Reckonings & Reminiscences

While watching news about Copenhagen Climate Conference, my father quipped “if all cities especially in America and Europe sleep by 10 then the energy saved is enough to achieve those targets.” Though exaggerated, there must be some savings at least because lights are switched off early.

Suppose each person uses a 50W bulb for his/her lighting. Also suppose that person sleeps two hours earlier than his/her regular timings. So he/she saves 50Wx2hrs=100 W.h of electrical energy per day (Computers and other gadgets are not counted because early sleepers rise early and starts their computers early ). In an year, a person can save 365×100 W.h = 36.5 KW.h . The general transmission losses of most power distributions is 10%. So the actual electricity produced to serve 36.5 KW.h is 40.15 KW.h . Emission Factor of Coal 0.963 i.e to generate 1 KW.h of electricity 0.963 Kg of CO₂ is emitted. Similarly E.F of Oil and Natural Gas are 0.881 and 0.569.

Production of energy varies from country to country. India used 53% of coal, 0.9% Oil and 10.5% Natural Gas(NG).
So the final formula to calculate the CO₂ emission cut would be

PowerOfAppliance(in KWatts)*HoursSavedPerYear* 1.1 (transmission loss)*E.F of Fossil Fuels

where E.F of Fossil Fuels= (%of Coal * E.F of Coal + %of Oil * E.F of Oil + %of NG * E.F of NG)/100

So if a person sleeps two hours earlier than their normal time of 12 or 1am, then that person (if in India) can prevent 23.325 Kgs of CO₂ from entering the atmosphere per year. This is just 0.015% of India’s total CO₂ emission assuming there are a crore people in India who can sleep two hours earlier. So it is very very insignificant. But when compared to per capita CO₂ emission of India which is 1310 kgs per year, then 23kgs savings per year per person accounts to 1.7%. Remember the calculations I did are the least possible savings we could do assuming just one 50W bulb. In reality, what we save will be more and varies according to our lifestyle, proximity to a thermal power station or a hydro electric power station, efficiency of the lights used. Also if the trend of whole city sleeping early is observed then most of the brilliant lighting (definitely more than 1000W) of the malls/shopping complexes will be switched off. The 23 kgs figure is the minimum we can definitely prevent from entering the atmosphere by sleeping early.

My point is: Why become responsible even for that insignificant 20 odd kgs of CO₂ emission per year when clearly almost all of the things that we generally do late night (reading books, chatting with friends, watching movies, playing games etc) can be done after sunrise and before 10 PM?

PS: The third widget from the top in the right side panel helps you figure out how much CO₂ emission per year can be prevented by saving electricity. (be it early sleeping, switching off the unnecessary devices or shutting half the lights of the malls/shopping complexes earlier than their normal close time etc ) Indian electricity production distribution is set as default.