Personal Carbon Footprint Monitoring

Transition Ashtead is running a personal carbon footprint monitoring scheme which TA members, colleagues and friends are invited to join.  One’s footprint is a measure of how much CO2 is emitted as a direct result of those activities that are both under one’s own direct control and that can be simply and adequately measured. These activities are home heating, home electricity use, eating and drinking, and road and air travel.

The idea is of course to help people to reduce their personal climate impact. Measuring the impact makes it much easier to focus one’s efforts on the most effective practicable steps to take.
If you want to find out more information and join the scheme, please email Tony Cooper
The scheme comes into effect on January 1st 2012.

Rules of Transition Ashtead (TA) Personal Carbon Footprint (PCF) Self-Monitoring Scheme

2011 DECEMBER 15

The rules of the Scheme are set out below. They are loosely based on Green Mole Forum scheme rules. 


1.  All TA members may join.  Membership is voluntary, and members may leave the scheme at any time.


2. The scheme includes carbon dioxide (CO2) emissions from the following sources:

  • Home heating
  • Home electricity
  • Transport by own car or motorbike
    • Air travel
    • Food.

The scheme does not include public transport or use of other products and services as there is no easy way to calculate these contributions.

3. The scheme is based on emissions per adult person, not households.

PCF Calculations

4.  Members will supply the following information to enable their CO2 emissions to be calculated.

  • Number of adults in household.  Use fractions for part occupation eg if an adult is present 6 months of the year, count as 0.5 adults.  Children under 18 count as one third of an adult.
  • Gas and electricity meter readings at 1 Jan 2012 and 2013.
  • No reductions or adjustments are allowed for a renewable or green electricity tariff.  See note 1.
  • Domestic generation of electricity is offset against consumption.
    • Air travel.  To find out emissions from air travel, members need to use the air travel calculator on the Climate Care web site (, entering the flight start and end locations.  Business flights are excluded, in line with other business travel..
    • Personal car or motorbike mileage, fuel (diesel or petrol), and average mpg.  This requires members to record the odometer readings at 1 Jan 2012 and 2013, and to calculate their average mpg by recording the quantities of fuel and miles travelled over a few months.
      Alternatively, and more accurately, members may record all their fuel purchases during the year. A year-end adjustment is in theory appropriate but we can manage fine without it.
    • If a car is shared, members need to either record the mileage when they are driving, or simply estimate the fraction of the total miles that are attributable to them (see note 2).  Travel to and from normal place of work is included, but other business mileage, including self-employed person’s business mileage, is excluded.  Alternatively members may record the volumes of fuel bought over the year and allocate it to business and personal use.
    • Ideally all taxi and car-hire use for non-business purposes should be recorded too. You should record the mileage of each journey (The AA website is useful for saying how far it is from A to B), and, if shared-use, the number of people in the vehicle). Great accuracy isn’t necessary, estimating the distance to, say, the nearest 50 miles is adequate. For hired cars you can instead record the fuel volume bought and that gives a better estimate.


5. CO2 emissions are calculated using the following factors as published by the Department of Energy and Climate Change


2010 2011 2012
Electricity kg per kWh .473 .471 .451
Gas kg per kWh .18
Petrol kg per litre 2.23 2.21 2.19
Diesel kg per litre 2.53 2.52 2.51


6.  The embodied carbon in food is estimated using the following values.

(See Note 3)

Diet CO2tonnes per person per year
Average UK 2.0
Low meat (see note 4) 1.7
Lacto -vegetarian 1.4
Vegan 1.0

Calculating the Value of Personal Carbon Emissions

9. At the start of 2012, members will report their meter readings and if appropriate odometer readings to the PCF scheme administrator, currently Tony Cooper.

10. At the end of each year, the members will report their consumption figures to the PCF administrator who will calculate and record their CO2 emissions from the data provided.  A small prize will be awarded for the member with the lowest emissions, and, starting in year 2, another for the biggest reduction in emissions.

11. If people want, to maintain interest during the year, they may report quarterly figures. I find that helpful, but it isn’t essential.


1.   No reductions are allowed because unfortunately there is no way of clearly demonstrating the reduction is emissions (if any) that arises from switching to a green tariff.  Despite this we still want to encourage people to select a good green tariff.  The following are recommended by most surveys: Good Energy, Green Energy and Ecotricity. This position should be kept under review if possible.

2.   For example suppose a shared car does 10000 miles per year.  A drives 1000 miles alone, B drives 4000 miles alone, 5000 miles is shared.  Miles attributable to A is 1000 + 5000/2 = 3500.  Miles attributable to B is 4000 + 5000/2 = 6500.

3.   These figures are a rough approximation, provided by the Green Mole Forum. It’s hard to find a reliable and comprehensive source for food emissions, perhaps because it’s a complex issue. There are many plausible sources with partial data and further references. I hope to investigate further but this will take time. Clearly if one changes one’s overall diet category partway through the year, the final figure is an appropriate average.

4.   A low meat diet means at least three meatless days per week.  Fish counts as meat.

Tony Cooper 16th December 2011