Coal Formation

Coal types

• Peat: Youngest form of coal, lowest grade, low quality fuel and organic material for gardeners

• Lignite: 150 million yrs old, 50% carbon content

• Bituminous: 300 million years old, 50-80% carbon

• Anthracite: 500 million years old, 95% carbon, hardest and cleanest burning coal.

US Coal resources

World distribution of coal

World coal production

Problems with coal

• Like oil and natural gas it will not last forever• It is not a clean fuel source, lots of

environmental impact from using coal– Environmental effects of surface (strip) mining– CO2 (carbon dioxide) emissions impact

environment (green house effect)– SO2 (sulfer dioxide) emissions pose health risks

Shale oil and tar sands:Nonconventional fossil fuels

• Shale oil: largest deposit is found in the Green River Formation

• 50 million years ago, this area was covered by 2 large tropical lakes. Organic material at the bottom of the lakes combined with sediment and formed a carbon containing mudstone, called marlstone.

Green River Formation

Recovery methods• Getting the oil is not easy, nor is it cheap, thus as long

as there is abundant, cheaper coal, this resources will remain untapped

• Same amount of coal produces much more energy• Traditional removal process require heating (a process

called retorting) of the shale to remove the hydrocarbons which expands the remaining shale by 35%. Need a deposit site to handle the waste

• This process also requires lots of water, Green River formation is in a very dry part of the country.

• In situ (on site) recovery methods are being developed to overcome these difficulties