While oil is the most utilized
energy source, coal is the largest resource and also the cheapest.
Knowing this you would think coal would be consumed more, but it is very
limited for may reasons. Coal lost
out to oil because oil is easy to ship and use in engines.
Also, dealing with the huge concern of greenhouse gases emissions, coal
releases the most carbon dioxide per BTU of all common fuels.
Coal can contain small amounts of
every element present on the periodic table, 102 different elements, and a
various array of toxic organic compounds. This
usually is not a problem because an extremely small fraction of the coal is
impure. Unfortunately, power plants
use large amounts of coal. For
example a plant with a 60% capacity factor that produces 1,000 MW consumes
approximately 2 million tons of coal per year.
Since such a large amount is consumed that fractional percent of
hazardous material has now become a problem.
Poisons can get emitted into our atmosphere.
Some of these contaminants could be sulfur, mercury, lead, arsenic,
beryllium, and sulfate which helps produce acid rain.
On top of that, just to show how hazardous coal can be, here’s an
example: some coal if burned
without special controls, releases more radioactive elements into the air that
any nuclear plant would under normal conditions.
This example is to show the hazard that coal can yield, do not think that
the local power plant is emitting this hazardous material.
At most power plants controls are used to eliminate contaminants from
entering the atmosphere.
There are five different types of coal. Here they are from oldest to youngest: anthracite or hard coal, bituminous coal or soft coal, sub bituminous coal, lignite or brown coal, and peat. Coal is found in seams within the Earth, the older the coal the deeper it will be from the surface. Coal must be mined underground or on the surface, which is called strip mining, to be removed. Environmental problems that can occur with mines is acid mine drainage and siltation. Acid mine drainage poisons streams for decades after a mine is closed off and reclaimed, which means the land is returned to it’s original contour. This process occurs because water gets in contact with acidic rocks that have been exposed in the mining process. Siltation occurs from strip mines that are poorly reclaimed. The silt can migrate to streams and be present for years.