First American Scientific Corp. (fka FASC)

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How Much Coal is Required to Run a 100 Watt Light Bulb 24 Hours a Day for a Year. (Answer 714 pounds)
Following the procedure used by the reference above, powering a 100 watt light bulb for ONE hour requires .0813 pounds (1.3 ounces) of coal. Burning that 1.3 ounces of coal generates about .21 pounds (3.36 ounces) of Carbon Dioxide (about three times the weight of the coal that went in, because it combines with air when it burns).
Solid coal (not broken up) has a density of the nature of 85 pounds per cubic foot (or .79 ounces per cubic inch). The 1.3 ounces required to burn a 100 watt light bulb for one hour would be about 1 cubic inch of coal. Normally coal is broken up and "piled" at power plants. Piled coal has a density in the range of about 50 pounds per cubic foot.

At 70 degrees Fahrenheit and atmospheric pressure, Carbon Dioxide gas has a specific gravity of 8.74 cubic feet per pound. Inverting, we obtain a density of .114 pounds per cubic foot (.00106 ounces per cubic inch). The 3.36 ounces of Carbon Dioxide generated by burning the 100 watt light bulb for one hour would occupy about 3170 cubic inches (1.8 cubic feet) at 70 degrees Fahrenheit and atmospheric pressure. Note - this is over 3000 times the volume of the coal burned to keep the 100 watt bulb on for one hour.