Coal to Electric - Texas
Have you ever wondered how a lump of coal can generate electricity? It is amazing that so many people know nothing about a process that affects so much of what we do in our daily lives. According to the American Coal Foundation, more than fifty percent of the electricity that is used in our country comes from coal. How does this black rock bring light to more than half the homes in America?
Coal is a non-renewable fossil fuel. It is not something that can be reproduced during our lifetime, as it takes millions of years to form. It is made up of plant material that has been subjected to intense heat and pressure for extensive periods of time. Carbon is what gives coal most of its energy and it is what coal releases when burned. This release of carbon is what puts coal at the center of controversy among environmentalists.
The first step in turning coal to electricity is mining it. It is usually dug out of underground mines. Next, it is generally cleaned before being transported to a power plant. Once it reaches the power plant, there are a few ways that coal can be converted to electricity. There is what is called pulverized coal combustion. According to www.coal.org, almost all of the electricity powered by coal is produced this way. With this method, the coal is first crushed into a fine powder. Next, it is blown into a boiler where it is combusted to make steam. The steam then spins a turbine engine, which powers a generator.
There are some newer processes as well, like fluidized bed combustion where coal is put into "a bed of particles suspended in air that react with the coal" and make steam. There are combine-cycle systems as well, in which "gas produced by heating coal operates a combustion turbine connected to a generator and the exhaust gases from this turbine heat water" (American Coal Foundation). IGCC, or Integrated Coal Gasification Combined Cycle may be the most promising new process. This process breaks apart gases forging cleaner combustion.
According to the American Coal Foundation, the Department of Energy is working both with the coal industry and the electrical generation industry to find cleaner, more efficient ways to use coal. According to www.coal.org, "the average thermal efficiency of U.S. power plants has increased from 5% in 1900, to around 35% currently." While any steps in the direction of greater efficiency is a good thing, more needs to be done.
Not surprisingly, the American Coal Foundation sees coal as superior to other resources. For one, they say, the U.S. has a huge supply of it-so big, in fact, they estimate that if we continue to use coal at the rate at which we use it today, we have enough to last us 300 years. The American Coal Foundation also points to coal's versatility. It can be used as a solid or a gas, unlike natural gas. The foundation also points to the fact that coal is often cheaper than other options.
The Environmental Protection Agency gives us a look at some of the down sides of coal. For one, dangerous gases including carbon dioxide and nitrogen oxides are released when coal is burned. There is also the fact that coal mining and coal-fired power plants use a lot of water. Between cleaning the impurities and the large amount of water needed to produce steam, these power plants draw water from the lakes and rivers nearby which can disrupt the local ecosystem. Water can also be affected negatively in a different way. If it is pumped back into the lakes and rivers near the plant, pollutants that have built up in it can severely damage wildlife. Run off from piles of coal stored outside can also be harmful.
Like anything else, there are good and bad sides to using coal for electricity. To decide if it is the right type of power for you, it is best to be as educated on the subject as possible. It's also important to know and recognize what is important to you. Are you deeply concerned with price? Or are you more affected by the environmental impact of the choices you make? Clearly, this becomes a personal choice based on your frame of reference.