Environmental Issues from Coal-Fired Power Plant - An Overview. (Public Paper)

This paper displays and discuss environmental issues related to coal-fired power plants in a holistic manner. Summary of applicable legal requirements in Malaysia are provided throughout the chronology of this industrial activity. Presented in public on April 24, 2012 in Impiana KLCC Hotel, Kuala Lumpur, Malaysia as invited speaker for Marlene Insurance Brokers Sdn Bhd in an event for Tenaga Nasional Berhad titled "Seminar On Power Utility Operations & Maintenance Management".

Example chemical structure of coal

Anthracite (Ibbenbüren, Germany)

Bituminous coal

Coal in its perceived abundance is a non-renewable resource. Despite banalities of protests it is still the main diet for power generation world wide. Interactions with the environment begins from deforestation activities in mining preparations. The chronology continues downstream to discharges, leachings and releases of its unwanted hazardous constituents from power plants into the respective environmental receptors. The ecosystem, especially its inhabitants and adjoining natural resources are susceptible to significant environmental impacts in unstoppable chain of effects. Pollution prevention and control involving technical innovations and legislations are contingencies to prevent, control or abate such impact. Within certain stages of its life-cycle are opportunities of using its waste forms as materials for other products. The pursuit for alternative renewable resources for energy is relentless. There’s a gleam of hope for fortuitous discovery of technologies with economic viablity. (The above pictures on Bituminous, Chemical Structure of Coal and Anthracite were sourced from:  http://en.wikipedia.org/wiki/Coal) 

KOTA KINABALU Feb 16 — Sabah has scrapped the controversial coal-fired power plant in Lahad Datu saying today it will look for alternative energy sources after a three year-long campaign by environmentalists. “I am pleased to announce that federal and state governments have agreed to pursue other alternative sources of energy namely gas to meet Sabah’s power supply needs ” Sabah Chief Minister Datuk Seri Musa Aman said in a statement released this afternoon “I know there have been certain objections to the proposed coal powered plant Today is proof that such objections have not fallen on deaf ears ” The Department of Environment DOE had rejected the detailed environmental impact assessment DEIA for the proposed RM1 3 billion 300-MW coal-fired plant in Felda Sahabat in August last year because many important environmental parameters in the proposed project were not addressed in the report. (1)

The powdered coal from the coal mills is carried to the boiler in coal pipes by high pressure hot air. The pulverized coal air mixture is burnt in the boiler in the combustion zone.
Generally in modern boilers tangential firing system is used i.e. the coal nozzles/ guns form tangent to a circle. The temperature in fire ball is of the order of 1300 deg.C. The boiler is a water tube boiler hanging from the top. Water is converted to steam in the boiler and steam is separated from water in the boiler Drum. The saturated steam from the boiler drum is taken to the Low Temperature Superheater, Platen Superheater and Final Superheater respectively for superheating. The superheated steam from the final superheater is taken to the High Pressure Steam Turbine (HPT). In the HPT the steam pressure is utilized to rotate the turbine and the resultant is rotational energy. From the HPT the out coming steam is taken to the Reheater in the boiler to increase its temperature as the steam becomes wet at the HPT outlet. After reheating this steam is taken to the Intermediate Pressure Turbine (IPT) and then to the Low Pressure Turbine (LPT). The outlet of the LPT is sent to the condenser for condensing back to water by a cooling water system. This condensed water is collected in the Hotwell and is again sent to the boiler in a closed cycle. The rotational energy imparted to the turbine by high pressure steam is converted to electrical energy in the Generator.

Deforestation.

 ·     global warming;

·     greenhouse effect;

·     anthropogenic carbon dioxide emissions;

·     reduces the content of water in the soil and groundwater as well as atmospheric moisture;

·     water runoff, which moves much faster than subsurface flows -  flash flooding;

·     increases rates of soil erosion;

·    reduced biodiversity, medicinal conservation;

Trees, and plants in general, affect the water cycle significantly:

§  their canopies intercept a proportion of precipitation, which is then evaporated back to the atmosphere (canopy interception);

§  their litter, stems and trunks slow down surface runoff;

§  their roots create macropores – large conduits – in the soil that increase infiltration of water;

§  they contribute to terrestrial evaporation and reduce soil moisture via transpiration;

§  their litter and other organic residue change soil properties that affect the capacity of soil to store water.

their leaves control the humidity of the atmosphere by transpiring. 99% of the water absorbed by the roots moves up to the leaves and is transpired.

Legal liability

·       Mountain-top deforestation for mining purposes in Malaysia is subjected to EIA as classified under Forestry as “ Conversion of hill forest land to other land use covering an area of 50 hectares or more.” Or under Order-2, Environmental Quality (Prescribed Activities) (Environmental Impact Assessment) Order, 1987. The ‘Schedule’.

·       Mining as “Mining of minerals in new area where the mining lease covers a total area in excess of 250 hectares.” – Order-2, Environmental Quality (Prescribed Activities) (Environmental Impact Assessment) Order, 1987. The ‘Schedule’.

Judicial liability for not providing the EIA report as projects gets underway is RM100,000.00 and/or 5 years imprisonment.

Mountains are geological structures that serves as the strongest civil structure that holds the earth crust. They are rocks of different formation and composition that emerged from their respective plates that forms the earth surface. Mountain ranges form in a process called orogenesis, where two tectonic plates meet.(34)

By nature they are dynamic and thus unstable as natural forces are constantly applying pressure from below its geological settings. However, science haven’t finish learning about them and can’t make much accurate prediction of their behaviour. Nonetheless, their desirable constituents to man are known and named. They include minerals and metals like palladium, titanium, uranium (4)(5), gold etc., and of cause oil and coal. Coal mining generates significant additionally independent adverse environmental health impacts, among them the water pollution flowing from mountaintop removal mining.(2)

§  Release of methane, a greenhouse; gas causing climate change;

§  Waste products, including uranium, thorium, and other radioactive and heavy metal contaminants;

§  Acid Mine Drainage (AMD);

§  Interference; with groundwater and water table levels;

§  Impact of water use on flows of rivers and consequent impact on other land uses;

§  Dust;

§  Tunnels sometimes damage infrastructure (e.g. roads);

§  Land rendered unsuitable for other use.

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Pollutants for which indirect exposure is especially important include mercury, arsenic, dioxins, cadmium and lead. Mercury contamination of fish (and subsequent consumption by humans) is the cause of fish consumption advisories in 40 states for inland waters and advisories for some saltwater species in 10 states.(3)There are a number of adverse environmental effects of coal mining and burning, specially in power stations including: Generation of hundreds of millions of tons of waste products, including fly ash, bottom ash, flue gas desulfurization sludge, that contain mercury, uranium, thorium, arsenic, and other heavy metals.(4)Trace elements of uranium. All but 16 of the 92 naturally occurring elements have been detected in coal, mostly as trace elements below 0.1 percent (1,000 parts per million, or ppm). A study by DOE's Oak Ridge National Lab found that radioactive emissions from coal combustion are greater than those from nuclear power production.(5)

We have heard about a fatal accident explosion at a coal mine in central China that killed 26 miners in Dec 08, 2010. They were working despite an order to halt production. And, a mine tunnel collapse elsewhere left four dead in the latest accidents to strike the country’s mining industry.

‘The most economical method of coal extraction from coal seams depends on the depth and quality of the seams, and the geology and environmental factors. Coal mining processes are differentiated by whether they operate on the surface or underground. Many coals extracted from both surface and underground mines require washing in a coal preparation plant.

Technical and economic feasibility are evaluated based on: regional geologic conditions; overburden characteristics; coal seam continuity, thickness, structure, quality, and depth; strength of materials above and below the seam for roof and floor conditions; topography (especially altitude and slope); climate; land ownership as it affects the availability of land for mining and access; surface drainage patterns; ground water conditions; availability of labor and materials; coal purchaser requirements in terms of tonnage, quality, and destination; and capital investment requirements.(6)

Surface mining and deep underground mining are the two basic methods of mining. The choice of mining method depends primarily on depth of burial, density of the overburden and thickness of the coal seam. Seams relatively close to the surface, at depths less than approximately 180 ft (50 m), are usually surface mined. Coal that occurs at depths of 180 to 300 ft (50 to 100 m) are usually deep mined, but in some cases surface mining techniques can be used. For example, some western U.S. coal that occur at depths in excess of 200 ft (60 m) are mined by the open pit methods, due to thickness of the seam 60–90 feet (20–30 m). Coals occurring below 300 ft (100 m) are usually deep mined.(7)

Surface coal mining with valley fills has impaired the aquatic life in numerous streams in the Central Appalachian Mountains. Our results show that mining activity has had subtle to severe impacts on benthic

macroinvertebrate communities and that the biological condition most strongly correlates with a gradient

of ionic strength.(8)

Legal liability

v  Coal transport railway: its construction is subjected to the EIA requirements as classified under activity ‘Railways’ covering a) Construction of new routes and b) Construction of branched lines.

Port facility: its construction is its construction is subjected to the EIA requirements as classified under activity ‘Ports’ covering Construction of ports and Port expansion involving an increase of 50% or more in handling capacity per annum.

‘When coal cargo oxidises, it spontaneously generates heat and toxic gases such as carbon monoxide. This can lead to flammable atmospheres in the hold, depletion of oxygen in those spaces and corrosion of metal structures. Lower quality coals such as lignite are more prone to this process than higher quality coals such as anthracite. Understanding the quality of coal being shipped and how to monitor it is fundamental to reducing the risk of self-heating, and possibly the outbreak of fire.’(9)

‘A Chinese coal-carrier, the Shen Neng 1, loaded with 65,000 tonnes of coal and 975 tonnes of fuel oil, ran aground on the Great Barrier Reef over Easter. The 230-metre ship, on its way from Gladstone to China, strayed from authorised shipping channels into a restricted zone and hit Douglas Shoal, near Rockhampton, at full speed.’(10)

Transporting coal produces significant quantities of air pollution and other environmental problems. Diesel trucks, trains, and barges which transport coal all emit toxic chemicals, such as nitrogen oxide and particulates, which pose serious public health risks. According to a National Resources Defense Council study, railroad engines and trucks hauling coal together release more than 600,000 tons of nitrogen oxide and 50,000 tons of particulate matter into the air every year, mostly in diesel exhaust.(11)

The environmental impact of shipping includes greenhouse gas emissions and oil pollution. Carbon dioxide emissions from shipping is currently estimated at 4 to 5% of the global total, and estimated by the International Maritime Organisation (IMO) to rise by up to 72% by 2020 if no action is taken.(12)

Legal liability

Additionally, it is also worthwhile to check issues pertainning to legal liabilities for any untoward but probable marine accidents or incidents that may cause coal to contaminate marine waters. Marine waters are legally classified into ‘international waters’ or ‘nations’ waters’. In high seas or international waters ship owners or transporters and its underwriters are exposed to the Law of The Sea. When the vessel or barge enters within 200 nautical miles of any states, the Exclusive Economic Zone Act, 1984 is applied. And, as it enters within 12 nautical miles of the state’s lowest tide shore line they are within the state’s full jurisdiction under their respective state’s marine and/or environmental legislation. The contamination of Malaysian marine waters are stipulated under The Environmental Quality Act, 1974 (EQA’74) – Section 27 and 29 for ‘waste, oil and sludge’ which carries a maximum penalty of RM500,000.00 and/or 5 years imprisonment.

Leachate emanating from a coal-storage area at an electricutility plant in Northwest Indiana (U.S.A.) is impacting groundwater quality. This assessment is based on results of a long-term groundwater monitoring program conducted at Purdue University's Wade Utility Plant where a monthly average of 32,000 metric tons of both high- and low-sulfur coal are stored.(13)

By virtue of the fact that coal storage bunkers, piles and warehouses are almost permanent structures, the period of contact or potential contact of coal materials and the soils that support them may extend to a very long duration. The ambient conditions such as humidity, temperature and weather are main factors affecting their mobility into adjacent environmental media. In cases of accidential spillage that would generally occur and affect surfaces of the ground or drainage systems are quite easily apprehendable with quick recovery and cleaning using conventional methods. However, over prolonged storage, spillage and other incidental releases may cause the partly degraded constituents of coal materials to leach into the soil system. These degraded constituents are detached from the pre-crushed coal granules or powder by abiotic factors as mentioned above i.e. ambient conditions and may be in many forms of volatile organic carbons, minerals and metallic compounds. It is an important environmental practice to monitor these movements before it is too late. These ‘fugitive’ contaminants have characters that is reflected if they have entered the soil. Coal can leach into the soil is a fact which is proven by some researchers who performed controlled experiments. ‘Leachates are characterized by low pH (1,67 – 3.22), high conductivity (330 – 24000 umhos) and high concentration of suspended materials (322 – 3300 mg/L)’.(14)  Therefore, these parameters should be a standard indicators to determine the presence of leach that originates from these coal storage areas. Of cause considerations of the soil natural characteristics and environmental qualities must be done in prior as its standard benchmark and presumably reported in their detailed E.I.A report. Hence, periodic bore sampling from groundwater monitoring wells and schematic or random soil grid sampling around a specified perimeter of the storage yard should provide the essential monitoring data for the state of environmental quality of the soils around the coal yard.

Legal liability

Contaminating soils in Malaysia is subjected to Section 24, Environmental Quality Act, 1974 (EQA’74) – which carries a maximum penalty of RM100,000.00 and/or 5 years imprisonment. And, in addition to this the DOE reserves their rights to use other provisions of the same law if the contamination level exceeded its permitted level as approved in the relevant E.I.A.’s terms and conditions of approval as Power generation and transmission projects are subjected to Order-2, Environmental Quality (Prescribed Activities) (Environmental Impact Assessment) Order, 1987

Pulverizer is a mechanical device for the grinding of many different types of materials. Types of Pulverisers: Ball and Tube mills; Ring and Ball mills; MPS; Ball mill; Demolition. Raw material enters the top of the pulverizer through the raw material feed pipe. The raw material is then pulverized between the roll and rotating ring. Hot air is forced in through the bottom of the pulverizing chamber to remove unwanted moisture and transport the material dust up through the top of the pulverizer and out the exhaust pipe directly to the burner. Material that has not been pulverized into fine enough particles cannot be blown out of the top of the unit; it falls back to the ring and roll to be further pulverized.

Environmental Issues

·         Dusts; Although dust sizes are still far larger than 10 um i.e. above 70um, it still pose a threat especially during plant shut-down and start-up. “Major environmental risk in coal pulverizer operation is known to be explosion. The main explosion hazard associated with a pulverizer is related to start-up and shut-down procedures.  When a system goes down under load, all the coal falls out of suspension.  The internal surfaces are at elevated temperatures and the process of spontaneous combustion begins immediately.”(15)

·         Noise; According to a report by SENES Consultants Limited titled NOISE ASSESSMENT STUDY BRANDON GENERATING STATION quoted: “When in operation, the noise from the boiler, coal pulverizers, pumps and fans are the dominant noise sources inside the building, with pulverizers and Station air compressor being the chief sources on the main floor  and the boiler on the higher floors.

·         Vibration; On paper it’s all about observing technical specifications, but, in practice a different ball game comes to play – cost! Maintenance should not be compromised with cost. A report showed that inaccurate parts replacement in pulverizers has led to excessive vibration. “Normal bearing vibration should be less than .10 IPS velocity. Vibration data collection and monitoring was conducted over several days and it was found that the vibration level would change from one startup to the next” .... “used the incorrect bearing outer race measurement”(16)

·         Heat is convected from pipes and metal surfaces that embodied the equipment continuously and dispersed constantly within the process area or building;

Legal Liability: A collective liability based on compliance to specific terms and conditions of the EIA Approval from the DOE. The dust from this equipment may be released from cracked pipes leading to the ESP and enters the Ambient Air as Suspended Particulates.

Dryers: they are used in order to remove the excess moisture from coal which are usually  wetted during transport. As the presence of moisture will result in fall in efficiency due to incomplete combustion and also result in CO emission. The Coal-In-Tube Dryer (CIT) technology  enables operating parameters such as pressure and rotating speed can be automatically determined in response to inlet coal moisture and throughput in order to maintain the desired outlet moisture. Optimum moisture is needed to facilitate a kind of ‘wet oxidation’ that enhance combustibility.

Environmental Issue:

·         ‘Fugitive dust’ that escape through pin-holes or cracks at joints and bends; since the acidic nature, abrasive power and speed is an attrition to metal parts and pipes;

·         Heat is released continuously and dispersed constantly within the process area or building;

·         Solid wastes; are usually broken equipments and parts;

·         Material spillage; spill-over from loose conveyor belts;

·         Oil spillage; from leaking oil sumps, gear-box, pumps, etc.

·         Noise; from conveyors transfer-drops, mechanical moving parts, etc.

Legal Liability

·         ‘Fugitive dust’; are not measurable as ‘point-source’ emission. But, experiences from root-cause-analyses derived from ambient air quality data that showed marked higher readings on Total Suspended Particulates (TSP), have narrowed down to this equipment system as one of the sources.

·         Heat; is not regulated under the EQA’74 for its thermal impact but may be covered in occupational health and safety provisions.

·         Solid wastes; Only when these broken parts are contaminated with lubricating or hydraulic oil or other sheduled waste would they be rendered as scheduled waste: SW 422 - A mixture of scheduled and non-scheduled wastes

·         Material spillage; Coal granules are not subjected to the EQA’74 but if it remained to be evident as contaminating the soil then the operation is liable under Section 24, Environmental Quality Act, 1974 that prohibit soil contamination.

·         Oil spillage; If they are recovered and contained then they are regarded as scheduled waste under SW 408 - Contaminated soil, debris or matter resulting from cleaning-up of a spill of chemical, mineral oil or scheduled wastes, otherwise, the contaminated area shall pose as an evidence of soil contamination and liable to Section 24, Environmental Quality Act, 1974.

Noise; its permitted level shall conform to the limits allowed by the DOE under their EIA Approval terms and conditions as measured usually at the premise’s boundary perimeters.

Magnetic separators: Coal which is brought in may contain contaminants like iron particles. These iron particles may cause unnecessary or premature wear and tear to mechnical parts of subsequent processes. The iron particles may include bolts, nuts wire fish plates etc. So, these undesirable contaminants are removed with the help of  magnetic separators. The ‘cleaner’ coal are transferred to the storage site usually near the boiler.

“A concentrated stream of the inorganic minerals is withdrawn from the pulverizer and processed by the magnetic separator.”(17)

Environmental issue:

v  Dry Magnetic Separator;

Ø  Residues or trapped impurities retained and later released from the separator.

Ø  Dust of fine particles;

Ø  Solid waste of coarse particles and granules.

v  Wet Magnetic Separator;

Ø  Wastewater containing retentate from the separator.

Legal Liability

Ø  ‘Residues or trapped impurities retained and later released from the separator and Solid waste of coarse particles and granules.’ These waste or their final waste considering posibilities of recovery efforts, may subscribe to the Environmental Quality (Scheduled Wastes) Regulations, 2005 under the following possible classification;

§  SW 101                   Waste containing arsenic or its compound; or

§  SW 109                   Waste containing mercury or its compound; or

§  SW 205                   Waste gypsum arising from chemical industry or power plant (need justification);

§  SW 407                   Waste containing dioxins or furans;

§  SW 410                   Rags, plastics, papers or filters contaminated with scheduled wastes;

§  SW 421                   A mixture of scheduled wastes

§  SW 422                   A mixture of scheduled and non-scheduled wastes

Ø  Dust of fine particles are subjected to the law if released prior an air pollution control equipment such as the Filter Bag or Electrostatic Precipitator namely the  Environmental Quality (Clean Air) Regulations, 1978 or other restrictions inposed under their EIA approval’s terms and conditions.

Ø  Wastewater containing retentate from the separator;

§  SW 204       Sludges containing one or several metals including chromium, copper, nickel, zinc, lead, cadmium, aluminium, tin, vanadium and beryllium;

Wastewater are generally subjected to Environmental Quality (Industrial Effluent) Regulations, 2009 or otherwise subjected to other specific requirement by the DOE, including their EIA approval’s terms and conditions.

Environmental issues

§  Dust and other air impurities; are supposed to flow into the receiving air pollution control equipment designed to trap, contain and prevent them from entering the atmosphere. The supposedly ‘cleaner air’ is released out from the stack and shall conform to the emission standard set under Environmental Quality (Clean Air) Regulations, 1978 or, other specific requirement by the DOE, including their EIA approval’s terms and conditions.

§  Fugitive dust and fly-ash; escapes from their respective contained equipment and ductings may enter the surrounding ambience depending on their size, wind velocity and direction and other geo-metereological factors. The Malaysian Interim Ambient Air Guidelines may be applied as a legal directive.

§  Heat; or thermal effect into the surrounding air is affecting surrounding environment but not regulated in the local environmental law. However, heat is known to be conducted through rock structures stretching from beneath the furnace or kiln and causes an impact to vegetation growing immediately above the same seam of rock which are located elsewhere.

§  Solid waste – defected or broken parts; The fact is these parts are usually contaminated with hazardous deposts mentioned earlier, otherwise, it’s worth to recover and recycle these metal wastes

§  Slag deposit; are likely to to subscribe to to the Environmental Quality (Scheduled Wastes) Regulations, 2005

Bottom ash; that consists of an array of toxic and hazardous elements are usually handled via a special Ash Management Program as stipulated under EIA approval’s terms and conditions and may be classified as SW 104 Dust, slag, dross or ash containing arsenic, mercury, lead, cadmium, chromium, nickel, copper, vanadium, beryllium, antimony, tellurium, thallium or selenium excluding slag from iron and steel factory and managed as Scheduled Waste.

Electrostatic precipitation(18) removes particles from the exhaust gas stream of an industrial process. Often the process involves combustion, but it can be any industrial process that would otherwise emit particles to the atmosphere. Six activities typically take place:

v  Ionization - Charging of particles;

v  Migration - Transporting the charged particles to the collecting surfaces; and

v  Collection - Precipitation of the charged particles onto the collecting surfaces; and

v  Charge Dissipation - Neutralizing the charged particles on the collecting surfaces; and

v  Particle Dislodging - Removing the particles from the collecting surface to the hopper; and

v  Particle Removal - Conveying the particles from the hopper to a disposal point.

The major precipitator components that accomplish these activities are as follows: 
§Discharge Electrodes
Power Components
§  Precipitator Controls
§  Rapping Systems
§  Purge Air Systems
§  Flue Gas Conditioning

Environmental Issues:

Ash: collected from the bottom of ESP as trapped ash shall be subjected to specific Ash Management Program approved by the authorities, however, it may be classified as SW 104 Dust, slag, dross or ash containing arsenic, mercury, lead, cadmium, chromium, nickel, copper, vanadium, beryllium, antimony, tellurium, thallium or selenium excluding slag from iron and steel factory as Scheduled Waste.

Stack Emission: is subjected to emission standard under the Environmental Quality (Clean Air) Regulations, 1978 and other legal biding specification listed in the EIA approval’s terms and conditions.

Risk of fire or explosion exists in several electrostatic precipitators, mainly because of the production of CO.(19)

Environmental issue:

Water is an invaluable environmental resource. The balance between its intake for use in powerplant and the natural capacity of the biosphere to replenish this sudden extraction from its reservoir is a concern. The ‘lost of arable land’ due to aggresive development where land surfaces have been replaced by cemented structures and tarmacs have reduced the replenishment of water once held by the subsurface as ground waters or aquifers, apart from causing inundation in other areas. The nature do interact to our act!

·       Power generation has been estimated to be second only to agriculture in being the largest domestic user of water.

·       The U.S. Geological Survey estimates that thermoelectric plants withdrew 195 billion gallons of water per day in 2000, of which 136 billion gallons was fresh water.(20)

General numbers for fresh water usage of different power sources are shown below.(21)

	Water usage (gal/MW-h)
Power source	Low case	Medium/Average case	High case
Nuclear power	400 (once-through cooling)	400 to 720 (pond cooling)	720 (cooling towers)
Coal	300		480
Natural gas	100 (once-through cycle)		180 (with cooling towers)
Hydroelectricity		1,430
Solar thermal		1,060
Geothermal	1,800		4,000
Biomass	300		480
Solar photovoltaic		30
Wind power	.5	1	2.2

·       To produce and burn the 1 billion tons of coal America uses each year, the mining and utility industries withdraw 55 trillion to 75 trillion gallons of water annually, according to the US Geological Survey.

Researchers at Sandia National Laboratories put the estimate higher, finding that the typical 500-megawatt coal-fired utility burns 250 tons of coal per hour, using 12 million gallons of water an hour - 300 million gallons a day - for cooling.(22)

Steam turbines have been used predominantly as prime mover in all thermal power stations. The steam turbines are mainly divided into two groups: -

1.       Impulse turbine

2.       Impulse-reaction turbine

The turbine generator consists of a series of steam turbines  interconnected to each other and a generator on a

common shaft.  There is a high pressure turbine at one end, followed by an intermediate pressure turbine, two low pressure turbines, and the generator. The steam at high temperature (536 ‘c to 540 ‘c) and pressure (140 to 170 kg/cm²) is expanded in the turbine. Steam turbines can be a very reliable equipment with life over 30 years and overhaul approximately every 10 years. However, about 5 percent of the indsutrial and utility turbines experience corrosion and deposition problem. Mostly due to LP blade and blade attachment (disc rim) corrosion fatigue or stress corrosion failures. (23) 

Environmental issues:

v  Spent or Used Hydraulic Fluid; are subjected to legal requirements under Environmental Quality (Scheduled Wastes) Regulations, 2005 - SW 306  Spent hydraulic oil

v  Broken Oil Seals and Caskets, including hydraulic fluid pumps, hydraulic actuators, as well as the solenoids, and servo valves, etc.; are subjected to legal requirements under Environmental Quality (Scheduled Wastes) Regulations, 2005 - SW 422 A mixture of scheduled and non-scheduled wastes

v  Scales and varnish-like deposits; a compositional and TCLP analysis is recommended prior arriving to a legal conclusion – the result is useful to determine if its classification is (SW 204 - Sludges containing one or several metals including chromium, copper, nickel, zinc, lead, cadmium, aluminium, tin, vanadium and beryllium) or (SW 205 - Waste gypsum arising from chemical industry or power plant)

v  Used Oil Filters; are subjected to legal requirements under Environmental Quality (Scheduled Wastes) Regulations, 2005 - SW 410 Rags, plastics, papers or filters contaminated with scheduled wastes.

v  Contaminated Gloves & Rags;  are subjected to legal requirements under Environmental Quality (Scheduled Wastes) Regulations, 2005 - SW 410 Rags, plastics, papers or filters contaminated with scheduled wastes.

v  Broken Metal Blades and other Metal Parts; these engineered high quality metal parts may be repaired or disposed in most economic manner.

v  Rust Dust; Despite its associated potential risk to human health, these dust are scattered around the working area and difficult to collect and contain. In practice mass cleaning using wet-jet or vacuum machine cleaners are being done and regarded as ‘normal’ utility waste.

Legal Liability

The Scheduled Waste Management carries a maximum penalty of RM500,000.00 and/or 5 years in cases when the scheduled waste (SW) are transported by non-DOE-approved SW contractors to destination, facilities or premises not authorized/licensed to receive, store, transit, treat or dispose them.

Generator or Alternator is the electrical end of a turbo-generator set. It is generally known as the piece of equipment that converts the mechanical energy of turbine into electricity. The generation of electricity is based on the principle of electromagnetic induction.

Environmental issue:

v  Noise; its permitted level shall conform to the limits allowed by the DOE under their EIA Approval terms and conditions or the overall power plant’s blanket approval. In many instances a doule standard for the day and night is imposed. The approval may specify the number of noise level parameters, monitoring points, sampling frequency and its general location. However, the exact location of these monitoring points should be based on a throrough ‘Noise-Mapping’ survey with adequate rationalization based on environmental receptors fully illustrated in a layout plan and be submitted to the agency for record.

v  Vibration; Despite the absence of specific vibration monitoring parameters and limits as legal requirement in the EQA’74, the DOE may opt to adapt foreign standards or guidelines to monitor this element of environmental impact.

v  Cooling fluid; Generally, if the type of cooling fluid is the oil-water emulsion then their waste forms are subjected to legal requirements under Environmental Quality (Scheduled Wastes) Regulations, 2005 – SW 307 Spent mineral oil-water emulsion or, if they are specific thermal coolants as in conventional radiators; - SW 327 Waste of thermal fluids (heat transfer) such as ethylene glycol, otherwise in some cases where the hydraulic fluid acts as coolant; - SW 306 Spent hydraulic oil. So, a proper identification of the types and nature is crucial prior notification to the DOE.

v  Broken parts: If any generator in power plants is regarded by the DOE as and electrical-electronic based equipment, its waste/used electrical parts may be classified as SW 110 - Waste from electrical and electronic assemblies containing components such as accumulators, mercury-switches, glass from cathode-ray tubes and other activated glass or polychlorinated biphenyl-capacitors, or contaminated with cadmium, mercury, lead, nickel, chromium, copper, lithium, silver, manganese or polychlorinated biphenyl. Otherwise, most of the metal waste may be more economic for disposal to conventional metal recyclers.

Legal Liability

v  Noise emission – contravention may be regarded as non-compliance to EIA’s terms and conditions of approval or the ‘blanket’ approval and may be charged under Section 41 of The EQA’74 with a maximum liability of RM10,000.00 and/or 2 years imprisonment. Note: Section 23 on noise pollution is not meant for power plants or other industrial sources.

The Scheduled Waste Management carries a maximum penalty of RM500,000.00 and/or 5 years in cases when the scheduled waste (SW) are transported by non-DOE-approved SW contractors to destination, facilities or premises not authorized/licensed to receive, store, transit, treat or dispose them.

Environmental Issues

Fly ash is generally captured by electrostatic precipitators or other particle filtration equipment before the flue gases reach the chimneys of coal-fired power plants, and together with bottom ash removed from the bottom of the furnace is in this case jointly known as coal ash. Depending upon the source and makeup of the coal being burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts of silicon dioxide (SiO2) (both amorphous and crystalline) and calcium oxide (CaO), both being endemic ingredients in many coal-bearing rock strata.(24)

Flue Gas Desulfurization (FGD) gypsum is also known as scrubber gypsum. FGD gypsum is the byproduct of an air pollution control system that removes sulfur from the flue gas in calcium-based scrubbing systems. It is produced by employing forced oxidation in the scrubber and is composed mostly of calcium sulfate.(25) However, this waste much sought after by the cement manufacturing industry. Thus, through a provision called ‘Special Management of Scheduled Waste’ this waste may have an extended life-cycle as building materials.

Toxic constituents depend upon the specific coal bed makeup, but may include one or more of the following elements or substances in quantities from trace amounts to several percent:  arsenic,  beryllium,  boron,  cadmium,  chromium, chromium VI,  cobalt,  lead,  manganese,  mercury,  molybdenum, selenium,  strontium,  thallium, and vanadium, along with  dioxins and PAH compounds.(26)

A 2007 study by the U.S. Environmental Protection Agency showed more than 60 sites nationwide where coal ash is suspected or has been proven to have polluted water. Selenium, a byproduct of the coal processing that can cause fish and bird deformities, was implicated at more than 20 of the sites, including Belews Lake in North Carolina — a cooling lake for another Duke Energy power plant.(27)

  

Legal Liability

v  Effluent from Wastewater Treatment Plant or IETS: Prior entering the Ash Pond wastewater from the facility including surface run-offs are in many cases channeled into the IETS for treatment aimed not only to remove suspended ash-dust solids but also trace inorganics such as heavy metals and their compounds. The final discharge is required to comply to any specification laid under their EIA’s Approval Terms and Conditions and/or the Environmental Quality (Industrial Effluent) Regulations, 2009. Contravening the later is subjected to a maximum liability of RM100,000.00 and/or 5 years imprisonment.

v  Sludge from IETS: is very likely a Scheduled Waste thus rendering it to subscribe to Environmental Quality (Scheduled Wastes) Regulations, 2005 – SW 427 Mineral sludges including calcium hydroxide sludges, phosphating sludges, calcium sulphite sludges and carbonates sludges

v  FGD gypsum: is a Scheduled Waste thus rendering it to subscribe to Environmental Quality (Scheduled Wastes) Regulations, 2005 - SW 205 Waste gypsum arising from chemical industry or power plant.

v  Ash Pond Overflow discharges: In some recent examples it is noted that the treated discharges from the Ash Pond is being reused into the power plant’s facility and its a noteworthy environmental endeavor. Nonetheless, its discharges into the receiving water body shall conform to Environmental Quality (Industrial Effluent) Regulations, 2009. 

Seepage from Ash Pond: Although in the construction of recent Ash Ponds certain types of ‘non-pemeable’ layers of materials were deployed, it is still unclear of it’s permeable-proof qualities. Geo-textiles are not absolutely permeable-proof though.

It is understandable that energy is a basic need of modern life and that power generation plants have ‘lit’ our daily and nightly lives. Besides power plants are our other activities that are equally responsible in ‘shaping’ the ‘quality’ of life. In other words, everything humans do, including what NGOs are doing too, are polluting the environment. The issue of debate and dispute then narrows down to ‘how much and how long’. There is no absolute solution to pollution. As we think into it, we’d realise that all these so called ‘pollution prevention and control’ efforts simply transform and transfer them. Thus, it is important to note that whatever we ‘dump’ into the environment are coming back, not in the form that we dump, but, in the form of our favourite dish! Biological magnification often refers to the process whereby certain substances such as pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. The substances become concentrated in tissues or internal organs as they move up the chain. Bioaccumulants are substances that increase in concentration in living organisms as they take in contaminated air, water, or food because the substances are very slowly metabolized or excreted. Although sometimes used interchangeably with 'bioaccumulation,' an important distinction is drawn between the two, and with bioconcentration, it is also important to distinct between sustainable development and overexploitation in biomagnification.

§  Bioaccumulation occurs within a trophic level, and is the increase in concentration of a substance in certain tissues of organisms' bodies due to absorption from food and the environment.

§  Bioconcentration is defined as occurring when uptake from the water is greater than excretion.

Thus bioconcentration and bioaccumulation occur within an organism, and biomagnification occurs across trophic (food chain) levels. Biodilution is also a process that occurs to all trophic levels in an aquatic environment; it is the opposite of biomagnification, thus a pollutant gets smaller in concentration as it progresses up a food web.(28)

KUALA LUMPUR: Malaysia will become a net energy importer before 2020 and is therefore committed to find alternative means, Deputy Science, Technology and Innovation Minister Fadillah Yusof said Tuesday.(29)

Environmentalists and alternative energy producers have criticised the approval for Malaysia’s first nuclear power plant saying it was rushed through without adequate public consultation given the risks of radioactivity.(30)

The Ninth Malaysian Plan (2006-2010) targets 350 MW of grid-connected renewable electricity by with fuel mix of 40 percent gas, 40 percent coal, 10 percent hydropower and 10 percent renewable energy. Another major development in the offing is the proposed introduction of feed-in-tariff for renewable energy in 2011.(31)

FWEPS (Float Wave Electric Power Station) is one of the promising devices for offshore wave energy conversion which is being developed. The second technique is the electrolytic installation intended for hydrogen production by means of sea water electrolysis followed by usage this ecologically safe fuel in different branches of economy.(32)

In some ways wind power has advantages over solar photovoltaic generation. Wind blows day or night, sunny or cloudy, and often it can be at its strongest potential during the coldest and darkest nights of the winter when it is needed the most. Wind is created when the sun heats certain areas of the Earth's surface more than others. This is called differential heating, and it induced both vertical and horizontal air currents. The patterns of these currents are modified by the Earth's rotation and the contours of the land. Wind is captured and converted into energy with the use of a wind turbine such as the one shown in the diagram. As the wind passes the blades of the tower the rotor will be forced to turn. It is this motion that will turn a generator, thus producing electricity.(33)

Conclusion

There are numerous damaging environmental impacts of coal that occur through its mining, preparation, combustion, waste storage, and transport as summarized as follows:

§  Acid mine drainage (AMD) refers to the outflow of acidic water from coal mines or metal mines, often abandoned mines where ore- or coal mining activities have exposed rocks containing the sulphur-bearing mineral pyrite. Pyrite reacts with air and water to form sulphuric acid and dissolved iron, and as water washes through mines, this compound forms a dilute acid, which can wash into nearby rivers and streams.

§  Air pollution from coal-fired power plants includes sulfur dioxide, nitrogen oxides, particulate matter (PM), and heavy metals, leading to smog, acid rain, toxins in the environment, and numerous respiratory, cardiovascular, and cerebrovascular effects.

§  Air pollution from coal mines is mainly due to emissions of particulate matter and gases including methane (CH4), sulfur dioxide (SO2), and nitrogen oxides(NOx), as well as carbon monoxide (CO).

§  Climate impacts of coal plants - Coal-fired power plants are responsible for one-third of America’s carbon dioxide (CO2) emissions, making coal a huge contributor to global warming. Black carbonresulting from incomplete combustion is an additional contributor to climate change.

§  Coal dust stirred up during the mining process, as well as released during coal transport, which can cause severe and potentially deadly respiratory problems.

§  Coal fires occur in both abandoned coal mines and coal waste piles. Internationally, thousands of underground coal fires are burning now. Global coal fire emissions are estimated to include 40 tons ofmercury going into the atmosphere annually, and three percent of the world's annual carbon dioxide emissions.

§  Coal combustion waste is the nation's second largest waste stream after municipal solid waste. It is disposed of in landfills or "surface impoundments," which are lined with compacted clay soil, a plastic sheet, or both. As rain filters through the toxic ash pits year after year, the toxic metals are leached out into the local environment.

§  Coal sludge, also known as slurry, is the liquid coal waste generated by washing coal. It is typically disposed of at impoundments located near coal mines, but in some cases it is directly injected into abandoned underground mines. Since coal sludge contains toxins, leaks or spills can endanger underground and surface waters.

§  Floods such as the Buffalo Creek Flood caused by mountaintop removal mining and failures of coal mine impoundments.

§  Forest destruction caused by mountaintop removal mining - According to a 2010 study, mountaintop removal mining has destroyed 6.8% of Appalachia's forests.

§  Greenhouse gas emissions caused by surface mining - According to a 2010 study, mountaintop removal mining releases large amounts of carbon through clearcutting and burning of trees and through releases of carbon in soil brought to the surface by mining operations. These greenhouse gas emissions amount to at least 7% of conventional power plant emissions.

§  Loss or degradation of groundwater - Since coal seams are often serve as underground aquifers, removal of coal beds may result in drastic changes in hydrology after mining has been completed.

§  Radical disturbance of 8.4 million acres of farmland, rangeland, and forests, most of which has not been reclaimed -- See The footprint of coal

§  Heavy metals and coal - Coal contains many heavy metals, as it is created through compressed organic matter containing virtually every element in the periodic table - mainly carbon, but also heavy metals. The heavy metal content of coal varies by coal seam and geographic region. Small amounts of heavy metals can be necessary for health, but too much may cause acute or chronic toxicity (poisoning). Many of the heavy metals released in the mining and burning of coal are environmentally and biologically toxic elements, such as lead, mercury, nickel, tin, cadmium, antimony, andarsenic, as well as radio isotopes of thorium and strontium.

§  Mercury and coal - Emissions from coal-fired power plants are the largest source of mercury in the United States, accounting for about 41 percent (48 tons in 1999) of industrial releases.

§  Methane released by coal mining accounts for about 10 percent of US releases of methane (CH₄), a potent global warming gas.

§  Mountaintop removal mining and other forms of surface mining can lead to the drastic alteration of landscapes, destruction of habitat, damages to water supplies, and air pollution. Not all of these effects can be adequately addressed through coal mine reclamation.

§  Particulates and coal - Particulate matter (PM) includes the tiny particles of fly ash and dust that are expelled from coal-burning power plants. Studies have shown that exposure to particulate matter is related to an increase of respiratory and cardiac mortality.

§  Radioactivity and coal - Coal contains minor amounts of the radioactive elements, uranium and thorium. When coal is burned, the fly ash contains uranium and thorium "at up to 10 times their original levels."

§  Subsidence - Land subsidence may occur after any type of underground mining, but it is particularly common in the case of longwall mining.

§  Sulfur dioxide and coal - Coal-fired power plants are the largest human-caused source of sulfur dioxide, a pollutant gas that contributes to the production of acid rain and causes significant health problems. Coal naturally contains sulfur, and when coal is burned, the sulfur combines with oxygen to form sulfur oxides.

§  Thermal pollution from coal plants is the degradation of water quality by power plants and industrial manufacturers - when water used as a coolant is returned to the natural environment at a higher temperature, the change in temperature impacts organisms by decreasing oxygen supply, and affecting ecosystem composition.

§  Toxins - According to a July 2011 NRDC report, "How Power Plants Contaminate Our Air and States"  electricity generation in the U.S. releases 381,740,601 lbs. of toxic air pollution annually, or 49% of total national emissions, based on data from the EPA’s Toxic Release Inventory (2009 data, accessed June 2011). Power plants are the leading sources of toxic air pollution in all but four of the top 20 states by electric sector emissions.

§  Transportation - Coal is often transported via trucks, railroads, and large cargo ships, which release air pollution such as soot and can lead to disasters that ruin the environment, such as the Shen Neng 1 coal carrier collision with the Great Barrier Reef, Australia that occurred in April 2010.

§  Waste coal, also known as "culm," "gob," or "boney," is made up of unused coal mixed with soil and rock from previous mining operations. Runoff from waste coal sites can pollute local water supplies.^[28]

§  Water consumption from coal plants - Power generation has been estimated to be second only to agriculture in being the largest domestic user of water.

§  Water pollution from coal includes the negative health and environmental effects from the mining, processing, burning, and waste storage of coal.

 (Source: http://www.sourcewatch.org/index.php?title=Environmental_impacts_of_coal)

Relevant Data from Wikipedia: http://en.wikipedia.org/wiki/Coal

Energy density

Main article: Energy value of coal

The energy density of coal, i.e. its heating value, is roughly 24 megajoules per kilogram.^[59]

The energy density of coal can also be expressed in kilowatt-hours, the units that electricity is most commonly sold in, per units of mass to estimate how much coal is required to power electrical appliances. One kilowatt-hour is 3.6 MJ, so the energy density of coal is 6.67 kW·h/kg. The typical thermodynamic efficiency of coal power plants is about 30%, so of the 6.67 kW·h of energy per kilogram of coal, 30% of that—2.0 kW·h/kg—can successfully be turned into electricity; the rest is waste heat. So coal power plants obtain approximately 2.0 kW·h per kilogram of burned coal.

As an example, running one 100-watt lightbulb for one year requires 876 kW·h (100 W × 24 h/day × 365 day/year = 876000 W·h = 876 kW·h). Converting this power usage into physical coal consumption:

For a coal power plant with a 40% efficiency, it takes 325 kg (714 lb) of coal to power a 100 W lightbulb for one year.^[60] One should also take into account transmission and distribution losses caused by resistance and heating in the power lines, which is in the order of 5–10%, depending on distance from the power station and other factors.

Carbon intensity

Commercial coal has a carbon content of at least 70%. Coal with a heating value of 6.67 kWh per kilogram as quoted above has a carbon content of roughly 80%, which is

 , where 1 mol equals to N_A (Avogadro Number) atoms.

Carbon combines with oxygen in the atmosphere during combustion, producing carbon dioxide, with an atomic weight of (12 + 16 × 2 = 44 kg/kmol). The CO₂ released to air for each kilogram of incinerated coal is therefore

.

This can be used to calculate an emission factor for CO₂ from the use of coal power. Since the useful energy output of coal is about 31% of the 6.67 kWh/kg(coal),^[61] the burning of 1 kg of coal produces about 2 kWh of electrical energy. Since 1 kg coal emits 2.93 kg CO₂, the direct CO₂ emissions from coal power are 1.47 kg/kWh, or about 0.407 kg/MJ.

The U.S. Energy Information Agency's 1999 report on CO₂ emissions for energy generation,^[62] quotes a lower emission factor of 0.963 kg CO₂/kWh for coal power. The same source gives a factor for oil power in the U.S. of 0.881 kg CO₂/kWh, while natural gas has 0.569 kg CO₂/kWh. Estimates for specific emission from nuclear power, hydro, and wind energy vary, but are about 100 times lower.

 References;

1)         (http://www.themalaysianinsider.com)

2)         (http://en.wikipedia.org/wiki/Environmental_impact_of_the_coal industry)

3)         (http://www.epa.gov/ost/fish)

4)         (http://www.censin.com/coal-mining-environmental-effects)

5)         http://www.ucsusa.org

6)         "Methods of Coal Mining"  Great Mining (2003) accessed 19 December 2011

7)         Christman, R.C., J. Haslbeck, B. Sedlik, W. Murray, and W. Wilson. 1980. Activities, effects and impacts of the coal fuel cycle for a 1,000-MWe electric power generating plant. Washington, DC: U.S. Nuclear Regulatory Commission.

8)         Gregory J. Pond et.al., “Downstream effects of mountaintop coal mining: comparing biological conditions using family- and genus-level macroinvertebrate bioassessment tools”, Region 3, US Environmental Protection Agency

9)         http://marine-cafe.com

10)     http://education.theage.com.au;April 27, 2010

11)     http://www.worc.org/userfiles/file/Coal/Exporting_Powder_River_Basin_Coal_Risks_and_Cost.pdf

12)     CO₂ output from shipping twice as much as airlines - The Guardian

13)     Angie M. Cook and Steven J. Fritz “Environmental Impacts of Acid Leachate Derived from Coal-Storage Piles upon Groundwater”

14)     Ferdinger et.al “Characterization of Organic Material Leached from Coal by Simulated Rainfall”, in Environmental Science and Technology, 1989, 23, 170-177

15)     CLETE R. STEPHAN, P.E.MINE, ‘COAL DUST EXPLOSION HAZARDS’ SAFETY AND HEALTH ADMININSTRATION PITTSBURGH, PENNSYLVANIA, p.8, year – unknown, p.8

16)     http://www.reliableplant.com

17)     http://magneticseparation.com

18)     http://www.neundorfer.com/knowledge_base/electrostatic_precipitators.aspx

19)     István Kiss,  Tamás Iváncsy,  Bálint Németh,  István Berta, ‘Advanced Risk Analysis for the Application of ESP-s to Clean Flammable Gas-pollutant Mixtures’, in 11th International Conference on Electrostatic Precipitation, pp.50

20)     Lance Frazer, "Low water consumption: a new goal for coal" in Environmental Health Perspectives, April, 2004

21)     http://en.wikipedia.org/wiki/Environmental_impact_of_electricity_generation

22)     Sierra Crane-Murdoch, "A Desperate Clinch: Coal Production Confronts Water Scarcity" Circle of Blue, August 3, 2010

23)     Otakar Jones & Lee Machemar, ‘Steam Turbines Corrosion and Deposition Problem and Solutions; turbolab.tamu.edu

24)     Source: http://en.wikipedia.org

25)     http://instrumentations.blogspot.com

26)     Source: Managing Coal Combustion Residues in Mines, Committee on Mine Placement of Coal Combustion Wastes, National Research Council of the National Academies, 2006; and Human and Ecological Risk Assessment of Coal Combustion Wastes, RTI, Research Triangle Park, August 6, 2007, prepared for the U.S. Environmental Protection Agency

27)     Source: http://www.usatoday.com/news/nation/2009-02-26-ashponds

28)     http://en.wikipedia.org/wiki/Biomagnification

29)     http://biz.thestar.com.my/news/story.asp?sec=business&file=/2010/4/27

30)     http://www.themalaysianinsider.com/malaysia/article/nuke-plant-jolts-environmentalists(May 5, 2010)

31)     http://rulemysilentworld.blogspot.com/2011_06_01_archive.html

32)     http://atecom.ru/power-industrial-system

33)     http://www.rowan.edu/colleges/engineering/clinics/cleanenergy

34)   http://www.ikonet.com/en/visualdictionary/static/us/mountains

Author: Khalid Mohd Ariff, 19th March 2012

Reach for the writer Khalid Mohd Ariff

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