How we calculate total emmissions. Read more

Changes to carbon emissions calculations. Read more

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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Carbon Footprint

There are three main sources to our carbon footprint:

  • Emissions from the electricity and fuel we use in our buildings

  • Emissions from road travel

  • Emissions from air travel

 

Carbon Footprint Building energy use per $'000 for Serasa and UK, US and France for 2005-2008 Building energy use for Serasa, UK, US and France for 2005-2008 Total CO2 emmissions for transport and buildings for 2005-2008

The majority of data refers to the financial year ending 31 March 2008 but in some cases (including the Serasa data) it covers a closely related 12 months (often the calendar year 2007).For some UK sites near complete data has been grossed up to represent a full twelve month total.
 

This year we reduced our footprint by 6% even with the inclusion of Serasa for the first time.  The  building energy use (UK, France and the US) increased by 1% but this was due to us including many new, smaller sites for the first time to give a more complete and accurate picture of the total.

One contributing factor to the increase being so small is the increased amount of renewable electricity we buy.  Consistent with the current UK Government guidance, we have treated this as having zero carbon emissions.  Renewable electricity now represents 22% of all energy used in our offices in the UK, France, US and Serasa. 

In the US, Experian’s Allen, TX facility has been powered since June 2007 by 100% green energy generated by wind farms in the west Texas panhandle.  Seventeen percent of the power used in our buildings in Costa Mesa, CA comes from a renewable source.  We are investigating the cost and impact of extending similar arrangements to our McKinney, TX Data Center. In October 2007, the UK’s entire Nottingham estate switched to 100% green electricity from supplier EDF.

Reducing energy consumption has also been important to us and our data centres have led the way with numerous initiatives. Our UK and US data centres have introduced a programme of server virtualisation to significantly reduce energy demand. Cooling is also an issue.  As servers become more compact they create more heat. In the UK, a change to the layout and flooring in the data halls has improved airflow over the hardware reducing power consumption used for cooling. In Allen, TX we are replacing our building chillers and introducing more efficient chilled and condenser water pumping systems. We are also monitoring and measuring the power consumption of equipment to help inform future purchases and buying based on long term energy efficiency as well as price.

For the future, we are investigating the installation of our own wind generators in McKinney and Allen and looking at power management for workstations and thin client computing to save energy on our workplace technology.

Offices have cut energy use, too.  In the UK, we have used a voltage trimming system which could help us save 50 tonnes of C02  per year. Our offices in Schaumburg, IL have saved 5% on electricity by installing variable frequency drives (VFDs) for the large HVAC motors. 

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