How did we calculate what percentage contribution rail transport makes to the average person’s carbon footprint?
According to Defra1 , the average person’s carbon footprint is 4.483 tonnes per year, 2.687 tonnes of which comes from home and appliances and 1.796 tonnes per year comes from transport. So we simply divided 1.796 tonnes by 4.483 tonnes and multiplied by 100 to give us a 40.06% contribution by transport.
How did we calculate how much CO2 you would save if you reduce your carbon footprint by 20%?
0.2 multiplied by 1.796 tonnes is 0.3592 tonnes or 359.2kg.
How did we work out that’s the same as the CO2 emitted by the electricity used to power a TV for 3 years?
The average daily usage of a TV is 0.57kW of electricity2. We multiplied this figure by 0.523, the conversion factor for electricity (Defra3),. This gives us a figure of 0.29811kgCO2, which is the amount of CO2 emitted by the electricity used to power one TV in a day. If you save 359kgCO2, then divided by 0.29811 gives us a figure of 1,204.92, which is the number of days it would take to use the same amount of electricity as would emit 359kg of CO2. 1,204.92/365 = 3.30 years.
We calculated the CO2 emissions per passenger for trains as follows:
We got the distance between the two stations from the National Rail Timetable. We then converted this distance to kilometres by multiplying it by 1.609344. We calculated the carbon emissions by multiplying the distance in kilometres by 0.0602, the conversion factor for rail (Defra3).
We calculated the CO2 emissions per passenger for cars as follows:
We got the distance between the two train stations by road from theaa.com. We then converted this distance to kilometers by multiplying it by 1.609344. We calculated the carbon emissions for the journey by multiplying the distance in kilometres by 0.2095, the conversion factor for an average petrol car (Defra3). We then divided this figure by 1.58, the average loading of a car (DfT4), to find the carbon emissions for this journey per passenger.
We calculated the CO2 emissions per passenger for domestic flights as follows:
We got the distance between the two train stations by air from transportdirect.com. We then converted this distance to kilometres by multiplying it by 1.609344. We calculated the carbon emissions for the journey by multiplying the distance in kilometres by 0.158, the conversion factor for a domestic flight (Defra3).
We calculated the carbon saving of taking the train instead of the car / plane by simply subtracting the rail carbon emissions from the car / plane carbon emissions.
We calculated the number of days it would take for a TV to use the same amount of electricity as would emit the same amount of CO2 as the journey’s carbon saving as follows:
The average daily usage of a TV is 0.57kW of electricity2. We multiplied this figure by 0.523, the conversion factor for electricity (Defra3),. This gives us a figure of 0.29811kgCO2, which is the amount of CO2 emitted by the electricity used to power one TV in a day. We then divided the amount of CO2 saved by taking the train by 0.29811.
We calculated the CO2 emissions over a year on a 25 mile journey as follows:
To find the CO2 emission of a 25 mile (40.23km) train journey, we multiplied the distance in kilometres by 0.0602, the conversion factor for rail (Defra3). This gave us 2.42 kgCO2. To find the CO2 emission of a 25 mile (40.23km) car journey, we multiplied the distance in kilometres by 0.2095, the conversion factor for an average petrol car (Defra3), then we divided this figure by 1.58, the average loading of a car (DfT4) to get 5.33 kgCO2, the CO2 emissions per passenger. Therefore, the CO2 saving on a 25 mile journey taking the train instead of driving is 5.33 minus 2.42 = 2.91 kgCO2. You need to get home again, so multiplied by 2 give us a saving of 5.83 kgCO2 for a return journey. If you do this once a month, over a year you would save 5.83 x 12 = 69.91 kgCO2.
How did we work out that’s the same as the CO2 emitted by the electricity used to power a TV for over 7 months?
The average daily usage of a TV is 0.57 kWh of electricity (Defra2). We multiplied this figure by 0.523, the conversion factor for electricity (Defra3),. This gives us a figure of 0.29811 kgCO2, which is the amount of CO2 emitted by the electricity used to power a TV in a day. If you save 69.91 kgCO2, then divided by 0.29811 gives us a figure of 234.49, which is the number of days a TV would take to use the same amount of electricity as would emit 69.91 kg of CO2. 234.49/(365/12) = 7.71 months.
We calculated the amount of CO2 produced traveling by train between Newcastle and Manchester as follows:
The distance between Newcastle and Manchester by train is 148.25 miles (238.59 kilometres). To find the CO2 emissions for this distance by train, we multiplied the distance in kilometres by 0.0602, the conversion factor for rail (Defra3). This gave us 14.36 kgCO2.
We calculated the amount of CO2 produced traveling by car between Newcastle and Manchester as follows:
The distance between Bedford and Gatwick by car is 136.40 miles (219.51 kilometres). To find the CO2 emissions for this distance by car, we multiplied the distance in kilometres by 0.2095, the conversion factor for an average petrol car (Defra3). We divided this figure by 1.58, the average loading of a car (DfT4). This gave us 29.11 kgCO2, which is the CO2 emissions per passenger
We calculated the amount of CO2 saved over a year as follows:
For a single journey, the carbon saving by train vs car is 29.11 minus 14.36 = 14.74 kgCO2. Therefore, for a return journey, the carbon saving is 14.74 x 2 = 29.49 kgCO2. If you have 4 weeks holiday and 8 public holidays, you work for approximately 46 weeks per year. So if you got the train instead of driving on this journey once a week for 46 weeks, you would save 29.49 x 46 = 1,356.42 kgCO2.
How did we work out that’s the same as the CO2 emitted by the electricity used to power a computer for 10 years?
The average daily usage of a computer is 0.69kWh of electricity (Defra2). To find out how much CO2 this emits, we multiplied 0.69 by 0.523, the conversion factor for electricity (Defra3). This gives us a figure of 0.36087kgCO2, which is the amount of CO2 emitted by the electricity used to power one computer in a day. If you save 1,356.42 kgCO2, then divided by 0.36087 gives us a figure of 3,758.75, which is the number of days it would take a computer to use the same amount of electricity as would emit 1,356.42 kg of CO2. 1,356.42/365 = 10.30 years.
We calculated the CO2 emissions over a year on a 40 mile journey as follows:
To find the CO2 emission of a 40 mile (64.37km) train journey, we multiplied the distance in kilometres by 0.0602, the conversion factor for rail (Defra3). This gave us 3.88 kgCO2. To find the CO2 emission of a 40 mile (64.37km) car journey, we multiplied the distance in kilometres by 0.2095, the conversion factor for an average petrol car (Defra3), then we divided this figure by 1.58, the average loading of a car (DfT4) to get the CO2 emissions per passenger. This gave us 8.54kgCO2. Therefore, the CO2 saving on a 40 mile journey taking the train instead of driving is 8.54 minus 3.88 = 4.66 kgCO2. You need to get home again, so multiplied by 2 give us a saving of 9.32 kgCO2 for a return journey. You make 5 journeys in a week, so the saving would be 9.32 x 5 = 46.60 kgCO2 per week. If you have 4 weeks holiday and 8 public holidays, you will do this approximately 46 weeks per year, so the saving over a year would be 46.60 x 46 = 2,143.75 kgCO2 per year.
How did we work out that’s the same as the CO2 emitted by the electricity used to power a fridge for 22 years?
The average daily usage of a fridge is 0.51kWh of electricity (Defra2). To find out how much CO2 this emits, we multiplied 0.51 by 0.523, the conversion factor for electricity (Defra3). This gives us a figure of 0.26673kgCO2, which is the amount of CO2 emitted by the electricity used to power one fridge in a day. If you save 2,143.75 kgCO2, then divided by 0.26673 gives us a figure of 8,037.17, which is the number of days it would take a fridge to use the same amount of electricity as would emit 2,143.75 kgCO2. 2,143.75 /365 = 22.02 years.
We calculated the amount of CO2 saved by traveling 200 miles by train compared to flying as follows:
To find the CO2 emission of a 200 mile (321.87km) train journey, we multiplied the distance in kilometres by 0.0602, the conversion factor for rail (Defra3). This gave us 19.38 kgCO2. To find the CO2 emission of a 200 mile (321.87km) plane journey, we multiplied the distance in kilometres by 109% to take into account circling (as recommended by Defra3), then multiplied this figure by 0.158, the conversion factor for a domestic flight (Defra3). This gave us 55.43kgCO2. Therefore, the CO2 saving on a 200 mile journey taking the train instead of flying is 55.43 minus 19.38 = 36.06 kgCO2.
How did we work out that’s the same as the CO2 emitted by the electricity used to power a lightbulb for 2 years?
The average daily usage of an 80W lightbulb is 0.08kWh of electricity (Defra2). To find out how much CO2 this emits, we multiplied 0.08 by 0.523, the conversion factor for electricity (Defra3). This gives us a figure of 0.04184 kgCO2, which is the amount of CO2 emitted by the electricity used to power one lightblub in a day. If you save 36.06 kgCO2, then divided by 0.04184 gives us a figure of 861.75, which is the number of days it would take a lightbulb to use the same amount of electricity as would emit 36.06 kgCO2. 861.75/365 = 2.36 years.
1 Defra 2007: Act On C02 Calculator Public Trial Version - Data, Methodology and Assumptions
2 Defra’s What If? Tool
3 Defra 2007: Guidelines to Defra’s GHG conversion factors for company reporting
4 DfT 2006, Transport Trends