eco otaku

Just the other day I was getting through the first chapter of Tim Flannerys book, The Weather Makers, and he spoke about the use of coal to produce energy. It was the really the first time that I have actually thought about the process in depth and how the energy is extracted. So I decided to do a little bit more research about Coal, the biggest contributer to climate change according to the IPCCs report.

 Coal is actually organic matter, dead plants, that is formed after millions of years of being layered under sediments with the right conditions. Because of its organic foundations, its not surprising that coal is largely made up of CO2. In the past, large quantaties of carbon dioxide have been produced into the atmosphere, this CO2 has been stored within the earths surface. Coal is one of these reserves of CO2 that can be harmful when released into the atmosphere rather than being domant underground. Coal is actually between 60 and 90 percent CO2 (1).

Jeff Goodwell, author of “Big Coal: The dirty secret behind Americas energy future” comments in the Washinton Post (5) that

Digging up hard-to-get coal will also devastate Appalachia, where huge mountaintop-removal mines have already buried 700 miles of streams and 400,000 acres of forests. (Mountaintop-removal is a particularly destructive form of mining in which entire mountains are blasted apart to expose the coal seams inside; the rubble is typically dumped in nearby valleys.)

 The mining is also difficult and dangerous, with each year many major accidents occuring throughout the world. Furthermore the use of it to produce energy creates harmful pollution from power plants such a mercury (brain damage, birth defects) and Sulfure Dioxide (acid rain) (5).

When coal is used for making electricity. The coal is usually ground down to a powder before being burnt in large furnaces. The heat from these furnaces boils large quantaties of water which inturn creates steam. This steam powers large turbines that channel electricity via copper wire. The process is said to have a 35 percent efficiency, with a lot of heat being lost and thus wasted. Although according to the Siemens website, recently built coal power plants can have up to 58 percent efficiency (2).

This really made me think, if the coal is only the fuel for the fire, and its effects are harmful, why is its use continued? Renewable sources can achieve the same levels of electricity production through similar techniques. For instance, Geothermal, uses heat from the earths centre to heat water to produce steam for turbines. Solar photothermal uses a combination of mirrors that channel the suns rays into a collective heat source to heat its water for turbines. While steam has a higher density than air, water has a much higher density than steam, which makes tidal energy look very appealing. While there is a claim by coal producers that surverys show that there is enough coal for the next 250 years of energy uses, much of the easy coal has already been sourced and used. What is left is buried deep under forests and cities which is much more difficult to mine (5). Why would we choose such a path of destruction? Because its cheap? 

1-http://tonto.eia.doe.gov/energyexplained/index.cfm?page=coal_home

2-http://w1.siemens.com/responsibility/en/environment/portfolio/fossil_power_generation.htm

3-http://www.worldcoal.org/coal/where-is-coal-found/

4-http://www.eia.doe.gov/cneaf/electricity/epa/figes1.html

5-Washington Post Article – Jeff Goodell