CARBON EMMISION FROM COAL BASED THERMAL POWER PLANTS PROCESS OF EMMISION, CAUSES OF HIGH CARBON EMMISION FROM INDIAN POWER PLANTS AND POSSIBILITIES & STEPS TO REDUCE IT Presented By: Shikhar Singh, Prashant Kashyap and Rishabh P S Gurjar, 2nd Year Students, Department of Mining Engg.

WHAT IS CARBON EMISSION? Carbon emission is the release of carbon into the atmosphere. Emitted carbon is mostly of the form CO or CO2. When coal is burnt, it releases many harmful green house gases of which CO2 is a major part. In coal based thermal power plants a huge amount of carbon emission takes place due to burning of coal.

ANALYSIS OF THE PROBLEM The problem basically focuses on the emission of green house gases from coal based thermal power plants of which carbon in the form of CO2 is a major part. Due to rapid increase in emission of green house gases and mainly CO2 from these power plants the need for analyzing and controlling it has become a task of huge importance. In this case study we have discussed on the following three aspects of the problem: Process of Carbon emission from Coal based thermal power plants. Causes of high rate of Carbon emission from Indian power plants. Various possibilities and steps to reduce the Carbon emission.

PROCESS OF CARBON EMISSION When pulverized coal burns, it emits enormous quantities of carbon dioxide along with other pollutants like sulfur dioxide, nitrogen oxide, mercury, and microscopic particulate matter. Almost all coal plants operating today use “pulverized coal” (PC) technology. Introduction of gasification combined cycle (IGCC) technology.

Emitted GHGs Process GHG emission from a coal based thermal power plant

SCENARIO IN INDIA India ranks third in world coal production, producing 293,497.15 metric tons (mt) of coal in 2012. The majority of this production, approximately 85%, is used for thermal power generation. Electricity from coal currently accounts for 71% of India’s total 67 gigawatts of power generated. India ranks 4th in carbon emission, generating 1.67 metric tonnes (mt) of CO2 in the year 2010.

Region wise CO2 Emission by thermal Power Plants Source: Ministry of Power (http://www.powermin.nic.in/)

CAUSES OF HIGH RATE OF CARBON EMISSION

Indian coal is of poor quality and often contain 30-50% ash when shipped to power stations.

Deteriorating Quality of Indian Coal Calorific value and the ash content of thermal coals in India have deteriorated as the better quality coal reserves are depleted and surface mining and mechanization expand. Deteriorating Quality of Indian Coal 1970s 1980s 1990s Fixed Carbon 36.5% 32.4% 25% Volatile matter 25.5% 21.6% 18% Moisture 10% 16% 12% Ash 28% 30% 45% High heating value (kcal/kg) 4,750 4,050 3,000 Source: www.frontline.in Volume 25 - Issue 22 :: Oct. 25-Nov. 07, 2008

Majority of the coal production, approximately 70%, is used for thermal power generation.

India has been slower than other countries in embracing carbon emission reduction as part of normal operating practices in thermal power generation.

REDUCING CARBON EMISSION

Retirement or renovation of old and inefficient plants. Suggestions made by CEA in one of its reports on thermal power plants RETIREMENT: In one of its reports on energy efficiency in thermal power stations CEA has suggested that the units which are deviating more from design should retire first. Retirement is linked to commissioning of new units. RENOVATION: To restore rated capacity and design parameters such as Heat Rate, APC, SOC etc.. To make the operating units well equipped with modified/ augmented latest technology. To improve the performance parameters in terms of PLF, Efficiency, Forced Outages, Availability and Reliability.

Efficiency improvement by accelerating installation of supercritical/ultra supercritical (SC/USC) plants. A supercritical steam generator is a type of boiler that operates at supercritical pressure, frequently used in the production of electric power. Source IEA, 2006

Introduction of tighter air pollution norms. Introduction of the Clean Power Plan in USA. The Clean Power Plan establishes state by state targets for carbon emissions reductions. It offers a flexible framework under which states may meet those targets. According to CPP green house gases have been considered as pollutants that "endanger public health and welfare." The final version of the rule would reduce national electricity sector emissions by an estimated 32 percent below 2005 levels by 2030.

COAL BENEFICIATION It is a process by which the quality of raw coal is improved by either reducing the extraneous matter that gets extracted along with the mined coal or reducing the associated ash or both

Advantages: Economics of Coal Beneficiation the bid price for coal washing services has been as low as Rs105 per raw ton. This is mostly because of intense competition by coal transporters and agents. Advantages: Increased power generation. Sustainable, highly efficient power generation. Increased rail way transport capacity. Lower pollution emissions .

Case Studies and Findings The case study of Dadri Power Plant (4x210 mw), NTPC which uses washed coal with around 34-35% ash from Central Coalfield Limited’s Piparwar washery demonstrates the qualitative and quantitative benefits of coal beneficiation : Increase in overall efficiency; up to 1.2% Saving in land area for ash dumping; 1 acre per year Reduction in CO2 emissions (reduced transportations/coal combustion; > 600,000 ton/yr.

CARBON CAPTURE AND SEQUESTRATION PROCESS OF CARBON CAPTURE It is the process of capturing waste carbon dioxide (CO2) from large point sources, such as fossil fuel power plants, transporting it to a storage site, and depositing it where it will not enter the atmosphere.

OUTCOMES OF CSS SYSTEM According to the 2005 Annual Report of IPCC, the emissions from power plants reduced by upto 87% after the installation of CCS system.

Initiatives taken by Govt. of India A capacity of 27,485 MW based on supercritical technology has already been Commissioned and 49,925 MW super critical capacity is under construction. All coal fired capacity additions shall be based on supercritical technology in the 13th Plan. Renovation, Modernization and Life Extension of old thermal power generating units and retirement of old and inefficient thermal generation units, in phased manner, has been undertaken. Introduction of PAT Scheme.

CONCLUSION National norms for PM are very weak and need to be brought in line with global standards(like the CPP programme of USA). Applying more stress on the applications of coal beneficiation methods. Approvals for new capacities should be only for supercritical/ultra supercritical plants. Old, inefficient plants should be closed at an aggressive pace. Stress on application of Carbon Capture and Sequestration process should be increased.

REFERENCES Ministry of Power, Government of India, Annual Report 2001-02 & 2008-09 (www.powermin.nic.in) Government of India, Central Electricity Authority, 11th Plan Shelf of Thermal Power Projects,(www.cea.nic.in) CSE report on “Heat on power-green rating of coal based thermal power plants”. International Energy Agency (IEA) www.iea.org/ US Environmental Protection Agency, www.epa.gov

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