“I will honor Christmas in my heart, and try to keep it all the year.” – Charles Dickens, Ebenezer Scrooge, A Christmas Carol.
We all know the story of Ebenezer Scrooge and How the Grinch Stole Christmas. We’ve all watched a Charlie Brown’s Christmas, and a few of us have seen Tokyo Godfathers. But as we start the count down to the seasons (yes, lots of people begin the count down to the next one as soon as the previous one is over and some of us have already begun our Christmas shopping), I am left wondering why “naughty” children get coal for Christmas.
After all coal is a useful thing.
The Sicilian tradition tracks back to pre-Christian Italy. There, La Befana, an old woman, would go around and leave light and fluffy candy for “nice” children and pieces of a dark candy or coal for the “naughty” ones (Note: Most of the history of the legend is shrouded in the mist of time. Other places such as Holland have also claimed to have begun the ritual).
Coal has many more uses than being given to “naughty” children. In America it is mostly used to create electricity. You may ask yourself, “how do they produce electricity with a darkly colored piece of rock?” Good Question!! Here is how.
Coal is a combustible sedimentary rock that is made from decayed plant matter that accumulated at the bottom of bodies of water, such as ponds or swamps. Coal takes millions of years to form, so while there will be a little more available in the future neither I nor my 10^2,000,000 grandchild will be able to use it (her name will be Carol, by the way).
There are four main types of coal. Anthracite coal is around 90% carbon. Of the coals, it burns the hottest, but only makes up about half of a percent of the coal used. Bituminous coal makes up 50% of the coal production in the United States and is used to turn turbines to make electricity. Sub-bituminous coal accounts for about 46% of coal production, but does not produce as much heat as Bituminous. Lignite is the youngest of the coal and holds the least carbon. There are other types of coal and coal related rocks. Graphite is a coal, but its ignition point is so high, it is rarely used as fuel. Coal and diamonds are both carbon products, but it would take a Superman to make coal into diamonds while you watch.
Coal has been used for 6,000 years. Its first use was as jewelry in China. The Romans used it as a heating source. Coal is best known as being the fuel supply for the Industrial Revolution in Europe.
|Surface Coal Mine
photo credit: Neuwieser
Coal is usually found underground. Most coal mines in the United States are surface mined. A surface mine is where you remove the surface and dig a large open air pit to get to a deposit – in this case coal.
In the present day, coal is mainly used to produce electricity. About 40% of the world’s electricity and 50% of the United States’ electricity come from coal.
How does coal produce electricity? The coal is burned for its heat. The heat is used to turn water into steam. The steam is used to turn a turbine, which produces the electricity.
So how efficient is coal at producing energy? A kilogram of coal produces about 2 kilowatt hours of electricity. It would take about 1 ton of coal to run a 100 watt light bulb for a year. (Natural Gas produces about 3.1 kilowatt hours per kilogram.)
|photo credit: ReneS|
Coal when burned emits a lot of undesirable emissions. 2000 pounds (1 ton that is used to keep a light bulb on for a year) of coal will produce about 5,720 pounds of carbon dioxide. Burning coal also produce sulfur dioxide and nitrous oxide, both of which are harmful gases. Particulate matter, also know as fly ash, is left over as well.
So why would we use coal?
We use it here in America, because America has the largest coal reserves. It is somewhat easy to mine and does not require a lot of refining to make it a usable fuel. Also coal remains a cheap way to produce electricity.
America is no longer the largest user of coal. China surpassed America in coal consumption in 2008.
Over the years the coal industry has developed ways to capture the harmful gases. Scrubbers remove the sulfur before it can become sulfur dioxide and catalytic converters take out the nitrogen. The particulate matter is now collected and sold to different companies which include cement makers, embankment producers, and many others. They are also creating ways to capture and store the carbon dioxide before it enters the atmosphere. The captured carbon dioxide can be used for many different things including improved oil recovery and even conversion into fuel.
The use of coal in electricity production is projected to rise over time. It will rise mainly because the need for energy will rise. Energy consumption will continue to rise with population growth and industrial development.