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Simple Carbon Calculator |
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This page contains a simple carbon calculator for use by UK organisations based upon the recommended conversion factors provide by Defra as part of its Environmental Reporting Guidelines. |
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Individuals wanting to calculate their carbon footprint are recommended to go to the Carbon Workout section of the NEF website.
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Directions: Type the energy value from your bill or records into the left column. Then click anywhere outside the cell you just filled. The answer will appear in the column to the right.
Which electricity factor should we use?
This table offers two factors for converting UK electricity to its carbon dioxide equivalent: one based on marginal emissions (which are usually those from high efficiency Combined Cycle Gas Turbines - CCGT) and one based on the average UK electricity mix. If you are using this table to estimate emissions in line with Climate Change Agreements (CCAs), then the marginal, lower figure (0.43) should be used. This figure may also be the more appropriate figure when estimating energy savings. If, on the other hand, you want to know your carbon footprint, then we would normally recommend using the higher figure (0.523) which is based on a 5 year rolling average UK electricity generation mix of coal, nuclear and gas turbines, as well as renewables. For other countries, the electricity component would need to be adjusted based upon primary fuel mix. Don't put your consumption in both the boxes, as it will otherwise be counted twice.
For electricity generated from renewable sources, zero carbon dioxide emissions may be used if the supply has been certified by OFGEM or generated onsite.
What do these figures mean?
Around half UK CO2 emissions come from industry and commerce, including the use of transport to deliver goods. This calculator should help smaller companies identify their carbon footprint, based on available records of energy used. Larger organisations, which have already taken steps to reduce energy use and their carbon footprint, are advised to find out more about the Energy Efficiency Accreditation Scheme, which uses a more sophisticated carbon calculation. Individuals are recommended to use the Carbon Workout instead, although the table above could be used to estimate emissions from your fuel bills.
Where do these figures come from?
All data in this table is based upon official UK data from the Department of Environment, Food and Rural Affairs, revised March 2001. Emissions for other fuels can be found on Defra's Environmental Reporting page. Figures have been updated to include the June 2007 data where applicable. This table only gives some of the main conversion factors, and CO2 equivalents are given on a Gross Calorific Value basis: Defra intends to move to a net CV basis in the near future which will slightly increase emission factors from natural gas and LPG.
The car mileage figure is based upon an average UK family car returning 29mpg. If your car fleet returns better figures on average, (or you driving a smaller car achieving (say) 40mpg, or regularly share a car) then you could adjust the mileage accordingly to estimate CO2 emissions.
Aeroplane emissions are very hard to estimate. The figure above is based upon short-haul (European) flights in economy class - add up to 50% for business class travel with lower seat densities. However there is some evidence that there is at least as much Global Warming effect again from other aircraft emissions in the upper atmosphere, such as ozone created from NOx or condensation trails, than solely from the CO2 emitted on the journey. Our personal Carbon Workout allows you to estimate emissions from specific journeys, using a database of over 500 airports served by UK flights.
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