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1、 OPTIONS FOR COAL-FIRED POWER PLANTS IN ONTARIO J.T.ROGERS,PhD Professor-Emeritus Department of Mechanical and Aerospace Engineering Carleton University Ottawa,Ontario September 27,2004 TABLE OF CONTENTS 1.0 INTRODUCTION 1 2.0 COAL-FIRED POWER PLANTS IN ONTARIO 1 2.1 Ontario Power Plants and Air Pol
2、lution 1 2.2 Emissions of Air Pollutants 2 2.3 Possible Options to Reduce Air Pollution from Coal-Fired Plants 3 3.0 IMPROVEMENT OF EMISSION CONTROLS AT COAL-FIRED POWER PLANTS 4 4.0 REPLACEMENT OF COAL-FIRED GENERATION BY NATURAL GAS GENERATION 7 4.1 Current Commitments and Plans 7 4.2 Ontario Mini
3、stry of Energy Initiative 8 4.3 Conversion of Coal-Fired Plants to Natural Gas 9 4.4 Natural Gas Availability and Cost Issues 10 4.4.1 Natural Gas Availability 10 4.4.2 Natural Gas Costs 13 5.0 REPLACEMENT OF COAL-FIRED GENERATION BY NEW RENEWABLE(ALTERNATIVE)ENERGY SOURCES 13 5.1 Current Situation
4、13 5.2 Inherent Weaknesses of Alternative Energy Sources for Large-Scale Power Generation 14 5.3 The Economics of Wind Energy 16 5.4 Wind Energy and the Environment 17 6.0 REPLACEMENT OF COAL-FIRED GENERATION BY INCREASED IMPORTATION OF ELECTRICITY TO ONTARIO 18 7.0 REPLACEMENT OF COAL-FIRED GENERAT
5、ION BY NUCLEAR GENERATION 19 7.1 Recent Additions to In-Service Nuclear Capacity 19 7.2 Committed and Potential Additions to Nuclear Capacity 19 7.3 Limitations of Nuclear Generation in Replacing Coal-Fired Generation 20 7.4 Future Need for Nuclear Generation in Ontario 21 8.0 CONCLUSIONS 22 8.1 Act
6、ual and Committed Additions to Ontario Inter-mediate Load Capacity,2003-2009 22 8.2 Improvement of Emission Controls at Coal-Fired Power Plants 23 8.3 Replacement of Coal-Fired Generation by Natural Gas-Fired Generation 24 8.4 Replacement of Coal-Fired Generation by Renewable(Alternative)Energy Sour
7、ces 24 8.5 Replacement of Coal-Fired Generation by Increased Importation of Electricity to Ontario 25 8.6 Replacement of Coal-Fired Generation by Nuclear Generation 25 REFERENCES 27 OPTIONS FOR COAL-FIRED POWER PLANTS IN ONTARIO J.T.ROGERS,PhD Professor-Emeritus Dept.of Mechanical and Aerospace Engi
8、neering Carleton University Ottawa,Ontario 1.0 INTRODUCTION The Ontario Government has announced its intention to phase out the burning of coal for electricity production in Ontario by 2007 because of the resulting air pollution 1.Coal-fired power plants,with an installed capacity of 7578 MW,supplie
9、d 36.2 TWh of electricity in 2003 2,about 23%of Ontarios electricity 1.Therefore,the expressed intention of the Government presents a major challenge-to avoid an electricity supply shortfall caused by taking the coal-fired power plants out of service.The challenge includes not only the replacement o
10、f the coal-fired plants but the accommodation of the forecast increase in electricity demand in Ontario of almost 9%,on a median-growth basis,from 155.1 TWh in 2003 to 168.9 TWh in 2014 and a growth in peak demand,the key to capacity needs,of about 10%,from about 24,100 MW to about 26,600 MW,over th
11、e same period 3.The purpose of this paper is to consider options to meet this challenge.It is well beyond the scope of this paper to undertake an economic analysis of these options,but the need to take into account cost-benefit assessments in evaluating options is emphasized.2.0 COAL-FIRED POWER PLA
12、NTS IN ONTARIO 2.1 Ontario Power Plants and Air Pollution There are five coal-fired power plants in Ontario,as shown in Table 1,which gives data for 2003 2,all operated by Ontario Power Generation(OPG).These plants are significant contributors to air pollution in Ontario,as discussed below in sectio
13、n 2.2.OPG also operates a large fossil-fuel plant,Lennox,which uses both oil and natural gas to generate electricity.As shown in Table 1,this plant typically generates only about 7%of the total OPG fossil fuel plant electricity generated in Ontario 2,4,so that its contribution to air pollution is re
14、latively minor,especially when burning natural gas which is used for about 70%of its generation.Electricity generated in nuclear(40%in 2003 1)and hydro(22%in 2003 1)plants in Ontario produces essentially no air pollution.A small percentage of electricity in Ontario is generated by Independent Power
15、Producers(IPP)and by certain industries using natural-gas fired plants,small hydro plants and waste-fired(e.g.,pulp waste)plants 4,making a minor contribution to air pollution in the province.The annual capacity factors(ACF)for 2003 for the coal-fired plants given in Table 1 indicate that these plan
16、ts are used mainly for intermediate-load service1.Nevertheless,some of these plants,particularly Nanticoke and Lambton,have been used in recent years partly in base-load service to compensate for the loss of base-load capacity resulting from the lay-up for refurbishment of the Pickering-A and Bruce-
17、A nuclear units 4.With the return to service of Bruce units 3 and 4 and Pickering unit 4 in 2003 and the recently announced intention of OPG to refurbish and return to service Pickering unit 1,as recommended by the OPG Review Committee 5,the need for the coal-plants to act as base-load plants will b
18、e reduced,thus reducing emissions of air pollutants.The Lakeview plant,scheduled for shutdown in 2005,now plays an important role because of its proximity to Toronto by supporting system reliability and providing reactive support to maintain local voltages 4.The Thunder Bay and Atikokan plants provi
19、de local generation in Northern Ontario for voltage support and transmission security 4.See reference 6 for a discussion of the need to maintain voltage support in transmission systems.TABLE 1 ONTARIO POWER GENERATION FOSSIL FUEL POWER PLANTS Data for 2003 2 ACF:Annual Capacity Factor,%Station Fuel
20、No.of Units Capacity,MW Energy,TWh ACF,2003 Dates In Service Original Retirement Date Nanticoke Coal 8 3938 20.4 59.1 1973/1978 2015 Lambton Coal 4 1975 10.6 61.2 1969/1970 2010-2020 Lakeview Coal 4 1140 2.8 28.0 1962/1969 2005 Thunder Bay Coal 2 310 1.5 55.2 1981/1982 2021 Atikokan Coal 1 215 0.9 4
21、7.8 1985 2025 TOTAL Coal 19 7578 36.2 54.3 Lennox Oil/Gas 4 2140 2.8 14.9 1976/1977 2016 2.2 Emissions of Air Pollutants The key air pollutants in Ontario are nitrogen oxides(NOx),sulfur dioxide(SO2),fine(respirable)particulate matter,PM,volatile organic compounds(VOC),carbon monoxide and mercury 7,
22、8.Both NOx and VOC lead to the formation of ozone,one major component of smog,while particulate matter is the other major component.Smog and SO2 can irritate the lungs and lower ones resistance to respiratory infection as well as aggravating cardio-vascular 1 Base Load:capacity required to meet rela
23、tively constant demand,i.e.the minimum demand on a utility.Peak Load:capacity required to meet intermittent high demands.Intermediate Load:capacity required above base but below peak demands,e.g.,capacity needed during the day,but not at night,or during the week,but not on weekends.disease.Mercury c
24、an cause cancer and reproductive and developmental effects;the main concern with mercury is that it can accumulate in the food chain,causing exposures significantly higher than those directly from the air 8.The main source of carbon monoxide,which is fatal in high concentrations,is incomplete combus
25、tion in vehicles and other transportation sources 8.The Ontario Medical Association(OMA)has estimated that approximately 1,900 premature deaths in the year 2000 may be attributed to the effects of air pollution in Ontario.Also,the OMA has estimated that,annually,about 9,800 people are admitted to ho
26、spital and some 13,000 people make emergency room visits due to the effects of air pollution in Ontario 7.In addition to negative health effects,NOx and SO2 cause acid rain which can damage lakes,vegetation and structures 8.Of the total production of the most significant of these air pollutants in O
27、ntario in 2000,OPG fossil-fuel power plants produced about 14.7%of the NOx,23.7%of the SO2,22.6%of the mercury and essentially none of the VOC and carbon monoxide 8.(Information on the percentage of fine particulate matter produced from fossil-fuel power plants in Ontario is not provided in referenc
28、e 8)Thus,phasing out of the coal-fired power plants will certainly not eliminate these air pollutants in Ontario,particularly since about 50%of air pollution in Ontario comes from sources in the US mid-west,including coal-fired plants which contribute a much larger percentage of electricity in that
29、region than coal-fired plants do in Ontario 7,8.This fact should be taken into account in examining options for the coal-fired plants in Ontario.The issue of the emission of CO2,a greenhouse gas,from the coal-fired plants is not addressed in this paper,since CO2,as a natural constituent of the atmos
30、phere,does not contribute to the negative health effects of the emissions which are the primary cause of the decision to shutdown the coal-fired plants.2.3 Possible Options to Reduce Air Pollution from Coal-Fired Plants As pointed out in section 1.0,simply shutting down the coal-fired plants in Onta
31、rio by 2007 to reduce air pollution without taking any other action is not really an acceptable option.Nevertheless,there are a number of options that could reduce air pollution from coal-fired power plants in Ontario.These options comprise:Improve emission controls in the coal-fired plants,Convert
32、the coal-fired plants to burn natural gas or build new gas-fired plants to replace the coal-fired plants,Replace at least some of the coal-fired generation by new renewable(alternative)energy sources,Reduce need for the coal-fired plants by greater importation of electricity,Replace the coal-fired p
33、lants by nuclear plants.It should be recognized that the Manley Report 5,suggested that the Ontario government should consider improving emission controls on some of the coal-fired plants and converting others to gas firing as options to shutting them down.However,the Report did not make a recommend
34、ation to this effect.Conservation,including the use of more efficient electrical systems and appliances,the adoption of time-of-use metering 3 and what is more properly termed improvement in the effectiveness of energy use 9,can delay the need for adding additional capacity by reducing the growth of
35、 electricity demand with any of these options.However,the 10-year forecast by the Independent Electricity Market Operator(IMO)already takes into account the effects of projected conservation,based on recent and proposed actions,on the growth rate of electricity demand in Ontario 3.Thus,conservation
36、alone is not really a separate option for reduction of air pollution from coal-fired plants in Ontario,although it will assist all of the options by reducing demand to some extent.See section 4.0 for a discussion of an initiative of the Ontario Ministry of Energy in this area.In assessing these opti
37、ons,their costs of implementation and other factors should be taken into account as well as their benefits in the reduction of adverse health effects.An effective approach for doing so is the application of the ALARA and“De Minimis”principles as applied in the regulation of nuclear activities in Can
38、ada and elsewhere 10,11.The ALARA(As Low as Reasonably Achievable)principle means that economic and social factors are to be taken into account in setting limits for risk or exposure to adverse health effects on a societal basis,while ensuring that individuals are protected by specific legal require
39、ments.The“De Minimis”principle states that risks of an activity need not be reduced below a level that is generally accepted as being of no significance to an individual or to a society.That is,risks need not be reduced below a level at which efforts to control the sources of risks would constitute
40、an undue expenditure of societal resources for an insignificant benefit in health protection.The following sections discuss the above-listed options and draw certain conclusions.3.0 IMPROVEMENT OF EMISSION CONTROLS AT COAL-FIRED POWER PLANTS Emissions of air pollutants from coal-fired power plants c
41、an be significantly reduced by the application of emission control devices and procedures.Emissions of NOx can be reduced by:improved combustion processes(low NOx burners,fluidized-bed combustion)that lower combustion temperatures to minimize NOx formation 12,computer controls of the combustion proc
42、ess(CCC)to minimize NOx formation,the application of Selective Catalytic Reducers(SCR)to remove NOx from flue gases,Emissions of SO2 can be reduced by:burning low-sulfur coal to reduce SO2 formation,the application of Flue Gas Desulfurizers(FGD)using wet limestone scrubbing to remove SO2 from flue g
43、ases 12,fluidized-bed combustion using limestone injection to remove SO2 during combustion 12.Emissions of particulate matter can be reduced by:burning low-ash coal to reduce PM formation,the application of Electrostatic Precipitators to remove PM from flue gases 12,the application of bag-house filt
44、ers to remove PM from flue gases.There is no technology currently in place for the removal of mercury from power plant emissions,although bag-house filters apparently can do so to some extent,as well as removing particulate matter 13.However,it should be noted that a recent study has shown that merc
45、ury in soils in the USA(and its subsequent accumulation in the food chain)cannot be attributed to deposition from air of mercury emissions from fossil fuel plants and other human activities 14,so that the need to remove mercury from power plant emissions may not be as urgent as currently believed.At
46、 one time,particularly in the UK,tall stacks at fossil-fuel power plants were considered an adequate means of controlling human exposure to air pollutants from these plants.However tall stacks obviously do not reduce air-pollutant emissions but simply reduce ground-level concentrations by dispersing
47、 the pollutants widely 12.Emission control devices installed and procedures used at the OPG coal-fired plants are listed in Table 2.Electrostatic precipitators and low-sulfur coal are in use in all of the units at all five OPG coal-fired power plants and computer combustion controls and low NOx burn
48、ers are in use in all of the units at the three large plants.Flue gas desulfurizers are installed in only two units at the Lambton plant and selective catalytic reducers,which have just come into operation this summer,are installed in only two of the eight units at the Nanticoke and Lambton plants.T
49、ABLE 2 EMISSION CONTROL DEVICES AND PROCEDURES AT OPG COAL-FIRED PLANTS Information from References 2,4,13,15 Plant&Total Units Elect.Precip.Low S Coal CCC Low NOx Burners FGD SCR Nanticoke/8 8 units 8 units8 units8 units None 2 units Lambton/4 4 units 4 units4 units4 units 2 units2 units Lakeview/4
50、 2 units 4 units4 units4 units None None Thunder Bay/2 2 units 2 unitsNone None None None Atikokan/1 1 unit 1 unit None 1 unit None None Nevertheless,the use of electrostatic precipitators,low sulfur coal,combustion computer control and low NOx burners at the three large coal-fired stations and the