How much mercyry or CO2 is emitted from the power plant ?
Assume the powerplant is burning clean carbon, what release about 30MJ of heat per burned kg.
The typical plant efficiency is about 50%, what mean output of 15MJ per kg of burned carbon.
The mass of the carbon atom is 12, of the oxygen atom is 16, so the burning 1kg of carbon release 3.7kg of CO2.
So we have about 4MJ of electricity per kg of CO2 emission.
But all that numbers are quite optimistic, as other components of coal reduce the heat output per kg of contained carbon...
With 100W incandescent lamp burned for 6000hours it mean about 540kg of CO2, so about 150kg of burned carbon.
For the mercury release it depend, how much is the mercury content in the coal...
In 40W T12 switch start fixture, 40W is lamp only or lamp + ballast ? How much W lamp + how much W ballast ?
The 40W is power input of the tube only (assume unity BF), ballast losses are in the 10..20W range, so 50..60W total.
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How does this change when the lamp is replaced with 36W T8 ?
The power delivered to the tube is 36W, ballast losses about the same, so overall power input is 46..56W
Is the 430mA rating of the ballast for 40W only and actual current is lower for 36W ? (what confuses me here is that the newer ballasts dropped the 40W rating and left with the 36W only (though they can run 40W) and the current rating is still 430mA unchanged)
The current is the same for both lamps (to be more exact, the 36W would run on slightly higher current then the 40W with exactly the same ballast, it's temperature and mains voltage, but the difference is less then a percent, so way below other tolerances of the system parameters)