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Allows users to create and update their carbon footprint as a carbon account. By entering utility meter readings, gasoline/petrol consumption, daily commutes and plane trips etc., drupal registered users can build a picture of their CO2 emissions. Measuring one's own footprint is a big shock and awakening for many people - it is not just the [insert your country] government that's at fault.

To get going a user creates a carbon account. Then adds carbon stamps such as trips, meter readings etc as they occur throughout the year.

Users can display each year of their carbon account as a pie chart. Users can compare their account with other users on a bar chart which looks something like this.

The sources of carbon emissions are all configurable. The more obscure sources used in the resurgence calculator such as wood, butane etc, are also included. Users can also view footprints submitted by others. The software has been inspired and driven by the activities of the UK based carbon rationing action groups.

Note that unregistered users are unable to calculate their footprint. This and other matters are being discussed on this drupal forum thread.

In 2006, Juerg set up a google email list called carbon footprint calculators for general discussion about this and other carbon footprint calculators but that is pretty idle now.

For background information, another useful personal carbon accounting site in the UK is the RSA Carbon Limited site. It is based on .NET technology and a proprietary CMS. They have several thousand registered users.

Overview of Functionality available to the user

1. A registered user can create one or more named carbon accounts for him/herself or anybody else. By default the name of the account defaults to the name of the drupal user.

2. The same registered user can then add various kinds of carbon related activity such as meter readings, trips by car, trips by air etc, in fact any source of emission that has been configured by the admin or another person configured with the appropriate role.

3. When the account is being viewed, each carbon emission is listed, along with the date, amount etc.

Functionality available to users granted 'administer carbon nodes'

5. The administrator is able to add, edit and delete new sources of emissions. Each source of emission has a class that defines how the CO2 is calculated. The initial two classes are:

a) 'simple' - This class will simply take the number entered by the user and multiply it by an editable conversion factor.

b) 'climatecare' - This class implements the climate care flying algorithm which takes into the fuel required for take off and landing.

6. The administrator is able to view all accounts, and all the accounts in a given group (if user has specified on). Each individual account occupies one row on the page and the total of the carbon emissions and credits in Kg is displayed.

7. Like the user, the administrator is able to add carbon debits to any one carbon account.


The drupal carbon module defines three types of drupal node.

carbon account node

The carbon_account drupal node is loaded and saved from the carbon_account table by drupal's core routines. It contains the name of the footprint (not necessarily the same as the drupal account name) and preferences but no data related to energy or CO2.

carbon stamp node

Each carbon debit/credit is represented by carbon_stamp, another drupal content type and is saved in a row in the carbon_stamp table.

Each carbon_stamp is attached to one or more carbon_account. The joins between the carbon_stamp and carbon_account tables are held in the table carbon_stamp_account.

Users can share their carbon account with their friends. Their friends' uids are held in the table carbon_account_share.

carbon source node

Every type of source of emissions is represented by a drupal node. The drupal node is loaded and saved from the carbon_source table by drupal's core routines. Conversion factors, descriptions and units for each type of emission e.g. 'small car', 'miles' are held in that node.

Users with appropriate access are able to create,edit and delete new sources.

Each type of emission is associated with a named class e.g. simple or climatecare. This class is responsible for implementing methods that, for example, convert miles to CO2 emissions.

Each type of emission will be given some kind of unique short code like 'elec-kwh' by the person creating the source.

Each type of emission can be given a different model name such as 'CRAG' or 'carbon coach'. This means that curious individuals can create two carbon footprints using different models but use the same underlying data as long as both models use the same codes for the different sources. The user can change the preferred model on any carbon footprint at any time.

Latest Status: May 7th 2009

The drupal 6 version is stable and finished.

Further enhancements should include:

  • Better charting options
  • Integration with amee's carbon source database

Project Information

  • Maintenance status: Unknown
  • Development status: Unknown
  • Module categories: Content
  • Reported installs: 2 sites currently report using this module. View usage statistics.
  • Downloads: 8,590
  • Last modified: 2 December 2014
  • shield alertThis project is not covered by the security advisory policy.
    Use at your own risk! It may have publicly disclosed vulnerabilities.