![Share-electricity-coal](https://upload.wikimedia.org/wikipedia/commons/8/84/Share-electricity-coal.svg)
A coal-fired power station or coal power plant is a
thermal power station
A thermal power station is a type of power station in which heat energy is converted to electrical energy. In a steam-generating cycle heat is used to boil water in a large pressure vessel to produce high-pressure steam, which drives a stea ...
which burns
coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when ...
to generate
electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...
. Worldwide, there are about 8,500 coal-fired power stations totaling over 2,000 gigawatts
capacity. They generate about a third of the
world's electricity,
but cause many illnesses and early deaths, mainly from
air pollution
Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different typ ...
.
A coal-fired power station is a type of
fossil fuel power station
A fossil fuel power station is a thermal power station which burns a fossil fuel, such as coal or natural gas, to produce electricity. Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy, wh ...
. The coal is usually
pulverized and then burned in a
pulverized coal-fired boiler A pulverized coal-fired boiler is an industrial or utility boiler that generates thermal energy by burning pulverized coal (also known as powdered coal or coal dust since it is as fine as face powder in cosmetic makeup) that is blown into the fireb ...
. The furnace heat converts boiler water to
steam, which is then used to spin
turbine
A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating ...
s that turn
generators. Thus chemical energy stored in coal is converted successively into
thermal energy
The term "thermal energy" is used loosely in various contexts in physics and engineering. It can refer to several different well-defined physical concepts. These include the internal energy or enthalpy of a body of matter and radiation; heat, de ...
,
mechanical energy
In physical sciences, mechanical energy is the sum of potential energy and kinetic energy. The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is ...
and, finally,
electrical energy.
Coal-fired power stations emit over 10
Gt of
carbon dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...
each year, about one fifth of world
greenhouse gas emissions
Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and ...
, so are the single largest
cause of climate change. More than half of all the coal-fired electricity in the world is generated in China. In 2020 the total number of plants started falling
as they are being retired in Europe and America although still being built in Asia, almost all in China. Some remain profitable because
costs to other people due to the
health and environmental impact of the coal industry
The health and environmental impact of the coal industry includes issues such as land use, waste management, water and air pollution, caused by the coal mining, processing and the use of its products. In addition to atmospheric pollution, coal ...
are not priced into the cost of generation, but there is the risk newer plants may become
stranded asset
Stranded assets are "assets that have suffered from unanticipated or premature write-downs, devaluations or conversion to liabilities". Stranded assets can be caused by a variety of factors and are a phenomenon inherent in the 'creative destructi ...
s. The
UN Secretary General
The secretary-general of the United Nations (UNSG or SG) is the chief administrative officer of the United Nations and head of the United Nations Secretariat, one of the six principal organs of the United Nations.
The role of the secretary-g ...
has said that
OECD
The Organisation for Economic Co-operation and Development (OECD; french: Organisation de coopération et de développement économiques, ''OCDE'') is an intergovernmental organisation with 38 member countries, founded in 1961 to stimulate e ...
countries should
stop generating electricity from coal by 2030, and the rest of the world by 2040.
History
![Edison Electric Light Station, Holborn Viaduct, London](https://upload.wikimedia.org/wikipedia/commons/8/82/Edison_Electric_Light_Station%2C_Holborn_Viaduct%2C_London.jpg)
The first coal-fired power stations were built in the late 19th century and used
reciprocating engine
A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common fea ...
s to generate
direct current
Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or eve ...
.
Steam turbines allowed much larger plants to be built in the early 20th century and
alternating current
Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...
was used to serve wider areas.
Transport and delivery of coal
![Grand Junction Trip 92007 098](https://upload.wikimedia.org/wikipedia/commons/0/06/Castle_Gate_Power_Plant%2C_Utah_2007.jpg)
Coal is delivered by highway truck,
rail
Rail or rails may refer to:
Rail transport
*Rail transport and related matters
*Rail (rail transport) or railway lines, the running surface of a railway
Arts and media Film
* ''Rails'' (film), a 1929 Italian film by Mario Camerini
* ''Rail'' ( ...
,
barge
Barge nowadays generally refers to a flat-bottomed inland waterway vessel which does not have its own means of mechanical propulsion. The first modern barges were pulled by tugs, but nowadays most are pushed by pusher boats, or other vessels ...
,
collier ship or
coal slurry pipeline. Generating stations are sometimes built next to a mine; especially one mining coal, such as
lignite, which is not valuable enough to transport long-distance; so may receive coal by
conveyor belt or massive
diesel-electric-drive
trucks
A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...
. A large coal train called a "unit train" may be 2 km long, containing 130-140 cars with around 100 tonnes of coal in each one, for a total load of over 10000 tonnes. A large plant under full load requires at least one coal delivery this size every day. Plants may get as many as three to five trains a day, especially in "peak season" during the hottest summer or coldest winter months (depending on local climate) when power consumption is high.
Modern unloaders use rotary dump devices, which eliminate problems with coal freezing in bottom dump cars. The unloader includes a train positioner arm that pulls the entire train to position each car over a coal hopper. The dumper clamps an individual car against a platform that swivels the car upside down to dump the coal. Swiveling couplers enable the entire operation to occur while the cars are still coupled together. Unloading a unit train takes about three hours.
Shorter trains may use railcars with an "air-dump", which relies on air pressure from the engine plus a "hot shoe" on each car. This "hot shoe" when it comes into contact with a "hot rail" at the unloading trestle, shoots an electric charge through the air dump apparatus and causes the doors on the bottom of the car to open, dumping the coal through the opening in the trestle. Unloading one of these trains takes anywhere from an hour to an hour and a half. Older unloaders may still use manually operated bottom-dump rail cars and a "shaker" attached to dump the coal.
A collier (cargo ship carrying coal) may hold of coal and takes several days to unload. Some colliers carry their own conveying equipment to unload their own bunkers; others depend on equipment at the plant. For transporting coal in calmer waters, such as rivers and lakes, flat-bottomed
barge
Barge nowadays generally refers to a flat-bottomed inland waterway vessel which does not have its own means of mechanical propulsion. The first modern barges were pulled by tugs, but nowadays most are pushed by pusher boats, or other vessels ...
s are often used. Barges are usually unpowered and must be moved by
tugboat
A tugboat or tug is a marine vessel that manoeuvres other vessels by pushing or pulling them, with direct contact or a tow line. These boats typically tug ships in circumstances where they cannot or should not move under their own power, su ...
s or
towboat
A pusher, pusher craft, pusher boat, pusher tug, or towboat, is a boat designed for pushing barges or car floats. In the United States, the industries that use these vessels refer to them as towboats. These vessels are characterized by a squar ...
s.
For start up or auxiliary purposes, the plant may use fuel oil as well. Fuel oil can be delivered to plants by
pipeline
Pipeline may refer to:
Electronics, computers and computing
* Pipeline (computing), a chain of data-processing stages or a CPU optimization found on
** Instruction pipelining, a technique for implementing instruction-level parallelism within a s ...
,
tanker,
tank car
A tank car ( International Union of Railways (UIC): tank wagon) is a type of railroad car (UIC: railway car) or rolling stock designed to transport liquid and gaseous commodities.
History
Timeline
The following major events occurred in ...
or truck. Oil is stored in vertical cylindrical steel tanks with capacities as high as . The
heavier no. 5 "bunker" and no. 6 fuels are typically steam-heated before pumping in cold climates.
Operation
![PowerStation3](https://upload.wikimedia.org/wikipedia/commons/f/f1/PowerStation3.svg)
As a type of
thermal power station
A thermal power station is a type of power station in which heat energy is converted to electrical energy. In a steam-generating cycle heat is used to boil water in a large pressure vessel to produce high-pressure steam, which drives a stea ...
, a coal-fired power station converts chemical energy stored in coal successively into
thermal energy
The term "thermal energy" is used loosely in various contexts in physics and engineering. It can refer to several different well-defined physical concepts. These include the internal energy or enthalpy of a body of matter and radiation; heat, de ...
,
mechanical energy
In physical sciences, mechanical energy is the sum of potential energy and kinetic energy. The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is ...
and, finally,
electrical energy. The coal is usually
pulverized and then burned in a
pulverized coal-fired boiler A pulverized coal-fired boiler is an industrial or utility boiler that generates thermal energy by burning pulverized coal (also known as powdered coal or coal dust since it is as fine as face powder in cosmetic makeup) that is blown into the fireb ...
. The heat from the burning pulverized coal converts boiler water to
steam, which is then used to spin
turbine
A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating ...
s that turn
generators. Compared to a thermal power station burning other fuel types, coal specific fuel processing and ash disposal is required.
For units over about 200
MW capacity, redundancy of key components is provided by installing duplicates of the forced and induced draft fans, air preheaters, and fly ash collectors. On some units of about 60 MW, two boilers per unit may instead be provided. The
hundred largest coal power stations range in size from 3,000MW to 6,700MW.
Fuel processing
Coal is prepared for use by crushing the rough coal to pieces less than 5 cm in size. The coal is then transported from the storage yard to in-plant storage silos by
conveyor belts at rates up to 4,000 tonnes per hour.
In plants that burn pulverized coal, silos feed coal to
pulverizer
A pulverizer or grinder is a mechanical device for the grinding of many different types of materials. For example, a pulverizer mill is used to pulverize coal for combustion in the steam-generating furnaces of coal power plants.
Types of coal p ...
s (coal mills) that take the larger 5 cm pieces, grind them to the consistency of
talcum powder
Talc, or talcum, is a clay mineral, composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent ...
, sort them, and mix them with primary combustion air, which transports the coal to the boiler furnace and preheats the coal in order to drive off excess moisture content. A 500 MW
e plant may have six such pulverizers, five of which can supply coal to the furnace at 250 tonnes per hour under full load.
In plants that do not burn pulverized coal, the larger 5 cm pieces may be directly fed into the silos which then feed either mechanical distributors that drop the coal on a traveling grate or the
cyclone burners, a specific kind of combustor that can efficiently burn larger pieces of fuel.
Boiler operation
Plants designed for
lignite (brown coal) are used in locations as varied as Germany,
Victoria, Australia
Victoria is a state in southeastern Australia. It is the second-smallest state with a land area of , the second most populated state (after New South Wales) with a population of over 6.5 million, and the most densely populated state in ...
, and
North Dakota
North Dakota () is a U.S. state in the Upper Midwest, named after the indigenous Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minnesota to the east, So ...
. Lignite is a much younger form of coal than black coal. It has a lower energy density than black coal and requires a much larger furnace for equivalent heat output. Such coals may contain up to 70% water and
ash, yielding lower furnace temperatures and requiring larger induced-draft fans. The firing systems also differ from black coal and typically draw hot gas from the furnace-exit level and mix it with the incoming coal in fan-type mills that inject the pulverized coal and hot gas mixture into the boiler.
Ash disposal
The ash is often stored in
ash pond
An ash pond, also called a coal ash basin or surface impoundment,U.S. Environmental Protection Agency (EPA), Washington, D.C. "Hazardous and Solid Waste Management System; Identification and Listing of Special Wastes; Disposal of Coal Combustion ...
s. Although the use of ash ponds in combination with air pollution controls (such as
wet scrubber
The term wet scrubber describes a variety of devices that remove pollutants from a furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the ...
s) decreases the amount of airborne pollutants, the structures pose serious health risks for the surrounding environment. Power utility companies have often built the ponds without
liners
"Liners" is a horticultural term referring to very young plants, usually grown for sale to retailers or wholesalers, who then grow them to a larger size before selling them to consumers. Liners are usually grown from seed, but may also be grown ...
, especially in the United States, and therefore chemicals in the ash can leach into
groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated ...
and surface waters.
Since the 1990s, power utilities in the U.S. have designed many of their new plants with dry ash handling systems. The dry ash is disposed in landfills, which typically include liners and groundwater monitoring systems. Dry ash may also be recycled into products such as concrete, structural fills for road construction and grout.
Fly ash collection
Fly ash is captured and removed from the flue gas by electrostatic precipitators or fabric bag filters (or sometimes both) located at the outlet of the furnace and before the induced draft fan. The fly ash is periodically removed from the collection hoppers below the precipitators or bag filters. Generally, the fly ash is pneumatically transported to storage silos and stored on site in
ash pond
An ash pond, also called a coal ash basin or surface impoundment,U.S. Environmental Protection Agency (EPA), Washington, D.C. "Hazardous and Solid Waste Management System; Identification and Listing of Special Wastes; Disposal of Coal Combustion ...
s, or transported by trucks or railroad cars to
landfills,
Bottom ash collection and disposal
At the bottom of the furnace, there is a hopper for collection of
bottom ash. This hopper is kept filled with water to quench the ash and clinkers falling down from the furnace. Arrangements are included to crush the
clinkers and convey the crushed clinkers and bottom ash to on-site ash ponds, or off-site to landfills. Ash extractors are used to discharge ash from municipal solid waste–fired boilers.
Flexibility
A well-designed
energy policy,
energy law
Energy laws govern the use and taxation of energy, both renewable and non-renewable. These laws are the primary authorities (such as caselaw, statutes, rules, regulations and edicts) related to energy. In contrast, energy policy refers to th ...
and
electricity market
In a broad sense, an electricity market is a system that facilitates the exchange of electricity-related goods and services. During more than a century of evolution of the electric power industry, the economics of the electricity markets had un ...
are critical for flexibility. Although technically the flexibility of some coal-fired power stations could be improved they are less able to provide
dispatchable generation
Dispatchable generation refers to sources of electricity that can be programmed ''on demand'' at the request of power grid operators, according to market needs. Dispatchable generators may adjust their power output according to an order.
Non-disp ...
than most
gas-fired power plant
A gas-fired power plant or gas-fired power station or natural gas power plant is a thermal power station which burns natural gas to generate electricity. Natural gas power stations generate almost a quarter of world electricity and a signifi ...
s. The most important flexibility is low minimum load, however some flexibility improvements may be more expensive than
renewable energy with
batteries.
Coal power generation
two-thirds of coal burned is to generate electricity.
In 2020 coal was the largest source of electricity at 34%.
Over half coal generation in 2020 was in China.
About 60% of electricity in China, India and Indonesia is from coal.
In 2020 worldwide 2059 GW of coal power was operational, 50 GW was commissioned, and 25 GW started construction (most of these three in China); and 38 GW retired (mostly USA and EU).
Efficiency
There are 4 main types of coal-fired power station in increasing order of efficiency are: subcritical,
supercritical, ultra-supercritical and
cogeneration
Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time.
Cogeneration is a more efficient use of fuel or heat, because otherwise- wasted heat from elec ...
(also called combined heat and power or CHP). Subcritical is the least efficient type, however recent innovations have allowed retrofits to older subcritical plants to meet or even exceed efficiency of supercritical plants.
Integrated gasification combined cycle design
Integrated gasification combined cycle (IGCC) is a coal power generation technology that uses a high pressure gasifier to turn coal (or other carbon based fuels) into pressurized gas—synthesis gas (syngas). Converting the coal to gas enables the use of a
combined cycle generator, typically achieving high efficiency. The IGCC process can also enable removal of some pollutants from the syngas prior to the power generation cycle. However, the technology is costly compared with conventional coal-fired power stations.
Carbon dioxide emissions
As coal is mainly
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...
, coal-fired power stations have a high
carbon intensity
An emission intensity (also carbon intensity or C.I.) is the emission rate of a given pollutant relative to the intensity of a specific activity, or an industrial production process; for example grams of carbon dioxide released per megajoule o ...
. On average, coal power stations emit far more
greenhouse gas per unit electricity generated compared with other energy sources (see also
life-cycle greenhouse-gas emissions of energy sources
Greenhouse gas emissions are one of the environmental impacts of electricity generation. Measurement of life-cycle greenhouse gas emissions involves calculating the global-warming potential of energy sources through life-cycle assessment. Thes ...
). In 2018 coal burnt to generate electricity emitted over 10 Gt
of the 34 Gt total from fuel combustion (the overall total greenhouse gas emissions for 2018 was 55 Gt e).
Mitigation
Phase out
From 2015 to 2020, although coal generation hardly fell in absolute terms, some of its market share was taken by wind and solar.
In 2020 only China increased coal power generation, and globally it fell by 4%.
The
UN Secretary General
The secretary-general of the United Nations (UNSG or SG) is the chief administrative officer of the United Nations and head of the United Nations Secretariat, one of the six principal organs of the United Nations.
The role of the secretary-g ...
has said that
OECD
The Organisation for Economic Co-operation and Development (OECD; french: Organisation de coopération et de développement économiques, ''OCDE'') is an intergovernmental organisation with 38 member countries, founded in 1961 to stimulate e ...
countries should stop generating electricity from coal by 2030 and the rest of the world by 2040, otherwise limiting global warming to 1.5 °C, a target of the
Paris Agreement, would be extremely difficult.
Phasing out in Asia can be a financial challenge as plants there are relatively young:
in China the co-benefits of closing a plant vary greatly depending on its location.
Ammonia co-firing
Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
has a high hydrogen density and is easy to handle. It can be used as storing carbon-free fuel in gas turbine power generation and help significantly reduce CO₂ emissions as a fuel.
In Japan, the first major four-year test project was started in June 2021 to develop technology to enable co-firing a significant amount of ammonia at a large-scale commercial coal-fired plant. However low-carbon hydrogen and ammonia is in demand for
sustainable shipping, which unlike electricity generation, has few other clean options.
Conversion
Some power stations are being converted to burn gas,
biomass or waste, and conversion to
thermal storage
Thermal energy storage (TES) is achieved with widely different technologies. Depending on the specific technology, it allows excess thermal energy to be stored and used hours, days, months later, at scales ranging from the individual process, ...
will be trialled in 2023.
Carbon capture
Retrofitting some existing coal-fired power stations with
carbon capture and storage
Carbon capture and storage (CCS) or carbon capture and sequestration is the process of capturing carbon dioxide (CO2) before it enters the atmosphere, transporting it, and storing it (carbon sequestration) for centuries or millennia. Usually th ...
was being considered in China in 2020, but this is very expensive,
reduces the energy output and for some plants is not technically feasible.
Pollution
![Coal power plant wastestreams - EPA](https://upload.wikimedia.org/wikipedia/commons/7/7c/Coal_power_plant_wastestreams_-_EPA.png)
In some countries pollution is somewhat controlled by
best available techniques
The best available technology or best available techniques (BAT) is the technology approved by legislators or regulators for meeting output standards for a particular process, such as pollution abatement. Similar terms are ''best practicable means ...
, for example those in the EU through its
Industrial Emissions Directive
The Industrial Emissions Directive (Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated pollution prevention and control)) is a European Union directive which commits Europea ...
. In the United States, coal-fired plants are governed at the national level by several air pollution regulations, including the
Mercury and Air Toxics Standards
Mercury commonly refers to:
* Mercury (planet), the nearest planet to the Sun
* Mercury (element), a metallic chemical element with the symbol Hg
* Mercury (mythology), a Roman god
Mercury or The Mercury may also refer to:
Companies
* Mercu ...
(MATS) regulation,
by
effluent guidelines Effluent Guidelines (also referred to as Effluent Limitation Guidelines (ELGs)) are U.S. national standards for wastewater discharges to surface waters and publicly owned treatment works (POTW) (also called municipal sewage treatment plants). The U ...
for water pollution,
and by solid waste regulations under the
Resource Conservation and Recovery Act
The Resource Conservation and Recovery Act (RCRA), enacted in 1976, is the principal federal law in the United States governing the disposal of solid waste and hazardous waste.United States. Resource Conservation and Recovery Act. , , ''et seq., ...
(RCRA).
Coal-fired power stations continue to pollute in lightly regulated countries; such as the
Western Balkans
The Balkans ( ), also known as the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throughout the who ...
, India, Russia and South Africa;
causing over a hundred thousand early deaths each year.
Local air pollution
Damage to health from
particulates
Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter (PM) or suspended particulate matter (SPM) – are microscopic particles of solid or liquid matter suspended in the air. The t ...
,
sulphur dioxide and
nitrogen oxide occurs mainly in Asia and is often due to burning low quality coal, such as
lignite, in plants lacking modern
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 produc ...
treatment.
[ Early deaths due to air pollution have been estimated at 200 per GW-year, however they may be higher around power plants where scrubbers are not used or lower if they are far from cities.
]
Water pollution
Pollutants such as heavy metals leaching into ground water from unlined coal ash
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when de ...
storage ponds or landfills pollute water, possibly for decades or centuries. Pollutant discharges from ash pond
An ash pond, also called a coal ash basin or surface impoundment,U.S. Environmental Protection Agency (EPA), Washington, D.C. "Hazardous and Solid Waste Management System; Identification and Listing of Special Wastes; Disposal of Coal Combustion ...
s to rivers (or other surface water bodies) typically include arsenic
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, ...
, lead, mercury, selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
, chromium, and cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...
.
Mercury emissions from coal-fired power plants can fall back onto the land and water in rain, and then be converted into methylmercury by bacteria. Through biomagnification
Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. This increase can occur as a ...
, this mercury can then reach dangerously high levels in fish. More than half of atmospheric mercury comes from coal-fired power plants.
Coal-fired power plants also emit sulfur dioxide and nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
. These emissions lead to acid rain, which can restructure food web
A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. Another name for food web is consumer-resource system. Ecologists can broadly lump all life forms into one o ...
s and lead to the collapse of fish and invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
populations.
Mitigation of local pollution
local pollution in China, which has by far the most coal-fired power stations, is forecast to be reduced further in the 2020s and 2030s, especially if small and low efficiency plants are retired early.
Economics
Subsidies
Coal power plants tend to serve as base load
The base load (also baseload) is the minimum level of demand on an electrical grid over a span of time, for example, one week. This demand can be met by unvarying power plants, dispatchable generation, or by a collection of smaller intermittent e ...
technology, as they have high availability factors, and are relatively difficult and expensive to ramp up and down. As such, they perform poorly in real-time energy markets
Energy markets are national and international regulated markets that deal specifically with the trade and supply of energy. Energy market may refer to an electricity market, but can also refer to other sources of energy. Typically energy developme ...
, where they are unable to respond to changes in the locational marginal price. In the United States, this has been especially true in light of the advent of cheap natural gas, which can serve as a fuel in dispatchable power plants that substitute the role of baseload on the grid.
In 2020 the coal industry was subsidized $US18 billion.
Finance
The largest backers are Chinese banks under the Belt and Road Initiative (BRI).
Capacity factors
In India capacity factors are below 60%. In 2020 coal-fired power stations in the United States had an overall capacity factor
The net capacity factor is the unitless ratio of actual electrical energy output over a given period of time to the theoretical maximum electrical energy output over that period. The theoretical maximum energy output of a given installation is def ...
of 40%; that is, they operated at a little less than half of their cumulative nameplate capacity.
Stranded assets
If global warming is limited to well below 2 °C as specified in the Paris Agreement, coal plant stranded asset
Stranded assets are "assets that have suffered from unanticipated or premature write-downs, devaluations or conversion to liabilities". Stranded assets can be caused by a variety of factors and are a phenomenon inherent in the 'creative destructi ...
s of over US$500 billion are forecast by 2050, mostly in China. In 2020 think tank Carbon Tracker
Carbon Tracker is a London-based not-for-profit think tank researching the impact of climate change on financial markets.
Carbon Tracker popularized the notion of a carbon bubble, which describes the incompatibility between the continued devel ...
estimated that 39% of coal-fired plants were already more expensive than new renewables and storage and that 73% would be by 2025. about half of China's coal power companies are losing money and old and small power plants "have no hope of making profits". India is keeping potential stranded assets operating by subsidizing them.
Politics
In May 2021, the G7 committed to end support for coal-fired power stations within the year.
The energy policy of China regarding coal and coal in China are the most important factors regarding the future of coal-fired power stations, because the country has so many. According to one analysis local officials overinvested in coal-fired power in the mid-2010s because central government guaranteed operating hours and set a high wholesale electricity price.
In democracies coal power investment follows an environmental Kuznets curve
The Kuznets curve () expresses a hypothesis advanced by economist Simon Kuznets in the 1950s and 1960s. According to this hypothesis, as an economy develops, market forces first increase and then decrease economic inequality.
The Kuznets curve ...
. The energy policy of India about coal is an issue in the politics of India
Politics of India works within the framework of the country's Constitution. India is a parliamentary democratic secular republic in which the president of India is the head of state & first citizen of India and the prime minister of India is t ...
.
Protests
Protests have often been at mining sites and at sites of proposed new plants.
See also
* Powering Past Coal Alliance
The Powering Past Coal Alliance (PPCA) is a group of 166 countries, cities, regions and organisations aiming to accelerate the fossil-fuel phase out of coal-fired power stations, except the very few which have carbon capture and storage. It ha ...
* Global Energy Monitor
Global Energy Monitor (GEM) is a San Francisco-based non-governmental organization which catalogs fossil fuel and renewable energy projects worldwide. GEM shares information in support of clean energy and its data and reports on energy trends ...
References
External links
Coal fired power plant
Energy Education by the University of Calgary
The University of Calgary (U of C or UCalgary) is a public research university located in Calgary, Alberta, Canada. The University of Calgary started in 1944 as the Calgary branch of the University of Alberta, founded in 1908, prior to being ins ...
How a coal plant works video
by the Tennessee Valley Authority
The Tennessee Valley Authority (TVA) is a federally owned electric utility corporation in the United States. TVA's service area covers all of Tennessee, portions of Alabama, Mississippi, and Kentucky, and small areas of Georgia, North Carolin ...
How a coal plant works video
by Ontario Power Generation
Ontario Power Generation Inc. (OPG) is a Crown corporation and "government business enterprise" that is responsible for approximately half of the electricity generation in the province of Ontario, Canada. It is wholly owned by the governmen ...
Electricity from coal
by the World Coal Association
World's coal power plants mapped
by Carbon Brief
Carbon Brief is a UK-based website specialising in the science and policy of climate change. It has won awards for investigative journalism and data visualisation. Leo Hickman is the director and editor for Carbon Brief.
Founding
Carbon Brief ...
End Coal
by various environmental, social justice and health advocates
Coal-fired power
by the International Energy Agency
Economics of coal
by Carbon Tracker
Carbon Tracker is a London-based not-for-profit think tank researching the impact of climate change on financial markets.
Carbon Tracker popularized the notion of a carbon bubble, which describes the incompatibility between the continued devel ...
Centre for Research on Energy and Clean Air
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Coal-fired power stations
Greenhouse gas emissions