Urbanization, Energy, and Air Pollution in China: The Challenges Ahead: Proceedings of a Symposium (2004)

WEITANG FAN

China Energy Research Society

ZHUFENG YU

Clean Coal Engineering and Research Center

Although renewable energy technologies are making rapid progress in the world, 20 to 30 years hence, coal, oil, and natural gas will still be the primary sources of energy in China. The proven recoverable reserves of fossil fuels in the world are shown in Table 1. China ranks third in coal reserves, eleventh in oil reserves, and nineteenth in natural gas reserves. Thus, coal is much more abundant than other fossil fuels in China; proven recoverable reserves of coal amount to 114.5 billion tons, more than 10 times the total reserves of currently proven oil and natural gas reserves, based on equivalent calorific values.

In the past 20 years, China’s economy has grown at a rate of more than 7 percent annually, and the consumption of primary energy has increased every

FIGURE 1 Energy consumption in China in the past 20 years. Source: National Bureau of Statistics, 2003.

FIGURE 2 Consumption mix of primary energy in the world in 2001. Source: National Bureau of Statistics, 2003.

year (Figure 1). Fossil energy accounts for 86.9 percent of primary-energy consumption in the world, the highest proportion of which is from oil (38.5 percent). In China, however, the proportion of fossil fuels is 93.1 percent, the highest proportion of which is from coal (67 percent), 42.3 percent higher than the world average (National Bureau of Statistics, 2003). Consumption of oil and natural gas in China is 36.1 percent lower than in the rest of the world (Figures 2 and 3).

Oil constitutes about 50 percent of the mix of end-use-energy sources consumed in the world. Natural gas and electric power constitute ~ 18 percent each, and coal constitutes 9 percent (Figure 4). In China, coal accounts for 44 percent,

FIGURE 3 Consumption mix of primary energy in China in 2001. Source: National Bureau of Statistics, 2003.

FIGURE 4 Consumption mix of end energy in the world in 2001. Source: National Bureau of Statistics, 2003.

oil 33 percent, and electric power 16 percent (Figure 5). Thus, the proportion of coal in the end-use-energy mix is 35 percent higher in China than in the rest of the world, and the proportion of oil and natural gas is 32 percent lower than in the rest of the world.

In recent years, as a result of strengthened regulatory control of particulate emissions, 85.2 percent of power stations in China have installed electrostatic

FIGURE 5 Consumption mix of end energy in China in 2001. Source: National Bureau of Statistics, 2003.

FIGURE 6 Particulate emissions, 1995–2002. Source: SEPA, 2003a.

precipitators. This has led to a marked decrease in total dust emissions (Figure 6). Fine particulates (PM₁₀), however, are still a major pollutant in urban areas, especially in cities in northern China (SEPA, 2003a).

China has also strengthened its regulatory control of sulfur dioxide (SO₂) emissions. All new power plants that use coal with sulfur content of greater than 1 percent are now required to install desulfurization units; the rest are required to

FIGURE 7 SO₂ emissions, 1995–2002. Source: SEPA, 2003.

use low-sulfur coal. As a result, SO₂ emissions have been steadily reduced (Figure 7 and Table 2).

In 2001, 33.4 percent of the 341 cities monitored met or exceeded the national secondary standard for air quality (daily mean ambient concentrations of SO₂, nitrogen oxides (NO_x), and total suspended particles (TSP) of less than 0.15, 0.08, and 0.30 mg/m³, respectively), and 33.2 percent failed to meet the national tertiary standard of air quality (daily mean concentrations of SO₂, NO_x, and TSP less than 0.25, 0.15, and 0.50 mg/m³, respectively). Acid rain was evident in 161 cities (SEPA, 2003b).

In 1999, the government initiated a Clean Vehicle Action Campaign, and all new power stations with an installed capacity of more than 300 megawatts (MW) were required to install low-NO_x burners (Yu et al., 2004a). In recent years, the annual average concentration of NO_x emissions has remained stable, and in some

places has even decreased slightly, even though the number of automobiles has increased significantly (Table 3).

The average energy efficiency in China is about 34 percent, about 10 percent lower than in European Union (EU) countries (Zhou and Wang, 2002). Low energy efficiency is apparent in mine-mouth power generation and domestic coal consumption.

In 2000, the total production of electric energy in China was 1,350 terawatt hours (TWh). The average coal consumption for power generation was 390 gram coal equivalent per kilowatt hour (gce/kWh), 70 gce/kWh more than the world’s most efficient power plants would consume (Editorial Board of China, 2003). Thus, in 2000, China consumed an extra 94 million tons of coal equivalent (Mtce) for power generation, the equivalent of about 132 million tons (Mt) of coal.

There are about half a million industrial boilers in China with an average capacity of 2.5 tons per hour (t/h) and an average efficiency of 60 percent, 20 percent lower than the global average. Emissions from industrial boilers are higher than from power station boilers in almost half of Chinese cities. Thus, industrial boilers are the primary sources of pollution in many cities (Yu et al., 2004b).

The consumption per unit energy for industrial energy in China is 30 to 50 percent higher than in the world’s most highly industrialized countries. In

2000, energy consumption per ton of crude steel in large and medium-sized iron and steel enterprises and the overall energy consumption of cement producers in China, were 18.6 percent and 54.4 percent higher, respectively, than in Japan (CERS, 2003). There is great potential for energy conservation in these areas.

The efficiency of direct coal combustion for domestic use is very low, in some cases less than 20 percent. This is another area where great improvements can be made.

The energy technologies in many small and medium-sized facilities in China are out of date. In recent years, the state has promoted efficient, clean-combustion technology, clean-conversion technology, and new and renewable energy technology. Nevertheless, the development and use of these technologies has been limited.

Table 4 shows energy prices in the United States in 1999, where the price ratio among coal, natural gas, gasoline, and electric power (equivalent calorific value) was approximately 1:3:8:16. The major factors that influence the selection of energy sources and clean energy technologies are energy availability, environment, and economics. One of the problems in China is the uneven distribution of energy sources. Seventy-seven percent of coal resources are in the north, in the area of the Qinling Mountains and the Huai River; 85 percent of oil resources are in the area north of the Yangtze River; 82.5 percent of water resources are in the western part of China, two-thirds of it concentrated in the southwest (Liu, 2002). However, energy is consumed mainly in eastern and central China. Because of

the disproportional distribution of resources, coal has to be transported from north to south and from west to east in China. Currently, China is undertaking projects involving the transmission of electric power and gas from west to east.

Environmental requirements, energy availability, and energy prices vary greatly from city to city. Table 5 shows these variations for Beijing, Shanghai, and Chongqing. Beijing, the capital of China, which will be the host city for the

Olympic Games in 2008, will use natural gas as much as possible to guarantee good air quality for that event. The consumption of natural gas in Beijing is expected to increase from 1 billion m³ in 2000 to 6 billion m³ in 2008. Shanghai is expected to use a mix of energy resources. In addition to increasing the amount of natural gas it uses, Shanghai is devoting great efforts to the development of clean-coal technologies, such as supercritical power generation technology. Chongqing will use natural gas and hydropower as much as possible. At the same time, the proportion of electricity and heat converted from coal in Chongqing will increase. However, the proportion of coal in the mix of end-use energy will drop from 64.6 percent in 2000 to less than 50 percent in 2010 (Clean Energy Office, 2003).

At present, less than half of the coal produced in China is used for power generation; in the United States, the proportion is more than 90 percent (Table 6); in EU countries it is 80.4 percent (CERS, 2002). From 1996 to 2000, the installed capacity of power-generating units in China increased from 236.54 GW to 319.32 GW, with an annual growth rate of about 8 percent. During those years, coal-fired power generation accounted for 78 percent of total power generation (National Bureau of Statistics, 2003).

Because the proportion of coal used for power generation in China is expected to increase significantly, the development of advanced power-generation technology is very important because it will reduce the amount of coal consumed, improve generation efficiency, improve the environment, and reduce emissions of carbon dioxide (CO₂). At present, the focus is on supercritical and ultra-supercritical generating units, which have been used successfully in other countries (Yu et al., 2004a). With the development of desulfurization and denitrogenation technologies and decreases in operating costs, this technology is now fairly competitive.

There are currently about half a million small and medium-sized industrial boilers in China that supply heat to industries and residences. Industrial boilers consume nearly one-third of coal production, and their total emissions equal, or even exceed, those of power-station boilers in some cities. Industrial boilers are not expected to be totally eliminated in the next 20 years in China. Therefore, it will be necessary to retrofit them (Yu and Chen, 2001).

Currently, “retrofitting” usually means substituting clean fuels for coal; using washed coal (i.e., coal with a sulfur content of less than 0.6 percent); or using sulfur-capture briquettes or coal-water mixtures (CWM). Research has shown that the economics of coal-fired industrial boilers varies greatly with different fuels. In northern China, the operating cost ratio among washed coal, sulfur-capture briquettes, CWM, natural gas, light oil, and heavy oil is 1:1.2:1.5:3.1:3.9:2.3. Use of natural gas, light diesel, washed coal, briquettes, or CWM will all lower emissions to conform with the national environmental standard (CAE, 2001).

Low-sulfur coal provides the optimal ratio of economic benefits to environmental benefits. If all industrial boilers in China used low-sulfur coal, about 51 Mt of coal would be saved each year. Chinese cities must choose technologies and fuels for industrial boilers in accordance with environmental requirements, energy resources, and economic capacities (Yu et al., 2004a).

Combined heat and power generation (CHP) has comprehensive benefits, like energy savings, lower emissions, better heating quality, and increased peak-power-shaving capacity. Cogeneration plants in cities could replace a great number of scattered heating boilers and industrial boilers. CHP would ensure the heating supply in winter, would be beneficial for industry, could supply electric power to some residents, would effectively control air pollution, and would improve energy efficiency.

Circulating fluidized bed (CFB) technology is developing rapidly in China. In the past 10 years, CFB boilers with capacities of up to 220 t/h have been commercialized. CFB boilers provide high-efficiency, low-pollution combustion and have the great advantage of operating with inferior fuels. In-bed desulfurization and low-temperature combustion effectively reduce emissions of SO₂ and NO_x, and CFB boilers used with power-generating units would guarantee clean CHP. Even though CFB technology requires a higher initial investment than other heating systems, the economic and environmental benefits can offset the expense. Calculations based on equivalent calorific values show that the operating cost ratio among CHP based on CFBs, gas-fired boilers, and oil-fired boilers is about 1:1.7:1.2 (Yu et al., 2004a).

Table 7 shows a comparison of the energy sources for domestic consumption in China and the United States. Natural gas and electricity are the primary sources of domestic energy generation in the United States, whereas in China, coal is the main energy source. With rapid economic development and increasingly stringent environmental requirements, cities in China are increasing the proportion of clean-energy sources for domestic and commercial use as their economic capabilities and the availability of energy sources allow.

In Beijing, Shanghai, and well developed coastal zones where environmental requirements are stringent, natural gas, liquefied petroleum gas (LPG), and liquefied natural gas (LNG) are the main energy sources being considered for commercial and domestic purposes. For heating, natural-gas-fired boilers, CHP generation based on coal-fired boilers, and central heating will replace dispersed coal-fired boilers. In less developed areas and areas that lack clean-energy sources like natural gas, coal-fired CHP generation, central heating, and advanced industrial boilers that burn low-sulfur coal will be used for heating. Briquettes and coal-saving stoves, which will be the main modes of energy consumption for commercial and household purposes, are also being developed (Yu et al., 2004a).

By the end of 2000, China had built 35.6 million square meters of energy-conserving buildings. But the technical standards for energy-saving buildings in China are about 50 years behind those of more highly industrialized countries. Therefore, compared with developed countries, the level of energy-saving technology in China is low. Energy consumption per unit of residential area for

heating in northern China is three times the consumption in developed countries with similar climates (Wang, 2003). Thus, energy-saving design standards for buildings, improved building designs, new building materials, improved thermal isolation in buildings, and green lighting and cold-accumulation air conditioning could be extremely beneficial for China.

China has comparatively abundant geothermal resources, which should be developed as quickly as possible for power generation, heating energy, industrial energy, and medical and other uses in cities where conditions are favorable. In 2000, the geothermal heating area covered 6 million square meters in Tianjin. Beijing already exploits 8.8 million square meters of geothermal water per annum, equivalent to 75,000 tons of coal. This has reduced dust emissions by 750 tons, SO₂ emissions by 1,300 tons, and CO₂ emissions by 34,000 tons per year, thus reducing air pollution and environmental damage (Clean Energy Office, 2003).

In recent years, the number of vehicles in China has been increasing rapidly, causing severe tailpipe pollution in Chinese cities. NO_x, fine particulates, and dust emissions in large cities like Beijing, Shanghai, and Guangzhou exceed the national secondary standard. As the rate of urbanization increases, traffic density will also increase, and tailpipe pollution can be expected to worsen.

Bus Rapid Transit (BRT), a new transportation system, with costs comparable to those of an ordinary bus system and capacity roughly comparable to that of rail transport, was demonstrated in the city of Kunming during the 1999 International Horticultural Exposition. The Kunming Special Traffic Lane Demonstration Project was a joint project of Kunming and Zurich. The BRT system, which operates in a special traffic lane, features rapid boarding and de-boarding and a rapid ticket-purchasing system. Since 1999, the number of passengers transported daily has increased from 0.5 to 0.75 million, and BRT is now the hub of the municipal transit network. BRT has improved the flow of people and reduced the volume of traffic, thus decreasing tailpipe and noise pollution from vehicles (Municipal Planning Bureau of Kunming City, 2003).

At the end of 2001, the Chinese government initiated the Clean Energy Action Plan to control air pollution caused by coal combustion. Eighteen pilot cities were chosen to promote clean-energy sources and clean-energy technologies. The first step in the plan was to assess the status of energy consumption and environmental pollution in the pilot cities. The results showed that in 2000, total consumption of primary energy was 207.6 Mtce, average consumption of

FIGURE 8 Primary energy consumption mix in 18 cities in (a) 2000 and (b) 2005 (estimated). Source: Clean Energy Office, 2003.

primary energy per city was 11.5 Mtce, and average coal consumption per city was 7.7 Mtce. The proportion of coal consumption in 13 of the 18 cities was more than 60 percent. The average oil consumption per city was 2.3 Mtce; oil consumption in seven cities was more than 20 percent. The average natural gas consumption per city was 2.7 billion cubic meters; gas consumption in only two cities was more than 10 percent.

Figure 8 shows the mix of primary energy consumed in the 18 cities in 2000 and 2005. In 2000, mean coal consumption was around 64 percent; oil and oil products accounted for 27 percent; and the total of natural gas, hydropower, nuclear power, and wind power was about 9 percent. It is expected that by 2005, as a result of the implementation of clean-energy sources and clean-energy technologies, the consumption of coal for primary energy will be reduced to 60 percent, oil and oil products will increase to 29 percent, natural gas will increase to 5 percent, and hydropower, nuclear power, and wind energy will be about 6 percent.

In 2000, the proportion of coal was more than 60 percent in six cities, in the range of 40 to 60 percent in six cities, and less than 40 percent in six cities; the national average was 38.9 percent. This very high consumption of coal contributed significantly to the atmospheric pollution in these cities. By 2005, the mix of end energy consumed will become cleaner, and air quality is expected to improve tremendously.

The mean level of SO₂ emissions in the 18 cities was 140,000 tons, and the daily mean concentration of SO₂ emissions was 0.084 mg/m³; both were within the national secondary standard. The mean TSP emission was 65,000 tons, and the daily mean concentration of TSP was 0.39 mg/m³, exceeding the limit specified in the national secondary standard. Mean NO_x emissions were 44,000 tons,

and the daily mean NO_x emission concentration was 0.05 mg/m³, within the national secondary standard.

It is expected that by 2005 the mean SO₂ emission will be reduced to 110,000 tons in the 18 cities, and the daily mean concentration will be 0.062 mg/m³; the daily mean TSP emission concentration will be 0.22 mg/m³; NO_x emissions will basically remain unchanged. All emission levels will meet the national secondary standard.

Yinchuan is the capital of the Ningxia Hui Autonomous Region in western China. The total regional area is 3,500 km²; the urban area is ~1,300 km². The total population is more than one million. The GDP value of the municipality in 2000 was 10.4 billion yuan. Mines that produce excellent quality coal are located on the periphery of the city. Natural gas from gas fields in Shaanxi, Gansu, and Ningxia provinces is transmitted by pipelines through Yinchuan City to eastern China. The mix of energy sources for Yinchuan in 2000 is shown in Table 8 and Figure 9. Yinchuan is also in the “high-quality luminous energy zone”; that is, the

FIGURE 9 Consumption mix of end energy in Yinchuan in 2000. Source: Clean Energy Office, 2003.

annual mean of hours of sunshine is more than 3,000, making solar energy a promising prospect.

TSP and SO₂ emissions have been declining gradually in Yinchuan in recent years (Table 9). Currently, the main air pollutant is TSP; emissions in 2000 were 0.7 times higher than the limit specified in the national secondary standard. Emissions of SO₂ and NO_x were below the national secondary standard. The main cause of severe pollution was coal combustion for heating during the winter, when concentrations of the major pollutants, such as TSP and SO₂, were high. From April to May and from November to December each year, strong winds bring blowing sand and dust, which causes seasonal high concentrations of TSP.

Energy demand in Yinchuan is expected to be 3.7 Mtce in 2005 based on an average annual GDP growth rate of 9.5 percent and energy elastic coefficient of 0.31. The government’s goals for environmental quality in Yinchuan in 2005 are shown in Table 10 and Figure 10. Table 11 shows projected options for the mix of energy sources in Yinchuan based on these goals:

• Low option. Do not change the mix, and do not employ clean-coal technologies. Under this scenario, SO₂ and particulate emissions would greatly exceed the emissions targets.

FIGURE 10 Consumption mix of end energy in Yinchuan in 2005. Source: Clean Energy Office, 2003.

• High option. Replace coal with natural gas for all domestic heating. This would effectively improve air quality in 2005, and emissions would not exceed the national secondary standard. However, this option would require an investment of 2.48 billion yuan, or about 16.5 percent of GDP of Yinchuan City. In addition, annual operating costs would increase by 100 million yuan, which is unacceptable.

• Medium option. This option has been accepted for implementation. Clean energy will be substituted and clean energy technologies developed to meet the environmental targets for 2005. Six projects are planned: (1) substitution of natural gas for coal for domestic energy; (2) use of electricity instead of coal for some household cooking; (3) expansion of thermal power plants into CHP plants; (4) burning of low-sulfur coal instead of raw coal in industrial boilers; (5) equipping of industrial boilers above 6 t/h with desulfurization and flue-dust cleanup units; and (6) use of dual fuels (oil and gas) in automobiles.

Implementing the medium option will improve the end-energy sources substantially. Emissions of SO₂ will be reduced by 28,000 tons, and emissions of particulates will be reduced by 15,000 tons, which will satisfy both national and Ningxia environmental standards. The total investment will be 690 million yuan, or 4.6 percent of Yinchuan’s GDP in 2005 (Clean Energy Office, 2003).

As the case study of Yinchuan municipality shows, meeting ideal environmental standards for Chinese cities is not practical in the short term. To improve air quality and promote the rational development of clean-energy sources and clean-energy technologies, each city will have to work out a practical, realistic, step-by-step, local energy plan based on many factors, including national environmental targets, the availability of indigenous energy resources, and the economic capacity of the city. This is the only way China can achieve coordinated development of energy, the environment, and the national economy.

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