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were achieved by the development of pulverized coal firing and cyclone furnaces whichenhanced the thermal efficiency . The basic principle for coal based generation units is what is called by steam coal or thermal coalwhich is the steam created from boiling the water using coal as fuel source. Figure 2 belowshows the electricity generation process from coal:Figure 2: Cola power generation processThe process is started by crushing the coal into fine powder which easier and quicker to burn.After the coal is burnt at high temperatures, the heat energy is used to evaporate water in theboiler in order to produce steam that is passed into a steam turbine casing it to rotate. Thegenerator, which is mounted at one end of the steam turbine, will rotate and start producingelectricity . Coal plays a vital role in electricity generation in the US and worldwide where currently almost39% of US electricity is supplied from coal . Coal power plants have many advantages thatmakes it a desirable source of electricity. Abundancy and low cost of coal helped its spreadingespecially in the developing countries. Moreover, since it is an old and well known technologythat have made it easier in terms of operation and maintenance which enhanced the safety factoras well. Finally, the thermal efficiency of coal based power units could reach up to 41% which isconsidered high compared to other types of technologies .5
AHMED ALOTHMAN 10/26/2015 EE444ID # 2517115966Electric Power Generation ReportHowever, despite of these advantages, coal has many drawbacks which have made it startedlosing its popularity and people’s dependency on coal power plants. One of the biggest effects ofcoal power plants is the gas emissions that releases toxic gases to the environment (e.g. SulfurDioxide, Carbon Monoxide, Carbon Dioxide, Mercury and Selenium) causing some dangerouseffects like acid rain and global warming effect. Because of these hazardous impacts, USregulatory authorities started applying some environmental regulations and production reductionon these coal based power plants . Many advancements and developments are being done on coal power station design and newcombustion technologies which are aiming to improve the thermal efficiency and reducing theCO2 emissions. One of these technologies which has been developed in china is called“Advanced Ultra-supercritical Coal-fired Power Generation Technology” which is improvingthe thermal efficiency of coal power plants to reach up to 50% . A one percentage pointimprovement in the thermal efficiency of a conventional coal combustion plant results in a 2-3%reduction in CO2 emissions . B.Natural GasNatural gas was first introduced to the electricity generation with the invention of steam turbineby Sir Charles Parsons in the 19thcentury with a capacity of 7.5 kW . In the 1990’s, naturalgas has become the fuel of choice for new power plants due to economic “low prices”,environmental “few emissions” compared with coal and technological changes .