DESNZ publishes a full set of conversion factors from 2012. For 2002 to 2011 it has republished electricity and heat only, so until today a gas bill or a business trip from 2008 had no factor in the app. We have now filled that gap from the guidelines Defra, and later Defra and DECC, published each year.

What is new

  • Fuels, vehicles and travel from 2002: gas, oil and other fuels, cars, lorries, flights, rail, freight and refrigerants. Motorbikes follow from 2007, and vans, buses, taxis and ferries from 2008. The 2007 edition has no lorry or freight figures.
  • Waste and water from 2009, and material use in 2011.
  • 7 editions, 4,056 factors. Coverage grows over time, from 120 factors a year in the 2001 edition to 1,129 in the 2011 edition.
  • An audit trail. Every figure is traced to an archived copy of the original file and the page or row it came from, with a record of anything left out and why.

Two limits are worth knowing. Editions before 2009 give kg CO2 only, not the other greenhouse gases, and the app labels them that way. And older editions cover fewer activities, so some combinations still have no factor.

Who it helps

Any business whose baseline or earlier figures date from before 2012. If you are restating a baseline after buying a business or fixing an error, each year should keep its own year's factors. Now an old year's records can be worked out with the factors published for that year, rather than a later set.

The year makes a difference. As an example, an office burning 30,000 kWh of gas in 2005 produced 5.70 tonnes CO2 at that year's factor of 0.19 kg per kWh, against 5.47 tonnes CO2e at the 2026 factor of 0.18231.

Jak jej používat

Add a past year's bills, mileage and travel with their real dates. The app picks the factor year from the dates, and each calculation line names the edition behind it, such as "Defra 2005 guidelines, kg CO2 only". Reports covering a year before 2012 include a method note saying so. For a Carbon Reduction Plan baseline before 2012 you still type in the Scope 1, 2 and 3 totals, which you can now work out in the app first.

The public factor pages show the older years too, marked with a footnote: see natural gas, petrol cars and short-haul flights, or browse every emission factor.

Jak pomáhá Carbon Recycling

The app now works out a past year from 2002 with that year's published factors and shows which source each line used, so an old baseline and this year's footprint can be compared honestly. Our earlier post on UK factors back to 2002 covers electricity, heat and spend multipliers. Once your figures for 2012 or later are ready, the free Report check recalculates their electricity and gas and lists anything a Carbon Reduction Plan or SECR report is missing: read how the Report check works.