How we calculate total emissions

• Energy used in our buildings is recorded as kWh.  This is converted into an equivalent CO2 emission using current government conversion factors (the UK figures are provided by DEFRA.  US, French and Brazilian data are converted using factors from Energy Agency Data Services 2006).  Where we do not have data from smaller buildings we have grossed up national totals based on the number of people in these non-metred sites.
  
  
• Road data is recorded as a mix of distance travelled (in some parts of the business) and fuel used (in others).  In general the data refers only to travel in company vehicles, but it does also include employees’ private mileage in these.  Fuel efficiency (miles per gallon or litres per kilometre) conversion factors are used to convert the whole into an equivalent consumption of diesel and petrol which are then converted to CO2 equivalents using the DEFRA factors.
  
  
• Air data is collected largely from ticket information, usually indicating the numbers and approximate ranges of flights (sectors flown).  These are converted using estimates into passenger-kilometres, which are then finally converted to CO2 using the UK DEFRA factors.

We have some limited data on rail and taxi travel, but this is incomplete and inconsistent so not included in our overall totals.  We estimate that it would be a very small figure compared to the other three sources.

The majority of data refers to the financial year ending 31st March 2008.  However in some cases (certain sites and – notably- all Serasa data) it covers a closely related 12-month period (often the calendar year 2007).  In some UK sites, partial year data has been grossed-up to represent a full twelve month total.

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Changes to carbon emissions calculations

When calculating our CO2 footprint we rely on agreed ‘emissions factors’ to convert the energy data (calculated from our fuel bills) into CO2 emissions.  The UK Government has recently revised its guidelines in this area. We have also – for the first time – applied different emissions factors to each of our four regions to accurately reflect variations in the way electricity is generated in each country.  Both of these changes have been made to all years back to 2005, to maintain comparability.  We treat renewable energy purchased via the UK national grid as having zero carbon emissions. There is currently a consultation process underway to propose a new treatment of such ‘green tariffs’ which may affect the carbon footprint we report in future years.

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