Methodology

How Carbon Recycling turns your activity data into emissions, and the choices we make on your behalf.

Standards

Calculations follow the GHG Protocol Corporate Accounting and Reporting Standard and its Scope 3 standard, and the HM Government Environmental Reporting Guidelines used for SECR. Results are in tonnes of carbon dioxide equivalent (tCO₂e), covering the seven Kyoto Protocol gases.

Conversion factors

We use the UK Government GHG Conversion Factors for Company Reporting published by the Department for Energy Security and Net Zero, loaded from the official flat files for 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025, 2026. We keep the total kg CO₂e factor for each row. All the entries in one of your reporting years use the same set: the one for the calendar year in which most of that reporting year falls (DESNZ calls this the “majority” approach), so an April to March year uses the set for the year it starts in and a July to June year uses the set for the year it ends in. Years before 2002 use the 2002 set, and years after the latest published set use the latest.

DESNZ only gave its factors stable IDs from 2023. For the 2002 to 2022 sets we match each row to the 2023 row with the same description and unit, so the same activity finds the right factor in every year. 2014 onwards come from DESNZ's flat files; before 2014 there is no flat file, so we read the published full-set workbooks table by table. For 2002 to 2011 DESNZ republished only its electricity and heat factors, so those years cover electricity (UK and overseas), heat and steam, grid losses and their well-to-tank figures, and nothing else. Where an older set simply doesn't include a factor (propane and butane before 2021, homeworking before 2022, hotel stays before 2017, electric cars and vans before 2017) we say so rather than borrowing a later year's value. Older sets don't publish well-to-tank figures for every fuel; those optional lines are left out for that year.

Every calculated line stores the factor's DESNZ ID, year and value, and is shown next to the figure in the app and in exports.

Scope 2 electricity

Location-based: the DESNZ UK grid electricity factor.
Market-based: zero for tariffs backed by REGOs, the supplier's fuel-mix factor when you enter one, and otherwise the UK residual fuel mix from the DESNZ fuel mix disclosure data table (Open Government Licence v3.0), as the GHG Protocol Scope 2 Guidance asks. The residual mix is what is left of UK electricity once every renewable and supplier-specific claim has been taken out, so it is higher than the grid average. We hold it from 2025; for earlier years the market-based figure uses the grid factor.
Transmission and distribution losses are reported separately in Scope 3 category 3.

Sites outside the UK

A site's country sets its electricity factor. US sites use the eGRID total output rate for their power region, from the GHG Emission Factors Hub (US EPA, and Cornerstone from 2026). Australia, Canada, China, France, Germany, New Zealand and Singapore use their government's own published grid factor (DCCEEW's National Greenhouse Accounts Factors; Environment and Climate Change Canada's National Inventory Report; the Ministry of Ecology and Environment's announcements; ADEME's Base Carbone; the Umweltbundesamt's electricity mix figures; New Zealand's Ministry for the Environment; the Energy Market Authority on data.gov.sg), unless Ember has a figure more than a year newer. Every other country uses its grid average from Ember's yearly electricity data (CC BY 4.0).
We use the latest data year up to your reporting year. No UK grid losses or well-to-tank are added. Other activity at these sites uses the DESNZ factors.
SECR reports for unquoted companies cover UK energy, so overseas electricity is listed separately. Full details are in section 14 of our terms.

Scope 3

Each entry is assigned to a GHG Protocol Scope 3 category. Well-to-tank emissions for the fuel and electricity you buy go to category 3. For travel and freight, where someone else buys the fuel, the well-to-tank share goes in the same category as the journey (business travel, commuting or transport), as the GHG Protocol sets out. Flights include radiative forcing by default, as DESNZ recommends. Supplier-reported figures are recorded as supplied, after you accept them.

The PPN 006 Carbon Reduction Plan reports the five categories the standard requires: upstream transport (4), waste (5), business travel (6), employee commuting (7) and downstream transport (9).

Energy for SECR

Energy in kWh is taken from bills where you enter kWh. For fuels entered by volume or mass, and for vehicles entered by distance, we derive kWh from the ratio of DESNZ factors for the same fuel, on a gross calorific value basis.

Periods

Reporting years follow your financial year. An entry covering part of a reporting year, such as a bill that crosses the year-end, is apportioned by the number of days that fall inside it.

Spend-based estimates

For purchases you have no better data for, you can enter what you spent, net of VAT, and we multiply it by the government's spend-based emissions multipliers (Defra and the University of Leeds, kg CO₂e per £, by Standard Industrial Classification). We use the multiplier for the year the money was spent, or the latest published year (currently 2023) for later spend. Prices have risen since then, so recent estimates lean slightly high.

Spend estimates are averages for a whole industry, so they are the least precise method. Defra itself advises activity data where you have it. We leave energy and fuel out of spend because you record those in kWh and litres, and we don't offer codes whose multipliers don't suit business purchases, such as wholesale trade. Supplier-reported figures, where you can get them, replace the estimate.

What we don't do

We don't net off carbon credits or offsets against your emissions.
Our figures aren't independently verified. PPN 006 doesn't require verification, but some buyers ask for it.