Clean coal technology
Encyclopedia
Clean coal technology is a collection of technologies being developed to reduce the environmental impact of coal
energy generation. When coal is used as a fuel source, the gaseous emmissions generated by the thermal decomposition of the coal, include sulphur dioxide, nitrogen dioxide, carbon dioxide, and other chemical byproducts that vary depending of the type of the coal being used. These emmissions have been established to have a negative impact on the environment, contributing to acid rain or climate change. As a result, clean coal technologies are being developed to remove or reduce pollutant emissions to the atmosphere. Some of the techniques that would be used to accomplish this include chemically washing mineral
s and impurities from the coal, gasification
(see also IGCC
), treating the flue
gases with steam
to remove sulfur dioxide
, carbon capture and storage
technologies to capture the carbon dioxide from the flue gas
and dewatering lower rank coals (brown coals) to improve the calorific value, and thus the efficiency of the conversion into electricity
.
Clean coal technology usually addresses atmospheric problems resulting from burning coal. Historically, the primary focus was on sulfur dioxide and particulates, since it is the most important gas in the causation of acid rain
. More recent focus has been on carbon dioxide (due to its impact on global warming
) as well as other pollutants. Concerns exist regarding the economic viability of these technologies and the timeframe of delivery, potentially high hidden economic costs in terms of social and environmental damage, and the costs and viability of disposing of removed carbon and other toxic matter.
Coal, which is primarily used for the generation of electricity, is the second largest domestic contributor to carbon dioxide emissions in the USA. The public has become more concerned about global warming which has led to new legislation. The coal industry has responded by running advertising touting clean coal in an effort to counter negative perceptions and claiming more than $50 billion towards the development and deployment of "traditional" clean coal technologies over the past 30 years; and promising $500 million towards carbon capture and storage research and development.
The world's first "clean coal" power plant went on-line in September 2008 in Spremberg
, Germany
. The plant is owned by the swedish company Vattenfall
and has been built by the german firm Siemens
. The plant is called Schwarze Pumpe power station. The facility captures CO2 and acid rain producing sulfides, separates them, and compresses the CO2 into a liquid state. Plans are to inject the CO2 into depleted natural gas fields or other geological formations. This technology is considered not to be a final solution for CO2 reduction in the atmosphere, but provides an achievable solution in the near term while more desirable alternative solutions to power generation can be made economically practical.
Intergovernmental Panel on Climate Change
, the burning of coal, a fossil fuel
, is a major contributor to global warming
. (See the UN IPCC Fourth Assessment Report
). As 25.5% of the world's electrical generation in 2004 was from coal-fired generation (see World energy resources and consumption
), reaching the carbon dioxide reduction targets of the Kyoto Protocol
will require modifications to how coal is utilized.
Some in the coal industry and the U.S. Department of Energy refer to carbon capture and sequestration (CCS) as the latest in "clean coal" technologies. The "clean coal" terminology is generally not endorsed by professionals in CCS, and is actively opposed by environmental organizations that favor CCS. CCS is a means to capture carbon dioxide from any source, compress it to a dense liquid-like state, and inject and permanently store it underground. Currently, there are more than 80 carbon capture and sequestration projects underway in the United States. All components of CCS technology have been used for decades in conjunction with enhanced oil recovery and other applications; commercial-scale CCS is currently being tested in the U.S. and other countries. Proposed CCS sites are subjected to extensive investigation and monitoring to avoid potential hazards, which could include leakage of sequestered CO2 to the atmosphere, induced geological instability, or contamination of aquifers used for drinking water supplies.
Supporters of clean coal use the Great Plains Synfuels plant to support the technical feasibility of carbon dioxide sequestration. Carbon dioxide from the coal gasification is shipped to Canada where it is injected into the ground to aid in oil recovery. Supporters admit that carbon sequestration is expensive.
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
energy generation. When coal is used as a fuel source, the gaseous emmissions generated by the thermal decomposition of the coal, include sulphur dioxide, nitrogen dioxide, carbon dioxide, and other chemical byproducts that vary depending of the type of the coal being used. These emmissions have been established to have a negative impact on the environment, contributing to acid rain or climate change. As a result, clean coal technologies are being developed to remove or reduce pollutant emissions to the atmosphere. Some of the techniques that would be used to accomplish this include chemically washing mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s and impurities from the coal, gasification
Gasification
Gasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen, carbon dioxide and methane. This is achieved by reacting the material at high temperatures , without combustion, with a controlled amount of oxygen and/or steam...
(see also IGCC
Integrated Gasification Combined Cycle
An integrated gasification combined cycle is a technology that turns coal into gas—synthesis gas . It then removes impurities from the coal gas before it is combusted and attempts to turn any pollutants into re-usable byproducts. This results in lower emissions of sulfur dioxide, particulates, and...
), treating the flue
Flue
A flue is a duct, pipe, or chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors. In the United States, they are also known as vents and for boilers as breeching for water heaters and modern furnaces...
gases with steam
Steam
Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
to remove sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
, carbon capture and storage
Carbon capture and storage
Carbon capture and storage , alternatively referred to as carbon capture and sequestration, is a technology to prevent large quantities of from being released into the atmosphere from the use of fossil fuel in power generation and other industries. It is often regarded as a means of mitigating...
technologies to capture the carbon dioxide from the flue gas
Flue gas
Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produced at power plants...
and dewatering lower rank coals (brown coals) to improve the calorific value, and thus the efficiency of the conversion into electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
.
Clean coal technology usually addresses atmospheric problems resulting from burning coal. Historically, the primary focus was on sulfur dioxide and particulates, since it is the most important gas in the causation of acid rain
Acid rain
Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions . It can have harmful effects on plants, aquatic animals, and infrastructure. Acid rain is caused by emissions of carbon dioxide, sulfur dioxide and nitrogen...
. More recent focus has been on carbon dioxide (due to its impact on global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
) as well as other pollutants. Concerns exist regarding the economic viability of these technologies and the timeframe of delivery, potentially high hidden economic costs in terms of social and environmental damage, and the costs and viability of disposing of removed carbon and other toxic matter.
Coal, which is primarily used for the generation of electricity, is the second largest domestic contributor to carbon dioxide emissions in the USA. The public has become more concerned about global warming which has led to new legislation. The coal industry has responded by running advertising touting clean coal in an effort to counter negative perceptions and claiming more than $50 billion towards the development and deployment of "traditional" clean coal technologies over the past 30 years; and promising $500 million towards carbon capture and storage research and development.
The world's first "clean coal" power plant went on-line in September 2008 in Spremberg
Spremberg
Spremberg is a village near to the city of Hoyerswerda in the Spree-Neiße district of Brandenburg, Germany. The village was first mentioned in 1956. The village alone has only 9,588 Inhabitants, the hole region has 21,361 Inhabitants-Geography:...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
. The plant is owned by the swedish company Vattenfall
Vattenfall
Vattenfall is a Swedish power company. The name Vattenfall is Swedish for waterfall, and is an abbreviation of its original name, Royal Waterfall Board...
and has been built by the german firm Siemens
Siemens
Siemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...
. The plant is called Schwarze Pumpe power station. The facility captures CO2 and acid rain producing sulfides, separates them, and compresses the CO2 into a liquid state. Plans are to inject the CO2 into depleted natural gas fields or other geological formations. This technology is considered not to be a final solution for CO2 reduction in the atmosphere, but provides an achievable solution in the near term while more desirable alternative solutions to power generation can be made economically practical.
Clean coal and the environment
According to the United NationsUnited Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...
Intergovernmental Panel on Climate Change
Intergovernmental Panel on Climate Change
The Intergovernmental Panel on Climate Change is a scientific intergovernmental body which provides comprehensive assessments of current scientific, technical and socio-economic information worldwide about the risk of climate change caused by human activity, its potential environmental and...
, the burning of coal, a fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...
, is a major contributor to global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
. (See the UN IPCC Fourth Assessment Report
IPCC Fourth Assessment Report
Climate Change 2007, the Fourth Assessment Report of the United Nations Intergovernmental Panel on Climate Change , is the fourth in a series of reports intended to assess scientific, technical and socio-economic information concerning climate change, its potential effects, and options for...
). As 25.5% of the world's electrical generation in 2004 was from coal-fired generation (see World energy resources and consumption
World energy resources and consumption
]World energy consumption in 2010: over 5% growthEnergy markets have combined crisis recovery and strong industry dynamism. Energy consumption in the G20 soared by more than 5% in 2010, after the slight decrease of 2009. This strong increase is the result of two converging trends...
), reaching the carbon dioxide reduction targets of the Kyoto Protocol
Kyoto Protocol
The Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change , aimed at fighting global warming...
will require modifications to how coal is utilized.
Some in the coal industry and the U.S. Department of Energy refer to carbon capture and sequestration (CCS) as the latest in "clean coal" technologies. The "clean coal" terminology is generally not endorsed by professionals in CCS, and is actively opposed by environmental organizations that favor CCS. CCS is a means to capture carbon dioxide from any source, compress it to a dense liquid-like state, and inject and permanently store it underground. Currently, there are more than 80 carbon capture and sequestration projects underway in the United States. All components of CCS technology have been used for decades in conjunction with enhanced oil recovery and other applications; commercial-scale CCS is currently being tested in the U.S. and other countries. Proposed CCS sites are subjected to extensive investigation and monitoring to avoid potential hazards, which could include leakage of sequestered CO2 to the atmosphere, induced geological instability, or contamination of aquifers used for drinking water supplies.
Supporters of clean coal use the Great Plains Synfuels plant to support the technical feasibility of carbon dioxide sequestration. Carbon dioxide from the coal gasification is shipped to Canada where it is injected into the ground to aid in oil recovery. Supporters admit that carbon sequestration is expensive.
See also
- BiocharBiocharBiochar or terra preta is charcoal created by pyrolysis of biomass. Biochar is under investigation as an approach to carbon sequestration via bio-energy with carbon capture and storage. Biochar thus has the potential to help mitigate climate change, via carbon sequestration...
- Carbon capture and storageCarbon capture and storageCarbon capture and storage , alternatively referred to as carbon capture and sequestration, is a technology to prevent large quantities of from being released into the atmosphere from the use of fossil fuel in power generation and other industries. It is often regarded as a means of mitigating...
- Carbon sequestration
- Coal phase outCoal phase outA fossil fuel phase-out are plans for transport electrification, decommissioning of operating fossil fuel-fired power plants and prevention of the construction of new fossil-fuel-fired power stations. The purpose of this is to decrease the high concentration of greenhouse gas emissions, which are...
- Coal-water slurry fuelCoal-water slurry fuelCoal-water slurry fuel is a fuel which consists of fine coal particles suspended in water. Presence of water in CWS reduces harmful emissions into the atmosphere, makes the coal explosion-proof, makes use of coal equivalent to use of liquid fuel Coal-water slurry fuel (CWSF or CWS or CWF) is a...
- Energy developmentEnergy developmentEnergy development is the effort to provide sufficient primary energy sources and secondary energy forms for supply, cost, impact on air pollution and water pollution, mitigation of climate change with renewable energy....
- Fluidized bed combustionFluidized bed combustionFluidized bed combustion is a combustion technology used in power plants. Fluidized beds suspend solid fuels on upward-blowing jets of air during the combustion process. The result is a turbulent mixing of gas and solids. The tumbling action, much like a bubbling fluid, provides more effective...
- FuturegenFutureGenFutureGen is a US government project announced by President George W. Bush in 2003; its initial plan involved the construction of a near zero-emissions coal-fueled power plant to produce hydrogen and electricity while using carbon capture and storage....
- GreenwashGreenwashGreenwashing , or "green sheen", is a form of spin in which green PR or green marketing is deceptively used to promote the perception that a company's policies or products are environmentally friendly.-Usage:...
- James E. Hansen
- JEA Northside Generating Station (Jacksonville)
- Kyoto ProtocolKyoto ProtocolThe Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change , aimed at fighting global warming...
- Mitigation of global warmingMitigation of global warmingClimate change mitigation is action to decrease the intensity of radiative forcing in order to reduce the potential effects of global warming. Mitigation is distinguished from adaptation to global warming, which involves acting to tolerate the effects of global warming...
- Mountaintop removal mining
- Refined coalRefined coalRefined coal is the product of the application of a coal upgrading technology that removes moisture and certain pollutants from lower-rank coals such as sub-bituminous and lignite coals and raising their calorific values. Coal refining or upgrading technologies are typically pre-combustion...
- SyngasSyngasSyngas is the name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen. Examples of production methods include steam reforming of natural gas or liquid hydrocarbons to produce hydrogen, the gasification of coal, biomass, and in some types of waste-to-energy...
- Waste managementWaste managementWaste management is the collection, transport, processing or disposal,managing and monitoring of waste materials. The term usually relates to materials produced by human activity, and the process is generally undertaken to reduce their effect on health, the environment or aesthetics...