Electrical energy is energy related to forces on electrically charged particles and the movement of those particles (often electrons in wires, but not always). This energy is supplied by the combination of current and electric potential (often referred to as voltage because electric potential is measured in volts ) that is delivered by a circuit (e.g., provided by an electric power utility). Motion (current) is not required; for example, if there is a voltage difference in combination with charged particles, such as static electricity or a charged capacitor , the moving electrical energy is typically converted to another form of energy (e.g., thermal, motion, sound, light, radio waves, etc.).
54-778: Stokes Hill Power Station was an oil-fired thermal power station in Darwin, Northern Territory , Australia . During its operating life, it was the largest power station in the Northern Territory, although it was considered unreliable and highly inefficient. Stokes Hill's high operating costs required government to heavily subsidise power bills for Darwin residents, who frequently experienced supply disruptions. Design specifications in 1957 forecast that demand could initially be met by two turbo-alternator units of 74 MW each, with an additional smaller unit of 15 MW capacity expected to be required by 1971. At its opening on 14 June 1962 however,
108-460: A greenhouse gas which is a major contributor to global warming . The results of a recent study show that the net income available to shareholders of large companies could see a significant reduction from the greenhouse gas emissions liability related to only natural disasters in the United States from a single coal-fired power plant. However, as of 2015, no such cases have awarded damages in
162-630: A cooler cooling system. However, it may be used in cogeneration plants to heat buildings, produce hot water, or to heat materials on an industrial scale, such as in some oil refineries , plants, and chemical synthesis plants. Typical thermal efficiency for utility-scale electrical generators is around 37% for coal and oil-fired plants, and 56 – 60% (LEV) for combined-cycle gas-fired plants. Plants designed to achieve peak efficiency while operating at capacity will be less efficient when operating off-design (i.e. temperatures too low.) Practical fossil fuels stations operating as heat engines cannot exceed
216-404: A cooler medium must be equal or larger than the ratio of absolute temperatures of the cooling system (environment) and the heat source (combustion furnace). Raising the furnace temperature improves the efficiency but complicates the design, primarily by the selection of alloys used for construction, making the furnace more expensive. The waste heat cannot be converted into mechanical energy without
270-503: A factory or data center, or may also be operated in parallel with the local utility system to reduce peak power demand charge from the utility. Diesel engines can produce strong torque at relatively low rotational speeds, which is generally desirable when driving an alternator , but diesel fuel in long-term storage can be subject to problems resulting from water accumulation and chemical decomposition . Rarely used generator sets may correspondingly be installed as natural gas or LPG to minimize
324-487: A fine filter that collects the ash particles, electrostatic precipitators use an electric field to trap ash particles on high-voltage plates, and cyclone collectors use centrifugal force to trap particles to the walls. A recent study indicates that sulfur emissions from fossil fueled power stations in China may have caused a 10-year lull in global warming (1998-2008). Fossil-fuel power stations, particularly coal-fired plants, are
378-478: A fossil fuel power plant the chemical energy stored in fossil fuels such as coal , fuel oil , natural gas or oil shale and oxygen of the air is converted successively into thermal energy , mechanical energy and, finally, electrical energy . Each fossil fuel power plant is a complex, custom-designed system. Multiple generating units may be built at a single site for more efficient use of land , natural resources and labor . Most thermal power stations in
432-636: A major source of industrial wastewater . Wastewater streams include flue-gas desulfurization, fly ash, bottom ash and flue gas mercury control. Plants with air pollution controls such as wet scrubbers typically transfer the captured pollutants to the wastewater stream. Ash ponds , a type of surface impoundment, are a widely used treatment technology at coal-fired plants. These ponds use gravity to settle out large particulates (measured as total suspended solids ) from power plant wastewater. This technology does not treat dissolved pollutants. Power stations use additional technologies to control pollutants, depending on
486-408: A particular fuel. As an example, a new 1500 MW supercritical lignite-fueled power station running on average at half its capacity might have annual CO 2 emissions estimated as: = 1500MW x 0.5 x 100/40 x 101000 kg/TJ x 1year = 1500MJ/s x 0.5 x 2.5 x 0.101 kg/MJ x 365x24x60x60s = 1.5x10 x 5x10 x 2.5 x 1.01 x 3.1536x10 kg = 59.7 x10 kg = 5.97 Mt Thus the example power station
540-447: A reciprocating gas engine . All plants use the energy extracted from the expansion of a hot gas, either steam or combustion gases. Although different energy conversion methods exist, all thermal power station conversion methods have their efficiency limited by the Carnot efficiency and therefore produce waste heat . Fossil fuel power stations provide most of the electrical energy used in
594-433: A serious impact on public health. Power plants remove particulate from the flue gas with the use of a bag house or electrostatic precipitator . Several newer plants that burn coal use a different process, Integrated Gasification Combined Cycle in which synthesis gas is made out of a reaction between coal and water. The synthesis gas is processed to remove most pollutants and then used initially to power gas turbines. Then
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#1733114693825648-481: Is a deceiving baseline for comparison: just the Chernobyl nuclear disaster released, in iodine-131 alone, an estimated 1.76 EBq. of radioactivity, a value one order of magnitude above this value for total emissions from all coal burned within a century, while the iodine-131, the major radioactive substance which comes out in accident situations, has a half life of just 8 days. Electrical energy Electrical energy
702-424: Is a relatively cheap fuel. Coal is an impure fuel and produces more greenhouse gas and pollution than an equivalent amount of petroleum or natural gas. For instance, the operation of a 1000-MWe coal-fired power plant results in a nuclear radiation dose of 490 person-rem/year, compared to 136 person-rem/year for an equivalent nuclear power plant, including uranium mining, reactor operation and waste disposal. Coal
756-419: Is burned that significant amounts of these substances are released. A 1,000 MW coal-burning power plant could have an uncontrolled release of as much as 5.2 metric tons per year of uranium (containing 74 pounds (34 kg) of uranium-235 ) and 12.8 metric tons per year of thorium. In comparison, a 1,000 MW nuclear plant will generate about 30 metric tons of high-level radioactive solid packed waste per year. It
810-550: Is caused by the emission of nitrogen oxides and sulfur dioxide . These gases may be only mildly acidic themselves, yet when they react with the atmosphere, they create acidic compounds such as sulfurous acid , nitric acid and sulfuric acid which fall as rain, hence the term acid rain. In Europe and the US, stricter emission laws and decline in heavy industries have reduced the environmental hazards associated with this problem, leading to lower emissions after their peak in 1960s. In 2008,
864-428: Is converted to steam in the boiler; additional heating stages may be included to superheat the steam. The hot steam is sent through controlling valves to a turbine. As the steam expands and cools, its energy is transferred to the turbine blades which turn a generator. The spent steam has very low pressure and energy content; this water vapor is fed through a condenser, which removes heat from the steam. The condensed water
918-403: Is delivered by highway truck , rail , barge , collier ship or coal slurry pipeline . Generating stations adjacent to a mine may receive coal by conveyor belt or massive diesel-electric -drive trucks . Coal is usually prepared for use by crushing the rough coal to pieces less than 2 inches (5 cm) in size. Gas is a very common fuel and has mostly replaced coal in countries where gas
972-499: Is estimated that during 1982, US coal burning released 155 times as much uncontrolled radioactivity into the atmosphere as the Three Mile Island incident . The collective radioactivity resulting from all coal burning worldwide between 1937 and 2040 is estimated to be 2,700,000 curies or 0.101 EBq. During normal operation, the effective dose equivalent from coal plants is 100 times that from nuclear plants. Normal operation however,
1026-421: Is estimated to emit about 6 megatonnes of carbon dioxide each year. The results of similar estimations are mapped by organisations such as Global Energy Monitor , Carbon Tracker and ElectricityMap. Alternatively it may be possible to measure CO 2 emissions (perhaps indirectly via another gas) from satellite observations. Another problem related to coal combustion is the emission of particulates that have
1080-646: Is referred to as a combined cycle power plant because it combines the Brayton cycle of the gas turbine with the Rankine cycle of the HRSG. The turbines are fueled either with natural gas or fuel oil. Diesel engine generator sets are often used for prime power in communities not connected to a widespread power grid. Emergency (standby) power systems may use reciprocating internal combustion engines operated by fuel oil or natural gas. Standby generators may serve as emergency power for
1134-464: Is still important as the fuel source for diesel engine power plants used especially in isolated communities not interconnected to a grid. Liquid fuels may also be used by gas turbine power plants, especially for peaking or emergency service. Of the three fossil fuel sources, oil has the advantages of easier transportation and handling than solid coal, and easier on-site storage than natural gas. Combined heat and power (CHP), also known as cogeneration ,
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#17331146938251188-502: Is still unknown as to which kinds of particulate matter pose the most harm, which makes it difficult to come up with adequate legislation for regulating particulate matter. There are several methods of helping to reduce the particulate matter emissions from coal-fired plants. Roughly 80% of the ash falls into an ash hopper, but the rest of the ash then gets carried into the atmosphere to become coal-fly ash. Methods of reducing these emissions of particulate matter include: The baghouse has
1242-459: Is the " nameplate capacity " or the maximum allowed output of the plant, " capacity factor " or "load factor" is a measure of the amount of power that a plant produces compared with the amount it would produce if operated at its rated capacity nonstop, heat rate is thermal energy in/electrical energy out, emission intensity (also called emission factor ) is the CO 2 emitted per unit of heat generated for
1296-536: Is the use of a thermal power station to provide both electric power and heat (the latter being used, for example, for district heating purposes). This technology is practiced not only for domestic heating (low temperature) but also for industrial process heat, which is often high temperature heat. Calculations show that Combined Heat and Power District Heating (CHPDH) is the cheapest method in reducing (but not eliminating) carbon emissions, if conventional fossil fuels remain to be burned. Thermal power plants are one of
1350-433: Is then pumped into the boiler to repeat the cycle. Emissions from the boiler include carbon dioxide, oxides of sulfur, and in the case of coal fly ash from non-combustible substances in the fuel. Waste heat from the condenser is transferred either to the air, or sometimes to a cooling pond, lake or river. One type of fossil fuel power plant uses a gas turbine in conjunction with a heat recovery steam generator (HRSG). It
1404-482: Is usually sold by the kilowatt hour (1 kW·h = 3.6 MJ) which is the product of the power in kilowatts multiplied by running time in hours. Electric utilities measure energy using an electricity meter , which keeps a running total of the electric energy delivered to a customer. Electric heating is an example of converting electrical energy into another form of energy, heat . The simplest and most common type of electric heater uses electrical resistance to convert
1458-465: Is what remains after the coal has been combusted, so it consists of the incombustible materials that are found in the coal. The size and chemical composition of these particles affects the impacts on human health. Currently coarse (diameter greater than 2.5 μm) and fine (diameter between 0.1 μm and 2.5 μm) particles are regulated, but ultrafine particles (diameter less than 0.1 μm) are currently unregulated, yet they pose many dangers. Unfortunately much
1512-462: The Carnot cycle limit for conversion of heat energy into useful work. Fuel cells do not have the same thermodynamic limits as they are not heat engines. The efficiency of a fossil fuel plant may be expressed as its heat rate , expressed in BTU/kilowatthour or megajoules/kilowatthour. In a steam turbine power plant, fuel is burned in a furnace and the hot gasses flow through a boiler. Water
1566-810: The European Environment Agency (EEA) documented fuel-dependent emission factors based on actual emissions from power plants in the European Union . Electricity generation using carbon-based fuels is responsible for a large fraction of carbon dioxide (CO 2 ) emissions worldwide and for 34% of U.S. man-made carbon dioxide emissions in 2010. In the U.S. 70% of electricity is generated by combustion of fossil fuels. Coal contains more carbon than oil or natural gas fossil fuels, resulting in greater volumes of carbon dioxide emissions per unit of electricity generated. In 2010, coal contributed about 81% of CO 2 emissions from generation and contributed about 45% of
1620-460: The fossil fuels contains carbon dioxide and water vapor, as well as pollutants such as nitrogen oxides (NO x ), sulfur oxides (SO x ), and, for coal-fired plants, mercury , traces of other metals, and fly ash . Usually all of the carbon dioxide and some of the other pollution is discharged to the air. Solid waste ash from coal-fired boilers must also be removed. Fossil fueled power stations are major emitters of carbon dioxide (CO 2 ),
1674-436: The greenhouse gas carbon dioxide within the atmosphere will "very likely" lead to higher average temperatures on a global scale ( global warming ). Concerns regarding the potential for such warming to change the global climate prompted IPCC recommendations calling for large cuts to CO 2 emissions worldwide. Emissions can be reduced with higher combustion temperatures, yielding more efficient production of electricity within
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1728-668: The Commonwealth to the Northern Territory Electricity Commission (NTEC) when the Northern Territory achieved self-government in 1978. In addition to reliability issues and the high cost of oil, by this time base-load demand for electricity in Darwin was growing at a rate of 3.5% per annum. These factors led to NTEC seeking a site for a new, modern power station. The Channel Island site in Darwin Harbour 's Middle Arm
1782-518: The United States. Per unit of electric energy, brown coal emits nearly twice as much CO 2 as natural gas, and black coal emits somewhat less than brown. As of 2019 , carbon capture and storage of emissions is not economically viable for fossil fuel power stations, and keeping global warming below 1.5 °C is still possible but only if no more fossil fuel power plants are built and some existing fossil fuel power plants are shut down early, together with other measures such as reforestation . In
1836-423: The cycle. As of 2019 the price of emitting CO 2 to the atmosphere is much lower than the cost of adding carbon capture and storage (CCS) to fossil fuel power stations, so owners have not done so. The CO 2 emissions from a fossil fuel power station can be estimated with the following formula: CO 2 emissions = capacity x capacity factor x heat rate x emission intensity x time where "capacity"
1890-510: The electricity generated in the United States. In 2000, the carbon intensity (CO 2 emissions) of U.S. coal thermal combustion was 2249 lbs/MWh (1,029 kg/MWh) while the carbon intensity of U.S. oil thermal generation was 1672 lb/MWh (758 kg/MWh or 211 kg/ GJ ) and the carbon intensity of U.S. natural gas thermal production was 1135 lb/MWh (515 kg/MWh or 143 kg/GJ). The Intergovernmental Panel on Climate Change ( IPCC ) reports that increased quantities of
1944-514: The energy. There are other ways to use electrical energy. In computers for example, tiny amounts of electrical energy are rapidly moving into, out of, and through millions of transistors , where the energy is both moving (current through a transistor) and non-moving (electric charge on the gate of a transistor which controls the current going through). Electricity generation is the process of generating electrical energy from other forms of energy . The fundamental principle of electricity generation
1998-431: The first central stations used reciprocating steam engines to drive generators. As the size of the electrical load to be served grew, reciprocating units became too large and cumbersome to install economically. The steam turbine rapidly displaced all reciprocating engines in central station service. Coal is the most abundant fossil fuel on the planet, and widely used as the source of energy in thermal power stations and
2052-568: The fuel system maintenance requirements. Spark-ignition internal combustion engines operating on gasoline (petrol), propane , or LPG are commonly used as portable temporary power sources for construction work, emergency power, or recreational uses. Reciprocating external combustion engines such as the Stirling engine can be run on a variety of fossil fuels, as well as renewable fuels or industrial waste heat. Installations of Stirling engines for power production are relatively uncommon. Historically,
2106-460: The hot exhaust gases from the gas turbines are used to generate steam to power a steam turbine. The pollution levels of such plants are drastically lower than those of "classic" coal power plants. Particulate matter from coal-fired plants can be harmful and have negative health impacts. Studies have shown that exposure to particulate matter is related to an increase of respiratory and cardiac mortality. Particulate matter can irritate small airways in
2160-428: The lungs, which can lead to increased problems with asthma, chronic bronchitis, airway obstruction, and gas exchange. There are different types of particulate matter, depending on the chemical composition and size. The dominant form of particulate matter from coal-fired plants is coal fly ash , but secondary sulfate and nitrate also comprise a major portion of the particulate matter from coal-fired plants. Coal fly ash
2214-476: The main artificial sources of producing toxic gases and particulate matter . Fossil fuel power plants cause the emission of pollutants such as NO x , SO x , CO 2 , CO, PM, organic gases and polycyclic aromatic hydrocarbons. World organizations and international agencies, like the IEA, are concerned about the environmental impact of burning fossil fuels , and coal in particular. The combustion of coal contributes
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2268-488: The most to acid rain and air pollution , and has been connected with global warming . Due to the chemical composition of coal there are difficulties in removing impurities from the solid fuel prior to its combustion. Modern day coal power plants pollute less than older designs due to new " scrubber " technologies that filter the exhaust air in smoke stacks. However, emission levels of various pollutants are still on average several times greater than natural gas power plants and
2322-607: The particular wastestream in the plant. These include dry ash handling, closed-loop ash recycling, chemical precipitation, biological treatment (such as an activated sludge process), membrane systems, and evaporation-crystallization systems. In 2015 EPA published a regulation pursuant to the Clean Water Act that requires US power plants to use one or more of these technologies. Technological advancements in ion exchange membranes and electrodialysis systems has enabled high efficiency treatment of flue-gas desulfurization wastewater to meet
2376-545: The power station closed in the early hours of Christmas morning. Damage to the building by winds and storm surges resulted in flooding that damaged electrical equipment, while transmission lines and substations were completely destroyed. In the days immediately following the storm, small diesel generators were brought online at Stokes Hill in order to provide power to the old Darwin Hospital , located at Myilly Point in Larrakeyah . It
2430-530: The scrubbers transfer the captured pollutants to wastewater, which still requires treatment in order to avoid pollution of receiving water bodies. In these modern designs, pollution from coal-fired power plants comes from the emission of gases such as carbon dioxide, nitrogen oxides , and sulfur dioxide into the air, as well a significant volume of wastewater which may contain lead , mercury , cadmium and chromium , as well as arsenic , selenium and nitrogen compounds ( nitrates and nitrites ). Acid rain
2484-464: The station was only capable of generating 15 MW Within months of opening, it was already apparent that even the originally specified capacity would be insufficient to meet the growing demand. The Australian Bureau of Statistics indicate that by 1969, the power station was operating with four units, for a maximum installed capacity of 47 MW. By 1977, further upgrades had brought the capacity up to its ultimate 141 MW. When Cyclone Tracy hit Darwin in 1974,
2538-579: The updated EPA discharge limits. Coal is a sedimentary rock formed primarily from accumulated plant matter, and it includes many inorganic minerals and elements which were deposited along with organic material during its formation. As the rest of the Earth's crust , coal also contains low levels of uranium , thorium , and other naturally occurring radioactive isotopes whose release into the environment leads to radioactive contamination . While these substances are present as very small trace impurities, enough coal
2592-438: The world use fossil fuel, outnumbering nuclear , geothermal , biomass , or concentrated solar power plants. The second law of thermodynamics states that any closed-loop cycle can only convert a fraction of the heat produced during combustion into mechanical work . The rest of the heat, called waste heat , must be released into a cooler environment during the return portion of the cycle. The fraction of heat released into
2646-484: The world. Some fossil-fired power stations are designed for continuous operation as baseload power plants , while others are used as peaker plants . However, starting from the 2010s, in many countries plants designed for baseload supply are being operated as dispatchable generation to balance increasing generation by variable renewable energy . By-products of fossil fuel power plant operation must be considered in their design and operation. Flue gas from combustion of
2700-423: Was 28 petawatt-hours . A fossil fuel power station is a thermal power station which burns a fossil fuel , such as coal , oil , or natural gas , to produce electricity . Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy , which then operates an electrical generator . The prime mover may be a steam turbine , a gas turbine or, in small plants,
2754-559: Was discovered during the 1820s and early 1830s by the British scientist Michael Faraday . His basic method is still used today: electric current is generated by the movement of a loop of wire, or disc of copper between the poles of a magnet . For electrical utilities, it is the first step in the delivery of electricity to consumers. The other processes, electricity transmission , distribution , and electrical energy storage and recovery using pumped-storage methods are normally carried out by
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#17331146938252808-455: Was found in the late 20th century or early 21st century, such as the US and UK. Sometimes coal-fired steam plants are refitted to use natural gas to reduce net carbon dioxide emissions. Oil-fuelled plants may be converted to natural gas to lower operating cost. Heavy fuel oil was once a significant source of energy for electric power generation. After oil price increases of the 1970s, oil was displaced by coal and later natural gas. Distillate oil
2862-407: Was not until 25 January that power began to be restored to large parts of the city. Stokes Hill Power Station proved unreliable during its operational life, often unable to provide uninterrupted power supply for the city. A series of failures saw the power station supplemented with an additional 30 MW natural gas generator at Berrimah in 1979. Ownership of the power station was transferred from
2916-570: Was selected in 1981. The power station was decommissioned in 1987, following completion of the Channel Island Power Station . It sat dormant for nearly a decade until demolition was completed in 1997. Today, little trace of the power station is evident at the site, which is a short distance from the new Darwin Waterfront Precinct . Oil-fired power station 2021 world electricity generation by source. Total generation
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