Calculate your carbon footprint – 2021 carbon conversion factors released

Businesses, News, Schools, Third Sector – Wednesday, June 2nd, 2021

Carbon conversion factors for 2021 have been released by the Department for Business, Energy & Industrial Strategy (BEIS). Find the highlights below. The methodology for determining carbon dioxide equivalents (CO2e) remains the same year on year except where changes are outlined.


As the main UK electricity grid continues to decarbonise with the increase in use of renewable sources, the carbon factor has decreased again this year by 8.93%.

Year on year percentage change in carbon conversion factor (Kg Co2e)

  • 2011  – 0.45205
  • 2012  – 0.46002 (2% increase)
  • 2013 –  0.44548 (3% decrease)
  • 2014 –  0.49426 (11% increase)
  • 2015 –  0.46219 (6.5% decrease)
  • 2016 – 0.41205 (10.84% decrease)
  • 2017 – 0.35156 (14.68% decrease)
  • 2018 – 0.28307 (19.48% decrease)
  • 2019 – 0.2556 (9.70% decrease)
  • 2020 – 0.23314 (8.79% decrease)
  • 2021 – 0.21233 (8.93% decrease)


Main changes and additions

Water supply and treatment

Conversion factors for 2021 have been based on 2020 data from UK water companies Carbon Accounting Workbooks, previously values came from the publication of the UK industry from 2012 that have been discontinued. This has resulted in significant carbon factor decreases of 56.69% for water supply and a 61.58% decrease for water treatment from the previous year.


Amendments to the methodology for the calculation of car emissions have been made for 2021 factors.

Material use

Glass factors have been revised to an up-to-date peer reviewed source. Factors for board have also been revised to include electricity and chemicals used during the board production and recycling process. Electrical good factors have also been revised using a new data source, there is a new category for IT goods and factors for batteries have been recalculated and disaggregated.

Waste disposal

Large changes to waste disposal to landfill factors for batteries which have been brought into line with electrical goods and other non-biodegradable items. Factors revised for compost and anaerobic digestion (AD) now cover the collection of material from the point where organic waste is generated and transport to the composting or AD facility, on site vehicle emissions have been removed as out of scope. This has seen a 12.28%decrease in carbon factor from the previous year for commercial and industrial refuse to AD for example.

Natural Gas and CNG – Well to Tank (WTT)

The methodology for calculating these factors has been improved to utilise updated data on leakage and energy use in transmission and distribution.

UK Electricity – Well to Tank (WTT)

The methodology has been improved to more appropriately account for indirect emissions from thermal renewables and other thermal energy sources.

Find more detail on methodology and the factors on the BEIS website.

If you are an organisation in or outside of Camden and would like assistance with your calculating your carbon footprint get in touch:

Reporting your organisation’s environmental performance can lower costs, improve understanding of exposure to climate change risks and demonstrates leadership and green credentials in the marketplace. The CCCA operate a FREE Carbon Certification scheme for organisations who report their annual energy data to us, for more information on the scheme go to our webpages