Owned emissions
Our owned greenhouse gas (GHG) emissions are broken down by source to help us better understand our carbon footprint. 
Our owned emissions were 551,830 tonnes carbon dioxide equivalent in 2008/09, an increase from 401,512 in 2007/08 mainly due to changes in standard accounting rules as set by Defra .
- Electricity consumption emissions relate to our use of electricity from the national grid and emissions we are required to account from our renewable energy generation where we have sold the renewable obligation certificate. They increased from 281,909 tonnes carbon dioxide equivalent (tCO2e) in 2007/08 to 423,650 tCO2e in 2008/09.
- Process emissions are emissions of methane and nitrous oxide that occur as a result of our water and wastewater operations, such as thickening of sludge and incineration. They increased from 77,347tCO2e in 2007/08 to 97,009tCO2e in 2008/09.
- Other fuel use includes fuel oil, diesel and gas used in heating and back-up generators. This decreased from 19,667tCO2e in 2007/08 to 5,743tCO2e in 2008/09, due to our sludge incinerator being out of commission for some time during the year.
- Transport fuels include our fleet fuel purchase and our business mileage. This increased from 22,177tCO2e in 2007/08 to 25,139 tCO2e in 2008/09.
- Rail and air travel contribute 0.05% of our owned emissions and therefore are not visible on the chart.
Carbon intensity of our operations
Carbon intensity is a useful comparison measure used by the water industry and also our economic regulator. This is calculated for wastewater by taking our total operational emissions associated with wastewater and sludge treatment and dividing this by the total volume of wastewater treated. The same method is repeated for our water operations.
Our emissions intensity figures for 2008/2009 are:
- 881kg CO2e per million litres of wastewater treated
- 226kg CO2e per million litres of water treated
Our wastewater carbon intensity figure has increased by 71kg on last year’s data and our water figure has increased by 61kg even though our electricity consumption has gone down compared to last year, due to reporting factors discussed here.
The measurement of our carbon footprint is extremely important for us to be able to monitor and reduce our carbon emissions. This is an integral part of informing our carbon strategy .