‘kWh’ into ‘kg of carbon dioxide equivalent’- conversion table
Greenhouse gas conversion factors are used to calculate the amount of greenhouse gas emissions caused by energy use. They are measured in units of kg carbon dioxide equivalent**. In order to convert ‘energy consumed in kWh’ to ‘kg of carbon dioxide equivalent’, the energy use should be multiplied by a conversion factor.
Example
To convert from litres of petrol to kgCO2e emissions multiply by 2.331, so for example:
200 litres petrol = 200 x 2.331 = 466.2 kgCO2e
Note: Carbon emissions are usually quoted in kgCO2/kWh. If you wish to convert the carbon dioxide factors into carbon (ie kgC/kWh), multiply the figure by 12 and divide by 44.
Defra published updated conversion factors for 2011 (.xls), which can be found on their website. These 2011 conversion factors are summarised below:
| Conversion to CO2e (gross CV basis) |
| Energy source* | Units | Kg CO2e per unit |
| Grid electricity | kWh | 0.5246 |
| Natural gas | kWh | 0.1836 |
| LPG | kWh | 0.2147 |
| | litres | 1.4918 |
| Gas oil | kWh | 0.26744 |
| | litres | 3.0595 |
| Fuel oil | kWh | 0.2674 |
| | tonnes | 3228 |
| Burning oil | kWh | 0.2468 |
| | tonnes | 3165 |
| Diesel | kWh | 0.2517 |
| | litres | 2.6676 |
| Petrol | kWh | 0.2407 |
| | litres | 2.3117 |
| Industrial coal | kWh | 0.3325 |
| | tonnes | 2383 |
| Wood pellets | kWh | 0.039 |
| | tonnes | 183.9 |
Our publication Conversion factors - Energy and carbon conversions contains these factors along with a spreadsheet to enter your usage and calculate carbon emissions.
Notes:
*The conversion factors presented here are just a sample of those published by Defra. For a more comprehensive set of factors and full guidance notes for their use, see:
Defra - Measuring and reporting environmental impacts
Energy units into kWh-conversion table
The following table gives the number you need to multiply by to get from a variety of different units to kWh.
| | Unit | | Factor | | Unit |
Energy
| therm | x | 29.31 | = | kWh |
| Btu | x | 0.0002931 | = | kWh |
| MJ | x | 0.2778 | = | kWh |
| toe | x | 11,630 | = | kWh |
| kcal | x | 0.001163 | = | kWh |
Power
| hp | x | 0.7457 | = | kW |
| Btu/h | x | 0.0002931 | = | kW |
‘kWh/tonne’ and ‘kWh/litre’-conversion table
If you buy fuels by volume or weight, you need to know the calorific value of the fuel to find out the energy units. This should be specified by the fuel supplier, but where this data is not available the typical values given below can be used:
| | By weight | By volume |
| Solid fuels | | kWh/tonne | kWh/litre |
| Coal (weighted average) | 7,500 | - |
| Industrial wood | 3,806 | - |
| Short rotation coppice | 3,086 | - |
| Straw | 4,389 | - |
| Liquid fuels | | kWh/tonne | kWh/litre |
| Fuel oil | 12,028 | 11.85 |
| LPG | 13,667 | 7.08 |
| Gas/ diesel oil | 12,583 | 10.89 |
| Burning oil | 12,833 | 10.32 |
| Petrol | 12,806 | 9.42 |
| Gaseous fuels | | kWh/tonne | kWh/m3 |
| Natural gas | - | 11.13 |
Source: Department of Energy and Climate Change - Digest of UK Energy Statistics 2011
Greenhouse gas conversion
Some greenhouse gases have a greater impact on climate change than others. Therefore, different greenhouse gases will have different levels of CO2 equivalents (the amount of CO2 which would have to be released in order to have an equal impact on the atmosphere).
| GHG | Multiply by the following figure to
obtain the CO2e value: |
| CO2 | 1 |
| CH4 | 21 |
| N2O | 310 |
| SF6 | 23,900 |
| HFCs | 140 - 11,700 |
| PFCs | 6,500 - 9,200 |
(Data source: 2011 Guidelines to Defra/DECC's GHG Conversion Factors for Company Reporting)
**The energy conversion factors on this page are quoted as kilograms carbon dioxide equivalent (kgCO2e) per unit of fuel. The use of fuels leads to emissions of carbon dioxide (CO2) and small quantities of other greenhouse gases including methane (CH4) and nitrous oxide (N2O). For a given quantity of a gas, the equivalent quantity of CO2 that would be needed to give the same greenhouse gas effect can be calculated using its "Global Warming Potential". This is quoted in units of kilograms carbon dioxide equivalent (kgCO2e). For the 2010 conversion factors, the greenhouse gas conversion factor for a fuel comprises the effect of the CO2, CH4 and N2O combined (this is quoted as kgCO2e per unit of fuel consumed).