Question: which has a greater embodied energy: a cup of tea/coffee or a can of Coke (or Pepsi, or other caffeinated soft drink) -- or maybe some other stimulating drink? I have made some estimates of my own, but there are some areas I haven't been able to figure out e.g. transportation, and I am looking for someone who may be better informed.
Factors
Cup of tea/coffee:
- Production of packaging
- Transportation from country of origin
- Heating water
Can of Coke:
- Production of packaging
- Transportation of raw ingredients
- Manufacture
- Transportation of product from the factory
My estimates:
Boiling one cup of tea: 0.11 kWh
500 g water (minimum amount for typical kettles)
Q = mcΔT
Q = Heating required
m = Mass of water = 0.5 kg
c = Specific heat capacity of water = 4.18 kJ/kgK [1]
ΔT = 85 Kelvin
Q = 178 kJ = 49.4 Wh
Efficiency of electrical power grid (e.g. in the US) [2]:
Generation: 40%
Transmission: 94%
Net effy = 38%
So total energy cost of a cuppa I'd reckon is 413 kJ = 0.110 kWh
Aluminum can production: 0.28 kWh
14.9 g : Mass of an empty can [3]
183e9 kWh : US total Aluminium industry energy consumption (2003) [4]
9.6e6 tonnes : US Aluminium industry raw materials used (2003) [4]
This gives 19.1 kWh/kg, or 0.28 kWh/can
Manufacture: ?
Not sure about energy required in manufacturing coke or blending tea.
Transportation: ?
Suspect transportation is fairly negligible in both cases as neither are perishable so probably transported by sea and road, which is relatively efficient.
References
- “Water - Thermophysical Properties.” [Online]. Available: https://www.engineeringtoolbox.com/water-thermal-properties-d_162.html. [Accessed: 23-Jan-2018].
- “Energy Efficiency in the Power Grid - NEMA,” mafiadoc.com. [Online]. Available: https://mafiadoc.com/energy-efficiency-in-the-power-grid-nema_59842ba91723ddcf69a39c32.html. [Accessed: 23-Jan-2018].
- “How much does an empty soda can weigh?,” Reference. [Online]. Available: https://www.reference.com/food/much-empty-soda-can-weigh-e7e0417d7a8ec29. [Accessed: 23-Jan-2018].
- E. Efficiency, “US Energy Requirements for Aluminum Production,” 2007. Available: https://www.energy.gov/sites/prod/files/2013/11/f4/al_theoretical.pdf