Welcome to brain Stuff from house stuff works dot com, where smart happens. I am Marshall Brain With today's question, how much coal is required to run a one hundred watt lightbulb twenty four hours a day for a year. We can start answering this question by figuring out how much energy in kilowatt hours that lightbulb uses in one year. To do that, we multiply how much power it uses in kilowatts by the number of hours in a year.
That gives us point one kilowatts times eight thousand, seven hundred sixty hours in a year, or eight hundred seventy six kilowatt hours for the year. The thermal energy content of a typical ton of coal is six thousand, one hundred fifty kilowatt hours per ton. Although coal fired power plants are very efficient, they're still limited by the laws of thermo dynamics, so only about of that thermal energy and coal gets converted into electricity by the power plant.
So the actual electricity generated per ton of coal is forty of six thousand, one hundred fifty, or roughly kilowatt hours per ton of coal. With a little math, we get seven pounds of coal. The light are one hundred watt lightbulb for a year. Once you take line losses and a few other things into account, it takes about a pound of coal to produce a kilowatt hour of electricity in round numbers, that's a pretty big pile of coal. But let's look at what else gets produced to power
that light bulb. First of all, there's sulfur dioxide. Coal usually contains a little bit of sulfur and it's the main cause of acid rain. You get five pounds of that when you light a one hundred lightbulb for a year. Then there's nitrogen oxides. These cause smog and acid rain. They occur when the nitrogen in the area gets heated up during the burning process with the coal. You get about five pounds of that lighting your light bulb. And then you get the carbon dioxide, a greenhouse gas suspected
of causing global warming. You get one thousand, eight hundred fifty two pounds of carbon dioxide emitted into the atmosphere. Coal also produces smaller amounts of just about every element on the periodic table, including the radioactive ones. In fact, a coal burning power plant emits more radiation than a properly functioning nuclear power plant. A typical five hundred megawatt coal power plant produces three and a half billion kilowatt hours per year. That's enough energy for four million of
our light bulbs to operate year round. To produce this amount of electrical energy, the plant will burn something like one and a half million tons of coal. Be sure to check out our new video podcast, Stuff from the Future. Join how stuf work staff as we explore the most promising and perplexing possibilities of tomorrow. The housed Offers iPhone app has arrived. Download it today on iTunes.