What causes a kg of CO2 emissions?
Following 'how precious is a kWh' and 'how precious is a m3 gas', and using a sheet from Good Energy, we can estimate the amount of energy services that emits a kg of CO2 (specific for the UK system). A kg of CO2 emissions results from:
- operating an electric radio alarm clock for 23 days
- a 15 minute shower (or a 7 minute power shower)
- 20 minutes of gas cooking, or one hour of electric cooking
- 6 days of refrigeration (with a modern unit)
- 4 km travel by car, 16 km of travel by bus, train or tube
- Using a computer for 5 working days (9 hours)
- Operating a lift for 40 minutes
- Less than 1% of the distance Heathrow - Paris by air
- Transporting 3 bottles of wine from New Zealand
- Transporting 25% of a Red Snapper from the Indian Ocean
- 9 steak and ale pies made on-site using local produce
These figures are based on the UK electricity system (473 g CO2/kWh). For electricity applications in other countries, figures need to be adjusted depending on the relative carbon intensity of electricity generation. For example (source: Greenhouse Gas Protocol):
- Norway: 9 g CO2/kWh (i.e. multiple by 53)
- France: 82 g CO2/kWh
- China: 771
- India: 912 (i.e. divide by 1.9)
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Comments
Your figures for a car are very high, something like a 4 litre petrol Range Rover. A typcial small diesel will be about 9km for 1 kg of CO2 gross and will need to be factored for the number of passengers. Your figures for a bus or train are not gross figures but appear to be net figures for full occupancy. Should always compare like for like to avoid distortion or qualify your numbers.
Do not know how you get 1 hour of electric cooking to be the same as 20 minutes of gas cooking, as it takes about three units of heat to produce one unit of electricity in the UK?
This kind of impact is referred to as the ecological footprint. It’s how much damage you do and how many resources you use up during the course of a year. For most people, it’s an enormous amount, and a lot of us are trying to reduce our ecological footprints. However, this can be tricky, since heating and cooling our homes, transportation, and what we eat are the biggest contributors to this footprint. Those are difficult areas for many people to change significantly. However, if you think about it, changes can be made.
For instance, you could cut the CO2 emissions of your morning commute in half, just by taking the train. Plus, you’d get to skip dealing with traffic jams, stop lights, crowded intersections, and all the other hassles of commuting. Let someone else do the driving, and take the bus, or the train. People all over America are using public transportation more and more, with the number of trips taken rising by about six and a half percent. We drove about four and a half percent less in the last quarter of 2008.
Buses are far more efficient than driving as well. Did you know that mileage for a bus is around 146 miles per gallon per passenger? That’s more than almost all other methods of transportation. Around fifty cars could be eliminated from the already crowded highways in the morning and evening if their drivers simply chose to take a single bus. That makes it a good idea to investigate the cost and convenience of your city’s bus program.
Regards,
First of all, not that primary energy and carbon are increasingly decoupled in the electricity system. It is correct that electricity requires about 2-4 units of heat in thermal power stations. But close to half of Europe's electricity supply is low carbon (hydro, nuclear, new renewables). A comparison on the basis of primary energy or carbon may differ significantly, and increasingly so in the future.
Secondly, gas and electric cooking to not consume the same amounts of energy for the same cooking effect. In case of electricity, the efficiency in use can be much higher, requiring less kWh to cook the same meal as with gas.