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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium Environmental Performance of Coal-Fired Power Plants Financed by the World Bank JACK J. FRITZ National Academy of Engineering This paper provides a summary of the findings from an environmental performance review of coal-fired power plants in China constructed between 1986 and 1997 and financed through World Bank lending operations. This review, carried out in 2000, included visits to six plants (600 to 1,200 megawatts [MW] each, Figure 1), an analysis of plant survey data, and recommendations for improving the environmental performance of coal-fired power plants in general (Jia et al., 2000). To date, this is the only analysis of its kind carried out in China. BACKGROUND Since the mid-1980s, the World Bank has assisted China in developing its electric-power industry, first by financing thermal power plants and hydropower plants, transmission and distribution systems, and renewable energy systems, and second by supporting policy initiatives to make the electrical energy sector more autonomous, environmentally sustainable, and financially viable. Since 1986, the World Bank has financed approximately 9,000 MW of coal-fired generation at an investment cost of $9.4 billion; the World Bank’s contribution was $2.9 billion. The plants were built to modern standards of operation and pollution control. From 1986 to 1997, environmental standards, guidelines, and enforcement institutions changed significantly. As increasingly prosperous urban residents clamored for improvements in air quality, environmental management became a major public policy issue. The power sector is often accused of being the biggest source of urban air pollution, but most ground-level particulate and sulfur
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium FIGURE 1 Coal-fired power plants visited by mission () and coal-fired power plants under construction, not visited by mission (). dioxide (SO2) emissions originate not from the power sector but from thousands of coal-fired boilers that are ubiquitous in most urban areas in China. Coal continues to be the predominant energy source in China, which is the world’s largest producer and user of coal. China uses approximately 1.4 billion tons of coal annually, and this figure continues to rise as primary energy consumption rises (5.4 percent annually from 1980 to 1996). In 1996, for example, coal accounted for 74.8 percent of total commercial energy production in China. The industrial sector is the largest consumer of coal at 68.5 percent of final energy consumption. With recoverable coal reserves estimated at 1,009 billion metric tons, China will certainly depend on coal as its main energy source for some time to come. China is the second largest power producer in the world after the United States, and from 1980 to 1997, both countries increased their generating capacity significantly. Electricity generation in China grew at an annual rate of 8.9 percent, reaching 254 gigawatts (GW) and producing 1,134 terawatt hours (TWh) annually. Since 1988, roughly 11 to 15 GW of generating capacity has been added annually. As a result, by 1997 most power shortages had been eliminated. Of the total installed generating capacity of 254 GW as of 1997, roughly 76 percent came from the burning of fossil fuels, 22 percent came from
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium hydropower, and roughly 2 percent came from nuclear power. Although the government has put a high priority on hydropower development, so far its efforts have been constrained by the great distances between the resources and the primary load centers (generally more than 1,500 kilometers). The rationale behind the controversial Three Gorges Project, now nearing completion, is based on the large scale of this energy source and expected flood-control benefits. In 1997, coal-fired power plants provided 82 percent of total electricity generation. The proportion of electricity provided by oil-fired plants has been declining since the 1980s because of falling production in the country’s aging oil fields. Gas supplies are only now coming on line, primarily for urban household use in Beijing. Nuclear power, which currently accounts for about 2.1 GW, is emerging as a significant source of electrical power. China, with 28 provincial and three large municipal power grids, has been actively pursuing system interconnection to improve efficiency and alleviate power shortages in the major load centers. When the government was restructured in 1998, the Ministry of Electricity was replaced by the State Power Corporation (SPC), which has emerged as the responsible agency for the power sector throughout China. WORLD BANK LENDING OPERATIONS The World Bank has financed nine coal-fired power plants in China since 1985. The first project was Beilungang #1, near Hangzhou. The most recent was Wai Gao Qiao in Shanghai, with a capacity that will eventually reach 5,000 MW. Total capacity is about 10,000 MW, with a total investment of $9,413,000 ($2,920,000 from the World Bank) (Table 1). The purpose of assisting China has been to satisfy the growing demand for electric power, improve efficiency, and reduce adverse environmental impacts. The leaders of China are well aware of the link between economic development and the ready availability of electrical energy. In fact, China has pursued an active policy of rural electrification for decades. China’s overwhelming dependence on coal for power generation has serious environmental consequences at every stage—extraction, transport, and power generation. The government has established a number of targets for stabilizing pollution at 1995 levels: (1) to restrict the discharge of particulates to 3.8 million tons annually for all coal-fired plants with more than 6 MW capacity on any one grid through the use of electrostatic precipitators with average collection efficiencies of 98 percent; (2) to restrict the discharge of SO2 by coal-fired power plants on any one grid to 6.5 million tons annually; (3) to adopt low-nitrogen oxide (NOx) technology for all new plants of 300 MW or more; (4) to ban the discharge of coal ash into waterways and recycle at least 40 percent (45 million tons) of fly ash annually; and (5) to require that 70 percent of wastewater from power plants meet national discharge standards.
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium TABLE 1 World Bank Lending for Thermal Power Plants in China (in thousands of U.S. dollars) No. Name Location Date Capacity (MW) Total World Bank Investment 1 Beilungang I Zhejiang May 1986 600 $1,044.09 $225.00 2 Beilungang II Zhejiang May 1987 600 $289.70 $165.00 3 Wujing Shanghai February 1988 2 × 300 $354.10 $190.00 4 Yanshi Henan December 1991 2 × 300 $459.60 $180.00 5 Zouxian Shandong March 1992 2 × 600 $957.40 $310.00 6 Beilungang II Zhejiang March 1993 2 × 600 $1,350.00 $400.00 7 Yangzhou Jiangsu February 1994 2 × 600 $1,081.40 $350.00 8 Tuoketuo Inner Mongolia April 1997 2 × 600 $1,300.50 $400.00 9 Wai Gao Qiao Shanghai May 1997 2 × (900 to 1,000) $1,898.00 $400.00 10 Leiyang Hunan March 1998 2 × 600 $678.00 $300.00 TOTAL 10,200 to 10,400 $9,413.60 $2,920.00
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium Environmental goals are also being pursued through electricity pricing reforms aimed at increasing cost consciousness and strengthening the enforcement capabilities of provincial environmental protection bureaus. The government also encourages utilities to locate power plants near mine mouth operations, to develop plants with a high heat rate, to retrofit older, smaller plants with new combustion technologies, to adopt coal washing and beneficiation technologies, and to adopt flue-gas desulfurization for plants that use medium- and high-sulfur coals. The government has also launched a $2 billion program to control sulfur emissions from a wide variety of sources, including the many small boilers scattered throughout Chinese cities. EVOLUTION OF CHINA’S STANDARDS AND GUIDELINES The first emission standards for coal-fired thermal power plants in China, applied in 1992 (GB 13223-91), were limited to emissions of particulates and SO2 from existing and modified plants. In 1997, the standards were updated and expanded to include emissions of NOx (GB 13223-96). Under these updated standards, power plants fall into one of three categories, depending on when approval was granted for original construction: Phase I, approved before August 1, 1992; Phase II, approved between August 1, 1992, and December 31, 1996; and Phase III, approved after January 1, 1997. As Table 2 shows, the old and new requirements for Phase I and II plants did not change. Major changes for Phase III plants include: (1) regulation of dust emissions independent of coal ash content; (2) criteria for both mass flow and concentration of SO2 in flue gas; and (3) standards for NOx emissions. Although the 1992 standards effectively addressed particulate emissions (some 90 percent of existing or upgraded plants, as well as new plants, have installed or retrofitted electrostatic precipitators), air quality in many Chinese cities has continued to deteriorate, necessitating tighter standards for SO2 and NOx. Recent interest has focused on the relationship of PM10 (fine particulate matter with a diameter of less than or equal to 10 micrometers) to total suspended particulates (TSP). Updates may have been made since 1997. Standards for liquid effluents were established for all industries in 1988 (GB 8978-88) and modified in 1996 (GB 8978-96). Clearly, liquid effluents are less of a problem for thermal power plants than for industries and municipalities. Major effluents from power plants include runoff from coal piles, sanitary wastes, chemical wastes from various subsystems (e.g., boiler blow down), and cooling water. Typically, much of the cooling water and chemical wastewaters are recirculated, partly because the dilution of wastewater to meet the standard is prohibited. The effluent standards for power plants are the same as for industrial and municipal discharges, a five-step system that classifies ambient water quality according to the ultimate use of the receiving water (e.g., drinking, industrial, agricultural, etc.).
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium TABLE 2 Chinese National Standards for Flue-Gas Emissions from Coal-Fired Power Plants Pollutant GB 13223-91 Plant Type Existing Power Plant New, Extended, Reconstructed ESP Other Dust Control Power Plant > 670 t/h or Urbanb < 670 t/h and Urbanb Particulate (mg/Nm3) 200–1,000a 800–3,300a 150–600 500–2,000 Sulfur dioxidemass flow (t/h) Correlation based on average wind speed and stack height — Sulfur dioxide-concentration (mg/Nm3) — — — — Nitrogen oxides (mg/Nm3) — — — — aRange reflects ash content of coal. Lower value is < 10 percent; higher value is > 40 percent; intermediate values are specified in the regulation. bValue depends on boiler size (coal feed rate in t/h) and/or regional characteristics. cRange reflects regional characteristics: lower value is for urban area; upper value is for rural area. EVOLUTION OF WORLD BANK GUIDELINES The evolution of World Bank guidelines goes back to the 1970s, but they were not compiled and made a formal requirement until 1984. Initially, these guidelines were not the ironclad requirements they have become of late. The initial emphasis was on controlling emissions of particulates, SO2, and NOx from any combustion process. The guidelines include two types of standards: mass-based standards (e.g., tons per day) and concentration-based standards (e.g., milligrams per normal cubic meter [mg/Nm3]). Mass-based emissions can be used to calculate concentrations of SO2 in flue gas using the heat rate (gram coal equivalent per kilowatt hour [gce/kWh]) and flue-gas flow (e.g., 350 Nm3/gigajoule [GJ], with 6 percent excess O2). As Table 3 indicates, the 1984 guidelines for particulates were based on concentration; for NOx they were based on mass per unit heat release; and for SO2 they were based on mass. In 1997, guidelines were written specifically for thermal power plants. At that time, World Bank membership was expanded to include the countries of
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium GB 13223-96 Phase I II III ESP Other Dust Control > 670 t/h or Urbanb < 670 t/h and Urbanb Urban or Rural 200–1,000a 800–3,300a 150–600 500–2,000 200–600c Correlation based on average wind speed and stack height — — — — 1,200–2,100d — — — 650–1,000e dRange reflects sulfur content of fuel: lower value is for coal containing > 1.0 percent; higher value is for coal containing < 1.0 percent. eRange reflects boiler type: lower value is dry bottom; upper value is wet bottom. Source: Jia et al., 2000. Eastern Europe and the former Soviet Union, where the power sector required tighter, but more flexible, guidelines. The basic differences between the 1984 and 1997 guidelines are: (1) tighter control of particulates (down to 50 mg/Nm3) and (2) a mass-based standard for SO2, but with a ceiling for both mass and concentration. The new standards provide more flexibility in the choice of coal but reduce emissions overall. AMBIENT AIR QUALITY TRENDS AND STANDARDS Monitoring data from 1991 to 1998 for 60 medium-sized and large cities in China showed some improvements in ambient air quality. Forty cities experienced reductions in TSP, and 50 had reductions in SO2. The median concentration of SO2 in 32 cities with populations of more than one million dropped from 100 to 62 µg/m3. In smaller cities, the average concentration dropped from 50 to 32 µg/m3. Anecdotal evidence suggests, but does not prove, equivalent declines in health-related damage based on typical linear dose-response methodologies.
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium TABLE 3 World Bank Guidelines for Air Pollution from Thermal Power Stations Pollutant 1984 Guidelines 1997 Guidelinesb Dust Emissions (mg/Nm3) 100–150a 50 Ambient (µg/Nm3) Daily maximum Annual average 500 — Sulfur Dioxide Emissions (tons/day) 100–500a 0.2/MWe for first 500 MWe 0.1/MWe for subsequent capacity (maximum 500 tons/day) and < 2000 mg/Nm3 Ambient (µg/Nm3) Daily maximum Annual average 500 — Nitrogen Oxides Emissions 260 (lignite) 260 (coal) (nanograms/joule) 300 (coal) 1,500 (low volatile coal) Ambient (µg/Nm3) Annual average 100 — aAllowable value for ambient levels; the lower the ambient level, the higher the allowable emission level. bUpdated World Bank guidelines do not provide ambient values. TSP levels, however, remained fairly high, with only a few decreases in some urban areas. The median concentration in China’s 32 largest cities dropped from 334 to 332 µg/m3; in smaller cities, it declined from 260 to 215 µg/m3. In some large cities, such as Tianjin and Beijing, which had significant increases in population, TSP increased significantly. With the recent introduction of natural gas to Beijing, levels of both TSP and SO2 are expected to decrease appreciably. Ambient air quality standards were promulgated in 1982 (GB 3095-82) and updated in 1996 (GB 3095-96) (see Table 4). The standards include PM10 based on epidemiological evidence suggesting that much of the health damage from air pollution is caused by exposure to fine particles. Ambient air quality standards are based on an air-quality classification system: Class I areas are natural conservation districts, resorts, and tourist areas of historic interest; Class II areas include urban, residential, commercial, and rural areas; Class III areas are industrial areas or areas with high traffic volumes. A key aspect of the 1996 makeover was an increase in the time and coverage of monitoring. Under the original regulatory regime (prior to 1996), the following protocol was standard:
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium TABLE 4 Chinese Ambient Air Quality Standards (µg/m3) GB 3095-82 GB 3095-96 Air Shed Classification Air Shed Classification Pollutant I II III I II III TSPa Annual average — — — 80 200 300 Daily maximum 150 300 500 120 300 500 One-time maximum 300 1,000 1,500 — — — PMb <10 µ Annual average — — — 40 100 150 Daily maximum 50 150 250 50 150 250 One-time maximum 150 500 700 — — — Sulfur Dioxide Annual average 20 60 100 20 60 100 Daily maximum 50 150 250 50 150 250 One-time maximum 150 500 700 Nitrogen Oxides Annual average — — — 50 50 100 Daily maximum 50 100 150 100 100 150 One-time maximum 100 150 300 — — — a Total suspended particulates. b Particulate matter.
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium four monitoring campaigns per year (one every three months) five- to seven-day monitoring campaigns four six-hour intervals per day 15 to 20 minutes of monitoring per interval At best, the original protocol provided monitoring data for 37 hours per year, or a sample window of 0.43 percent, hardly a statistically relevant sample. Because the World Bank required background ambient air quality data for at least a year prior to construction, an entirely new approach was necessary. Under the monitoring requirements instituted in 1996, the sampling frequency was increased: SO2/NOx 144 days per year 18 hours per day 45 minutes per hour TSP/PM10 60 days per year 12 hours per day 45 minutes per hour Thus, the sampling window increased by a factor of 52 for SO2 and NOx and a factor of 14.5 for TSP and PM10. The new sampling procedures provided more representative data and reduced the barrier to further investment in the power sector by the World Bank and other donors. Standards for noise levels were also enacted, as well as standards for the thermal pollution of receiving waters. Finally, in 1996, the Ministry of Electric Power (the forerunner of SPC) issued its own regulations for environmental monitoring. In addition to the new standards and guidelines, the published documents described the management, budget, equipment, reporting, compliance, and mitigation by each plant. All power plants were required to comply within six months; thus, today we have a rich database for the power sector. THE POWER PLANT REVIEW Objectives The power plant review (Jia et al., 2000) was undertaken for several reasons. First, the World Bank had never carried out a comprehensive environmental review of its investment in the thermal power plant sector in China. Thus, one objective was to provide an assessment of compliance with both Chinese and World Bank environmental guidelines. In addition, the review provided an assessment of (1) adherence to an environmental management plan governing daily
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium power plant operations and (2) the overall impact of environmental oversight of the power sector as a whole. In addition to a review of day-to-day environmental performance, the review provides an ex post facto assessment of compliance with environmental management plans, as described in the documentation required by the World Bank and the Chinese government, which was a condition of the loans in all cases. The environmental management plans describe a host of measurements, standards, and procedures that must be followed in operating plants; these are generally considered standard operating procedures in most developed countries. The SPC was also interested in using the results to provide guidance to provincial power authorities with power plants in the pipeline on compliance with environmental guidelines in the future. Basic Findings The review team of three engineers visited six of the nine plants financed by the World Bank during the 1990s. These were state-of-the-art, large-scale units equipped with particulate and sulfur controls (or they used low-sulfur coals), as well as treatment systems for discharged cooling water, sanitary water, and coal pile runoff. Table 5 shows the basic characteristics of the six plants. Most of the plants the team visited were in compliance with both World Bank and Chinese guidelines as applied at the time of construction and initial operation. Plants built after 1994, primarily use high-efficiency precipitators and low-sulfur coals, and have improved overall designs. Unfortunately, older plants continue to use high-sulfur coal with less control. Industrial boilers, which also continue to use high-sulfur coal, generally have lower stacks, and are much smaller than power plants, tend to spread particulates and SO2, mostly in heavily urbanized areas. A clear benefit of the involvement of the World Bank has been to encourage environmental management of overall plant operations (including the treatment of cooling water and wastewater) at other plants in the same power grid. In some cases, older units have been retrofitted with precipitators that meet both Chinese and World Bank standards. The World Bank’s continued policy advice and emphasis on incremental environmental improvement, and the resulting use of more efficient power technologies, have led to a much more efficient power sector than would have been possible otherwise. Table 6 outlines some of the positive impacts on China’s power sector. The World Bank has also promoted a vigorous social agenda that includes public participation, consultation, and compensation for assets appropriated by the state for plant sites. The essence of this policy is to use “resettlement action plans” to ensure that affected parties are not unduly negatively impacted. To implement this policy, the World Bank and the Chinese government developed a rather complex process that includes compensating people forced to give up land and providing information to local residents about expected environmental
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium TABLE 5 Basic Characteristics of Power Plants Basic Characteristics Beilun I Wujing Yanshi Beilun II Zouxian Yangzhou Unit capacity (MW) 600 300 300 600 600 600 Unit number 2 2 2 3 2 2 Stack height (m) 240 210 240 240 240 240 Ash content (%) 14.7% 7.9% 30.6% 15.5% 22.4% 10.9% Sulfur content (%) 0.85% 0.62% 0.81% 0.63% 0.70% 0.36% Heat value (kJ/kg) 22966 22474 17201 22404.8 22535 21610 ESP efficiency (%) 99.80% 99.80% 99.20% 99.90% 99.60% 99.80% Heat rate (gce/kWh) 307 332 350 300 320 337 Plant efficiency (%) 40.1% 37.1% 35.2% 41.0% 38.4% 36.5% Flue-gas volume (Nm3/kg) 8.0381 7.8659 6.0203 7.8417 7.8873 7.5635 Coal consumption (t/d) 11265 6224 8573 16925 11966 13141
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium TABLE 6 Positive Impacts of World Bank Involvement Technology Transfer Institutional Efforts First 600 MW subcritical unit in China Preparation for possible privatization of some components of the power system. First supercritical 900/1,000 MW unit in China Development of Chinese environmental assessment procedures for power plants that parallel World Bank policies. Low-NOx burners Continuous environmental monitoring equipment New national standards for ambient air quality that include requirements for fine particulates (PM10). High-efficiency electrostatic precipitators and flue gas desulfurization New emission standards that include requirements for NOx and a commitment to sulfur-control measures for coal with more than 1 percent sulfur. Pilot test of tradable sulfur emissions impacts. The six plants visited for the review had followed the long-standing Chinese tradition of providing compensation, but public participation was not always solicited in an open and helpful way. In some cases, local resistance had been quieted by the perception that the project would provide jobs. Crews from all six plants visited local municipalities to check on ambient air quality conditions. Traditionally, this had been the responsibility of local environmental protection bureaus, which rarely had sufficient staff or monitoring equipment. Issues and Analysis As a result of the review, several issues were identified that require further consideration and analysis. Most of these are related to the application and interpretation of environmental standards and their impact on costs and long-term environmental management of the power plant sector. Sulfur Dioxide Emissions The mass-based standard for SO2 emissions could be interpreted as being overly strict, compared to the concentration-based standard, especially for plants that plan to expand. For example, approximately 0.2 tons per megawatt daily (t/MW/day) equals 8.3 g/kWh of SO2. According to 1997 data from SPC, the average level of SO2 emissions from all thermal power plants in China is 84.6 g/kWh, 10 times the World Bank standard. The average level of mass-based emissions of SO2 from World Bank-financed power plants is 3.69 g/kWh,
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium only 4 percent of the national average. These figures show the positive impact of World Bank-financed plants on the power plant sector. If the sulfur content of coal could be reduced at reasonable cost (which is questionable) to less than 0.5 percent through coal washing, SO2 emissions could meet the new World Bank standard (1,200 mg/Nm3) without flue-gas desulfurization. The sulfur content of coal used by most of the plants in the survey ranges from 0.4 to 0.9 percent. The heating value of coal and overall plant efficiency are clearly linked. Cleaner coal with concomitant higher heating value means that less coal has to be burned to produce the same amount of energy, which results in fewer emissions, less wear and tear on plant systems, etc. Plants that burn low-quality coal with low heating value and relatively high sulfur content (mostly near mine mouths [e.g., Yanshi]) have difficulty meeting new World Bank standards for emissions. Figure 2 shows the general compliance of the six plants visited by the review team. All six clearly met the World Bank standard for SO2 emissions. Particulate Emissions The Chinese standard for particulate emissions is much less stringent than the World Bank standard. Nevertheless, three of the six plants we visited, Beilungang I and II, Wujing, and Yangzhou, currently meet the World Bank’s FIGURE 2 Compliance for SO2 emissions.
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium FIGURE 3 Compliance for particulate emissions. new standard. Two other plants, Yanshi and Zouxian, will have to improve the quality of coal or the efficiency of the electrostatic precipitators to meet the World Bank standard (Figure 3). When the Yanshi plant was built, a low-efficiency precipitator was specified to favor a local contractor, which resulted in the plant being out of compliance. Options for meeting the new standard should not be limited to improving the efficiency of the precipitator; improving the quality of coal by reducing ash content and increasing heating value should also be considered. According to data provided by Yanshi, the estimated cost of renovating the precipitator is $2.2 million, equal to $0.26 million per year for a 20 year loan at 10 percent interest ($0.14 per ton). This option appears to be much less costly than coal washing, which would cost $15 to $30 per ton. The World Bank standard for particulate emissions was changed in 1997 from 150 mg/Nm3 to 50 mg/Nm3. The impact of this change on PM10 and smaller particulates1 (the most dangerous particulates to human health) is still unclear. Even if particulate emissions can be reduced to 50 mg/Nm3 by improving the efficiency of the precipitator, fine particulate emissions may not be reduced proportionally. Thus, adopting the new World Bank standard may not lead to the expected reductions in PM10. Both the World Bank and the Chinese government are studying a separate requirement for very fine particulate emissions, but neither has adopted one as yet. 1 The World Bank standard in 1997 was for PM10, but current analyses focus mostly on PM2.5.
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium Modeling of Dispersion and Thermal Pollution The incremental contribution of power plant emissions to ambient air quality is normally determined by standard mathematical models (usually some variant of a Gaussian dispersion model). The results can then be combined with estimates of background air quality to produce an overall estimate of air quality with the proposed power plant in operation. These estimates can then be compared to air quality standards to determine whether or not the standards would be met. The environmental assessment process includes a formal requirement for air quality modeling, which is generally done by a local or regional design institute that specializes in assessment techniques. However, after reviewing the dispersion models, it was apparent that the models are not being taken very seriously. The crews that take ambient air quality readings do not compare them against model results, and the coefficients in the models are taken from textbooks. Improving the models will require correlating model results with empirical results. To get a more complete picture of ground-level conditions based on the concentration of SO2 in flue gas, ambient air quality at ground level can be determined by calculating the portion of SO2 that touches the ground under the most unfavorable conditions. In the plants visited by the review team, the maximum additional pollution from any one plant was only about 5 percent. Even though the models on which this estimate is based may be suspect, we can conclude that the portion of urban air pollution attributable to the power sector is minor compared to the portion from other sources. Generally, the World Bank requires one year of data on ambient air quality as background, and collecting these data may entail significant costs. In addition, between the time background data are collected and the time the power plant goes into operation, ambient conditions may change appreciably, making the impact analysis difficult, if not impossible, to verify. We found this problem at all of the plants we visited. Nevertheless, because modeling indicated that power plant contributions to overall ambient pollution were never more than 5 percent of ambient air quality limits, we concluded that for all practical purposes, power plant emissions superimposed on ambient conditions were well within the standard signal-to-noise ratio for ambient conditions. Thermal pollution was also the subject of extensive physical and mathematical modeling (e.g., Wai Gao Qiao plant in Shanghai). Thermal pollution modeling, which is normally done when there are cooling system discharges, can be complex and expensive to perform and verify. In addition, thermal pollution is very difficult to measure in situ, and the World Bank standard is somewhat vague. (The 1997 guidelines allow an increase of 3°C at the edge of the mixing zone for waters at 28°C or higher.) Predictions of ambient air quality and (in some instances) thermal pollution, which are integral to the environmental assessment process, must be verified after plant operations begin to confirm the modeling and check impacts. A review
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium of data from the six plants we visited indicated a lack of commitment to confirming air and water quality predictions, even though the plants were basically in compliance with World Bank and Chinese standards. Management of Ash Ash disposal remains a prominent issue because local coals often have a high ash content. Environmental assessments usually include references to using ash as a construction material, but the team did not see efforts being made to do this. Nevertheless, ash was managed in a relatively sound and environmentally safe way at all of the plants we visited. Ash is disposed of in large ash ponds (measuring several hundred meters on each side), a method that requires storage silos at each plant, and transport either via sluice pipes several kilometers long, truck, or rail. The facilities for treating ash add significantly to the cost of operations. Disposal sites tend to be near bodies of water (mud flats) or in areas where farming is a marginal activity. Ash yards require significant civil works to ensure that the materials are contained and that drainage is strictly controlled. At some plants, including the most modern plant we visited, the ash yards and ponds were nearing capacity, and new sites for ash disposal will be required. In some cases, ponds have become desiccated, and ash has become airborne as particulate, which has caused problems for farmers and residents. In other areas, rain has washed the ash off site. Because storage capacity near the plants is limited, more mine-mouth methods, such as reducing ash via coal washing, should be explored. Water Pollution To meet World Bank and Chinese standards, municipal wastewater from power plants requires secondary treatment prior to discharge. At some plants, the volume of wastewater was too small to justify a wastewater treatment system. At other plants, the wastewater treatment process was the last system to be implemented. Because wastewater usually includes cooling water and sanitary water and, sometimes, coal pile runoff, it is difficult to treat via biological processes. Nevertheless, typical, off-the-shelf biological processes are being used, and not always effectively. In some cases, the influent water for cooling is of such poor quality that the effluent standards actually represent an improvement in water quality. Based on this finding, some have concluded that power plants should not be required to treat effluents at all. CONCLUSIONS China has a number of world-class power plants equipped with the latest pollution abatement technology and has made significant progress in developing
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Urbanization, Energy, and Air Pollution in China: The Challenges Ahead - Proceedings of a Symposium its power industry. In addition, China has taken the first steps toward controlling pollution from that industry. Nevertheless, compliance monitoring and enforcement are not uniform and are not implemented everywhere in the country. Significant progress has been made in assessing the environmental impact of proposed plants, but not as much progress has been made in ensuring that pollution control systems are operated once the plant is built. As China becomes more prosperous, the need for electrical energy will increase; hence it will burn more coal. It is, therefore, imperative that power sector pollution control remain a high priority. BIBLIOGRAPHY AND REFERENCES Jia, L., Baratz, B., and Fritz, J. 2000. Environmental Performance of Bank-Financed, Coal-Fired Power Plants in China. Washington, D.C.: World Bank, East Asia Environment and Social Development Unit. World Bank. 1998. Pollution Prevention and Abatement Handbook. Washington, D.C.: World Bank. World Bank. 2001. China: Air, Land, and Water Environmental Priorities for a New Millennium. Washington, D.C.: World Bank.
Representative terms from entire chapter: