Coal

 Carboniferous Period~ million years ago  Dead plants-> sunk to bottom of swamps- >formed peat->covered by sand and clay- >sedimentary rock  Increase in material stacked on top=more weight->pressed down on peat->squeezed until water came out->over millions of years turned into coal, oil, petroleum or natural gas

1. Highly concentrated organic material 2. Organic material must be cut off from oxygen 3. Organic material be arranged in a way that enhances its energy content

 Conventional Fossil Fuels  least expensive to produce  Supply nearly all energy provided by fossil fuels  Ex: coal, oil, and natural gas  Unconventional Fossil Fuels  More expensive to produce  May replace conventional once they are depleted  Ex: oil shales and tar sands

 Wood shortage in Europe during 16 th century  17 th and 18 th centuries- developed technologies to make steel and steam engines that used coal  Powered the industrial revolution

 Coal- more energy per unit  Coal- more noxious gas (difficult to burn in confined spaces with poor ventilation)  Coal- needed to be mined, unlike wood  Coal- harder to ignite

 Formed from remains of once living plants and animals->highly concentrated organic material  Coastal and inland swamps 40 degrees north and south of equator

1. Anthracite  90% carbon  million Btu/ton 2. Bituminous  million Btu/ton 3. Lignite  13 million Btu/ton  Relatively immature- can sometimes see woody plant material

1. Underground mining  2 or more shafts down to deposit  One shaft to move miners, coal, and materials; other for ventilation  One of the most hazardous jobs in US and throughout world

2. Mountaintop Removal  Vegetation and soil are removed  Set off multiple explosions->separates coal from the rocks

3. Surface Mining  Remove soil and rock above coal seam  Bulldozers put coal into dump trunks  Transported onto trains or mixed with water and moved through pipelines-> expensive

 United States holds the world's largest estimated recoverable reserves of coal and is a net exporter of coal.  US coal mines produced over a billion short tons of coal- more than 90% of this coal used by U.S. power plants to generate electricity.

 Before 1977, surface coal mining landowners had abandoned 1.1 million coal mine sites in the United States

 Balances the need to protect the environment from the adverse effects of surface coal mining with the Nation's need for coal as an essential energy source.  Operations are conducted in an environmentally responsible manner and that the land is adequately reclaimed during and following the mining process

 While coal has been the largest source of electricity generation for over 60 years, its annual share of generation declined from 49% in 2007 to 42% in 2011 as some power producers switched to lower-priced natural gas.

 Produced in 25 states spread across three coal- producing regions.  In 2011, approximately 72% of production originated in five states: Wyoming, West Virginia, Kentucky, Pennsylvania, and Texas.

 More than 1,400 coal-fired electricity generating units in operation at more than 600 plants across the country.  Generate over 40% of the electricity produced in the United States and consume more than 900 million short tons of coal per year.

 Produces several types of emissions that adversely affect the environment  sulfur dioxide, nitrogen oxide, and heavy metals (such as mercury and arsenic) and acid gases (such as hydrogen chloride), which have been linked to acid rain, smog, and health issues.  Emits carbon dioxide, a greenhouse gas.

 In 2011, coal accounted for 34% of the energy- related carbon dioxide emissions in the United States.  On the production-side, coal mining can have a negative impact on ecosystems and water quality, and alter landscapes and scenic views

 Outflow of acidic water from a mining site  Major problem with many hard rock mines, including almost all mines where the metal ore is bound up with sulfur.  metals dissolved by the acid drainage poison downstream waters

 Many river systems and former mine sites are totally inhospitable to aquatic life, with the exception of "extremophile" bacteria.  ecological destruction in watersheds and the contamination of human water sources by sulfuric acid and heavy metals, including arsenic, copper, and lead

 Coal Mining Coal Mining