COAL
Coal is a readily combustible black or brownish-black sedimentary rock. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. It is composed primarily of carbon along with variable quantities of other elements, chiefly sulfur, hydrogen, oxygen and nitrogen.
Coal was formed from plant remains that were protected by water and mud against oxidization and biodegradation, thus trapping atmospheric carbon in the ground. Over time, the chemical and physical properties of the remains were changed by geological action to create a solid material.
Coal, a fossil fuel, is the largest source of energy for the generation of electricity worldwide, as well as one of the largest worldwide anthropogenic sources of carbon dioxide emissions. Gross carbon dioxide emissions from coal usage are slightly more than those from petroleum and about double the amount from natural gas.[1] Coal is extracted from the ground by mining, either underground or in open pits.
When coal is used for electricity generation, it is usually pulverized and then burned in a furnace with a boiler. The furnace heat converts boiler water to steam, which is then used to spin turbines which turn generators and create electricity. The thermodynamic efficiency of this process has been improved over time. "Standard" steam turbines have topped out with some of the most advanced reaching about 35% thermodynamic efficiency for the entire process, although newer combined cycle plants can reach efficiencies as high as 58%. Increasing the combustion temperature can boost this efficiency even further.[11] Old coal power plants, especially "grandfathered" plants, are significantly less efficient and produce higher levels of waste heat. About 40% of the world's electricity comes from coal,[12] and approximately 49% of the United States electricity comes from coal.[13]
The emergence of the supercritical turbine concept envisions running a boiler at extremely high temperatures and pressures with projected efficiencies of 46%, with further theorized increases in temperature and pressure perhaps resulting in even higher efficiencies.[14]
Other efficient ways to use coal are combined cycle power plants, combined heat and power cogeneration, and an MHD topping cycle.
Approximately 40% of the world electricity production uses coal. The total known deposits recoverable by current technologies, including highly polluting, low energy content types of coal (i.e., lignite, bituminous), is sufficient for many years. However, consumption is increasing and maximal production could be reached within decades (see World Coal Reserves, below).
A more energy-efficient way of using coal for electricity production would be via solid-oxide fuel cells or molten-carbonate fuel cells (or any oxygen ion transport based fuel cells that do not discriminate between fuels, as long as they consume oxygen), which would be able to get 60%–85% combined efficiency (direct electricity + waste heat steam turbine).[citation needed] Currently these fuel cell technologies can only process gaseous fuels, and they are also sensitive to sulfur poisoning, issues which would first have to be worked out before large scale commercial success is possible with coal. As far as gaseous fuels go, one idea is pulverized coal in a gas carrier, such as nitrogen. Another option is coal gasification with water, which may lower fuel cell voltage by introducing oxygen to the fuel side of the electrolyte, but may also greatly simplify carbon sequestration. However, this technology has been criticised as being inefficient, slow, risky and costly, while doing nothing about total emissions from mining, processing and combustion.[15] Another efficient and clean way of coal combustion in a form of coal-water slurry fuel (CWS) was well developed in Russia (since the Soviet Union time). CWS significantly reduces emissions saving the heating value of coal.
In 2006, China was the top producer of coal with 38% share followed by the USA and India, reports the British Geological Survey.
The 930 billion short tons of recoverable coal reserves estimated by the Energy Information Administration are equal to about 4,116 BBOE (billion barrels of oil equivalent).[citation needed] The amount of coal burned during 2007 was estimated at 7.075 billion short tons, or 133.179 quadrillion BTU's[48]. In terms of heat content, this is about 57 million barrels of oil equivalent per day. By comparison in 2007, natural gas provided 51 million barrels of oil equivalent per day, while oil provided 85.8 million barrels per day.
British Petroleum, in its annual report 2007, estimated at 2006 end, there were 909,064 million tons of proven coal reserves worldwide, or 147 years reserves-to-production ratio. This figure only includes reserves classified as "proven"; exploration drilling programs by mining companies, particularly in under-explored areas, are continually providing new reserves. In many cases, companies are aware of coal deposits that have not been sufficiently drilled to qualify as "proven". However, some nations haven't updated their information and assume reserves remain at the same levels even with withdrawals.
Of the three fossil fuels coal has the most widely distributed reserves; coal is mined in over 100 countries, and on all continents except Antarctica. The largest reserves are found in the USA, Russia, Australia, China, India and South Africa.
Note the table below.
Taken from Wikimedia.org
Coal is a readily combustible black or brownish-black sedimentary rock. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. It is composed primarily of carbon along with variable quantities of other elements, chiefly sulfur, hydrogen, oxygen and nitrogen.
Coal was formed from plant remains that were protected by water and mud against oxidization and biodegradation, thus trapping atmospheric carbon in the ground. Over time, the chemical and physical properties of the remains were changed by geological action to create a solid material.
Coal, a fossil fuel, is the largest source of energy for the generation of electricity worldwide, as well as one of the largest worldwide anthropogenic sources of carbon dioxide emissions. Gross carbon dioxide emissions from coal usage are slightly more than those from petroleum and about double the amount from natural gas.[1] Coal is extracted from the ground by mining, either underground or in open pits.
Uses today
Coal rail cars
Coal as fuel
Further information: Electricity generation, Clean coal technology, Coal electricity, and Global warming
Coal is primarily used as a solid fuel to produce electricity and heat through combustion. World coal consumption is about 6.2 billion tons annually. China produced 2.38 billion tons in 2006 and India produced about 447.3 million tons in 2006. 68.7% of China's electricity comes from coal. The USA consumes about 1.053 billion tons of coal each year, using 90% of it for generation of electricity.[10] The world in total produced 6.19 billion tons of coal in 2006.When coal is used for electricity generation, it is usually pulverized and then burned in a furnace with a boiler. The furnace heat converts boiler water to steam, which is then used to spin turbines which turn generators and create electricity. The thermodynamic efficiency of this process has been improved over time. "Standard" steam turbines have topped out with some of the most advanced reaching about 35% thermodynamic efficiency for the entire process, although newer combined cycle plants can reach efficiencies as high as 58%. Increasing the combustion temperature can boost this efficiency even further.[11] Old coal power plants, especially "grandfathered" plants, are significantly less efficient and produce higher levels of waste heat. About 40% of the world's electricity comes from coal,[12] and approximately 49% of the United States electricity comes from coal.[13]
The emergence of the supercritical turbine concept envisions running a boiler at extremely high temperatures and pressures with projected efficiencies of 46%, with further theorized increases in temperature and pressure perhaps resulting in even higher efficiencies.[14]
Other efficient ways to use coal are combined cycle power plants, combined heat and power cogeneration, and an MHD topping cycle.
Approximately 40% of the world electricity production uses coal. The total known deposits recoverable by current technologies, including highly polluting, low energy content types of coal (i.e., lignite, bituminous), is sufficient for many years. However, consumption is increasing and maximal production could be reached within decades (see World Coal Reserves, below).
A more energy-efficient way of using coal for electricity production would be via solid-oxide fuel cells or molten-carbonate fuel cells (or any oxygen ion transport based fuel cells that do not discriminate between fuels, as long as they consume oxygen), which would be able to get 60%–85% combined efficiency (direct electricity + waste heat steam turbine).[citation needed] Currently these fuel cell technologies can only process gaseous fuels, and they are also sensitive to sulfur poisoning, issues which would first have to be worked out before large scale commercial success is possible with coal. As far as gaseous fuels go, one idea is pulverized coal in a gas carrier, such as nitrogen. Another option is coal gasification with water, which may lower fuel cell voltage by introducing oxygen to the fuel side of the electrolyte, but may also greatly simplify carbon sequestration. However, this technology has been criticised as being inefficient, slow, risky and costly, while doing nothing about total emissions from mining, processing and combustion.[15] Another efficient and clean way of coal combustion in a form of coal-water slurry fuel (CWS) was well developed in Russia (since the Soviet Union time). CWS significantly reduces emissions saving the heating value of coal.
Production trends
Coal output in 2005
A coal mine in Wyoming, United States. The United States has the world's largest coal reserves.
World coal reserves
At the end of 2006 the recoverable coal reserves amounted around 800 or 900 gigatons. The United States Energy Information Administration gives world reserves as 930 billion short tons[44] (equal to 843 gigatons) as of 2006. At the current extraction rate, this would last 132 years.[45] However, the rate of coal consumption is annually increasing at 2-3% per year and, setting the growth rate to 2.5% yields an exponential depletion time of 56 years (in 2065).[46] At the current global total energy consumption of 15.7 terawatts,[47] there is enough coal to provide the entire planet with all of its energy for 37 years (assuming 0% growth in demand and ignoring transportation's need for liquid fuels).[original research?]The 930 billion short tons of recoverable coal reserves estimated by the Energy Information Administration are equal to about 4,116 BBOE (billion barrels of oil equivalent).[citation needed] The amount of coal burned during 2007 was estimated at 7.075 billion short tons, or 133.179 quadrillion BTU's[48]. In terms of heat content, this is about 57 million barrels of oil equivalent per day. By comparison in 2007, natural gas provided 51 million barrels of oil equivalent per day, while oil provided 85.8 million barrels per day.
British Petroleum, in its annual report 2007, estimated at 2006 end, there were 909,064 million tons of proven coal reserves worldwide, or 147 years reserves-to-production ratio. This figure only includes reserves classified as "proven"; exploration drilling programs by mining companies, particularly in under-explored areas, are continually providing new reserves. In many cases, companies are aware of coal deposits that have not been sufficiently drilled to qualify as "proven". However, some nations haven't updated their information and assume reserves remain at the same levels even with withdrawals.
US coal regions
Note the table below.
| Country | Bituminous & anthracite | SubBituminous & lignite | TOTAL | Share |
|---|---|---|---|---|
| USA | 111,338 | 135,305 | 246,643 | 27.1 |
| Russia | 49,088 | 107,922 | 157,010 | 17.3 |
| China | 62,200 | 52,300 | 114,500 | 12.6 |
| India | 90,085 | 2,360 | 92,445 | 10.2 |
| Australia | 38,600 | 39,900 | 78,500 | 8.6 |
| South Africa | 48,750 | 0 | 48,750 | 5.4 |
| Ukraine | 16,274 | 17,879 | 34,153 | 3.8 |
| Kazakhstan | 28,151 | 3,128 | 31,279 | 3.4 |
| Poland | 14,000 | 0 | 14,000 | 1.5 |
| Brazil | 0 | 10,113 | 10,113 | 1.1 |
| Germany | 183 | 6,556 | 6,739 | 0.7 |
| Colombia | 6,230 | 381 | 6,611 | 0.7 |
| Canada | 3,471 | 3,107 | 6,578 | 0.7 |
| Czech Republic | 2,094 | 3,458 | 5,552 | 0.6 |
| Indonesia | 740 | 4,228 | 4,968 | 0.5 |
| Turkey | 278 | 3,908 | 4,186 | 0.5 |
| Greece | 0 | 3,900 | 3,900 | 0.4 |
| Hungary | 198 | 3,159 | 3,357 | 0.4 |
| Pakistan | 0 | 3,300 | 3,300 | 0.3 |
| Bulgaria | 4 | 2,183 | 2,187 | 0.2 |
| Thailand | 0 | 1,354 | 1,354 | 0.1 |
| North Korea | 300 | 300 | 600 | 0.1 |
| New Zealand | 33 | 538 | 571 | 0.1 |
| Spain | 200 | 330 | 530 | 0.1 |
| Zimbabwe | 502 | 0 | 502 | 0.1 |
| Romania | 22 | 472 | 494 | 0.1 |
| Venezuela | 479 | 0 | 479 | 0.1 |
| TOTAL | 478,771 | 430,293 | 909,064 | 100.0 |
- Recent discoveries in the Thar region of Pakistan have given rise to a discovery of nearly 185 billion tonnes. [3]
[edit] Major coal producers
The reserve life is an estimate based only on current production levels for the countries shown, and makes no assumptions of future production or even current production trends.| Country | 2003 | 2004 | 2005 | 2006 | Share | Reserve Life (years) |
|---|---|---|---|---|---|---|
| China | 1722.0 | 1992.3 | 2204.7 | 2380.0 | 38.4 % | 48 |
| USA | 972.3 | 1008.9 | 1026.5 | 1053.6 | 17.0 % | 234 |
| India | 375.4 | 407.7 | 428.4 | 447.3 | 7.2 % | 207 |
| Australia | 351.5 | 366.1 | 378.8 | 373.8 | 6.0 % | 210 |
| Russia | 276.7 | 281.7 | 298.5 | 309.2 | 5.0 % | 508 |
| South Africa | 237.9 | 243.4 | 244.4 | 256.9 | 4.1 % | 190 |
| Germany | 204.9 | 207.8 | 202.8 | 197.2 | 3.2 % | 34 |
| Indonesia | 114.3 | 132.4 | 146.9 | 195.0 | 3.1 % | 25 |
| Poland | 163.8 | 162.4 | 159.5 | 156.1 | 90 | |
| Total World | 5187.6 | 5585.3 | 5886.7 | 6195.1 | 100 % | 142 |
See also: List of countries by coal production
[edit] Major coal exporters
| Country | 2003 | 2004 | 2005 | Share |
|---|---|---|---|---|
| Australia | 238.1 | 247.6 | 257.6 | .320 |
| Indonesia | 107.8 | 131.4 | 147.6 | .134 |
| China | 103.4 | 95.5 | 79.0 | .098 |
| South Africa | 78.7 | 74.9 | 77.5 | .096 |
| Russia | 41.0 | 55.7 | 62.3 | .077 |
| USA | 43.0 | 48.0 | 49.9 | .062 |
| Canada | 27.7 | 28.8 | 31.0 | .039 |
| Poland | 16.4 | 16.3 | 16.4 | .020 |
| Vietnam | N/A | 10.3 | 14.1 | .018 |
| Total | 713.9 | 764.0 | 804.2 | 1 |
Taken from Wikimedia.org
