FOI request detail

Average carbon dioxide emissions in grams per kilometer of London bus fleet

Request ID: FOI-3213-1920
Date published: 17 February 2020

You asked

Could you please let me know the average carbon dioxide emissions in grams per kilometer (or equivalent calculations eg. kg/m) of new electric single deck and double decker buses? As i know some electric buses have diesel engines for air conditioning etc. There is very little information available on their carbon emissions. I would also like to know whether this answer is generally the same across all buses in the fleet, or if those with faulty hybrid engines which essentially only run on diesel have a different level of CO2 emissions.

We answered

TfL Ref: FOI-3213-1920

Thank you for your request received by Transport for London (TfL) on 23 January 2020 asking for information about buses.

Your request has been considered in accordance with the requirements of the Environmental Information Regulations and our Information Access Policy. You asked:

Average carbon dioxide emissions in grams per kilometre of London bus fleet

Could you please let me know the average carbon dioxide emissions in grams per kilometre (or equivalent calculations eg. kg/m) of new electric single deck and double decker buses? As I know some electric buses have diesel engines for air conditioning etc. There is very little information available on their carbon emissions. I would also like to know whether this answer is generally the same across all buses in the fleet, or if those with faulty hybrid engines which essentially only run on diesel have a different level of CO2 emissions.

The newest types of electric buses entering the London fleet do not have separately-powered heaters and emit no tailpipe emissions in London. While there are some earlier types of battery-powered buses which were supplemented with diesel heaters, we believe CO2 from these ancillary systems is negligible in relation to their power requirements. We have not conducted measurements.

The CO2 figures in the form we hold them for the types of buses you are interested in are listed below. We calculate this in two ways to give the CO2 produced from production to final use (Well to Wheel), the CO2 produced from production to filling up the vehicle (Well to Tank) and the CO2 emitted from the vehicle tailpipe by kilometre under test conditions with the bus operating as if it was operating on a standard London route (Tank to Wheel).

These are:-

Well to Wheel

•           Single-deck pure-electric (Well to Wheel: 168 gCO2e /km, Well to Tank: 168 gCO2e/km, Tailpipe: 0 gCO2/km)

•           Double-deck pure-electric (Well to Wheel: 213 gCO2e /km, Well to Tank: 213 gCO2e/km, Tailpipe: 0 gCO2/km)

•           The average Euro VI diesel-hybrid electric double deck (Well to Wheel: 1162 gCO2e /km, Well to Tank: 226 gCO2e/km, Tailpipe: 936 gCO2/km)

•           The average Euro VI diesel single deck (Well to Wheel 1117 gCO2e/km, Well to Tank 217 gCO2e/km, Tailpipe 900 gCO2/km)

For info, the ‘e’ means equivalent Green House Gas (GHG) and is what is listed as being Well To Tank and Well To Wheel. It is used to show pre-combustion CO2 or total CO2 when considering pre and post combustion CO2.

Please see the attached information sheet for details of your right to appeal.

Yours sincerely,

Melissa Nichols

FOI Case Officer

General Counsel

Transport for London

Back to top

Want to make a request?

We'll email you the response within 20 working days.


We'll publish the response online without disclosing any personal information.