当前位置：文档库 › 电气专业外语论文

电气专业外语论文

IEEE power & energy magazine

july/august 2005

1540-7977/05/$20.00?2005 IEEE

IN JUST A QUARTER CENTURY ,CHINA ’S ECONOMY has transformed itself from a relatively closed agriculture-based system to a market-oriented system with World Trade Organization membership and a reputation as the manufacturing capital of the world. The electric energy infrastructure is the engine that drives economic developments. Recent expansion in electric gener-ation and transmission has been phenomenal. China now ranks second in the world in terms of installed generation capacity and electricity produc-tion. However,it lags far behind in terms of per capita electricity consump-tion. Indeed,with roughly 1,000 kWh per capita per annum,China is still in the

category of a developing country. The continuing economic development of the nation requires sustainability in electric energy supply,and the effective use of hydro and other energy sources necessitates an expansive and reliable transmission network. Simultaneous with technol-ogy solutions,institutional and economic structures must be in place. The challenges to electric energy supply in China are tremendous.

In this article,recent developments and future challenges in generation,transmission,and the market aspects of electric energy systems in China are described. For each of the subjects,the major challenges being faced and the measures and policies being taken are listed.

Electricity Supply in China

Since the economic reform in 1980,China has experienced unprecedented economic growth. Gross domestic product (GDP) has jumped more than 800%. However,the corre-sponding growth in primary energy consumption has increased only 278%. The energy intensity,measured

in terms of energy consumption in kilogram of coal

equivalent (kgce) per economic output in dollar of

Chinese yuan,dropped from 1.33 to 0.46. There are

many factors contributing to this improvement in the

more efficient usage of energy. A major one may be

attributed to the fact that the share of electricity uti-lization (a more efficient means of energy usage in

most cases) in the total energy consumption has more

than doubled,up from 20.6% to 43.8%. As a result,the

growth in electricity has surged 634% since 1980. Fig-ure 1shows the growth in the economy,and Figure 2shows the increase in the share of electricity in total

energy consumption.

500450400350300250200

150

100

198019851990199520002003figure 1.GDP in billions of U.S. dollars, indexed at 1980.

july/august 2005

IEEE power & energy magazine

The installed generation capacity in China has reached 440.7 GW at the end of 2004,with annual production of 2,187 trillion Wh,making it the second highest in the world. At present,about 75% of generation is from thermal power plants,25% from hydro power plants,and a very small percentage (0.4%) from nuclear. Figure 3depicts the trend in annual installed gener-ation capacity and production since 1980. The average growth rate of installed capacity during this period is over 7.8%. The growth in electricity consumption in the last two years has been particularly noteworthy. In 2003,the electricity consumption increased 15.3% over the previous year,a growth,as expected,that is largely due to an increase in industrial and urban residential usage (consumption in the agriculture sector has in fact declined slightly).

Part of China experienced a more than a 20% increase in electricity consumption in 2003,causing 21 out of 29 provinces to suffer power shortages. The situation worsened fur-ther in 2004; 26 provinces had to shed load,especially in the highly developed industrial regions of Jiansu and Zhejiang,where factories had to be shut down part of the week,resulting in a loss of GDP worth tens of billions of U.S. dollars. The shortage in 2004 was estimated at around 35 GW. The immediate response from the government and the private sectors was to expedite the approval of the construction of new power plants. More than 68GW of capacity are planned to be added in 2005 and 79 GW in 2006. After 2007,the power shortage problem should be eased.

Challenges in Electricity Supply

Per capita annual electricity consumption in China today is roughly 1,000 kWh,compared with more than 5,000 kWh in Hong Kong and over 12,000 kWh in the United States. The number

will definitely rise as China’s economy continues to grow and people’s standard of living further improves. Some

forecasts put the installed generating capacity at a level of

950 to 1,000 GW by the year 2020,or 250% of today.

Such growth imposes tremendous challenges to the sus-tainability of power system developments in a multitude of dimensions for the next decade. The resources for elec-tricity generation must be diversified,the environmental issues must be adequately addressed,efficiency improve-ment and conservation must be encouraged,and,above

all,sources for capital investment must be ensured.

The government’s diversification plan calls for a reduction in the dependency on coal generation,which has a significant adverse environmental impact,from 75% today to 65% by 2020,upholding hydro generation

5040

100

198019851990199520002003

figure 2.Percentage share of electricity in total energy con-sumption.

at around the present percentage level and increasing more environmentally benign gas generation to 6%,nuclear to 3–4%,and renewables to 2%.

China is endowed with large hydro potential; it is estimat-ed that the exploitable hydro capacity is 378 GW,ranked first in the world. The government has an aggressive plan to develop hydro generation from the present 108 GW to 260GW by 2020 (thus upholding hydro at 25% of the total gen-eration capacity). The most famous hydro power project under construction,which will become the largest such plant in the world,is the Three Gorges. Three Gorges,due for com-pletion in 2009,will consist of 26 generators of 700 MW each,or a total of 18.2 GW. After these units are commis-sioned,six more generators will be installed in an under-ground power house,and the total capacity of the plant will then become 22.4 GW with an annual production of 84.7 tril-lion Wh. The year 2003 was a landmark year for the project;six units began to generate electricity. Three Gorges lies in the middle stream of the Yangtze River. The upper stream of

the Yangtze River,called Jinshajiang ,has exploitable hydro of more than 18 GW and is being developed. In Yunnan,Southwest China,the Lancang River (called Mekong River in Southeast Asia) also has significant hydro potential.

The first nuclear power plant in China was a 300-MW unit constructed in 1991. Today,there are eight units with a total capacity of 6,840 MW. The government is planning to build 36-GW nuclear generation by 2020. The deployment of nuclear power plants is not without controversy,notably the issues of safety,security,and waste disposal. The government in recent years has also started to encourage renewable power generation with the enactment of preferential regulation. The China Meteorology Research Institute estimated that the exploitable wind energy potential in China is as high as 1,000 GW:250 GW on land and 750 GW offshore. Current-ly,there are 40 wind farms,with a total of 1,042 units and a total capacity of 567 MW. Wind and other renewable energy sources are expected to reach 20 GW capacity,or 2% of the total capacity,by the year 2020.

Beginning in 2002,China intensified legal construction on environment protection and resources conservation and launched a series of rules and regulations for levying pollu-tant discharge fees,emission standards of air pollution for thermal power plants,standards on water extraction quotas,etc. Power plants are beginning to use clean coal technolo-gy to reduce SO 2and NO X . Newer power plants must com-ply with the air pollution protection standards. Several flue gas desulfuration techniques are used in China. The first 450 t/h circulating fluidized bed boiler was installed in 2003. By the end of 2003,the capacity equipped with desulfuration equipment constructed and under construc-tion amounted to 20 GW.

In terms of conservation of resources,from 1980 to 2003 the net coal consumption rate decreased from 448gce/kWh to 380 gce/kWh,and the line losses decreased from 8.93% to 7.71%. According to some statistics,the average cost of products per kWh of energy in China is still three times higher than the world average and ten times higher than in the United States. There is a lot of room for energy conservation. For example,air-condition-ing load constitutes about 30% of the summer load in Bei-jing; considerable energy may be saved by improving air-conditioning efficiency. China has recently conducted several demand-side management (DSM) studies,all with positive conclusions. Experimental peak load pricing is being conducted. The government has successfully pro-moted DSM to alleviate somewhat the pain of power shortages in 2003 and 2004.

In addition to the challenge to the environment,China’s continued appetite for electricity also imposes tremendous demand for capital to fund the power projects. The state-owned industry has to be restructured in order to attract pri-vate funding for generation projects,as discussed later in this article. The first step has been the corporatization of the state-owned enterprise.

IEEE power & energy magazine

july/august 2005

figure 3.Total installed generation capacity in GW (red columns) and annual electricity production in 10 trillion Wh (blue columns).

figure 4.Geographic map of six regional power systems (NC: North China; EC: East China; CC: Central China; SC:South China; NW: Northwest China; NE: Northeast China).

CC EC

Xinjiang

Xizang

july/august 2005IEEE power & energy magazine

transport a massive amount of electricity over the geographic span of a huge country,and this is just the beginning. The challenges are to squeeze even more electricity into such a network,to manage this complex ac/dc network,and to maintain a high level of reliability for electricity supply.

The current backbone of 500-kV ac and ±500-kV dc trans-mission systems is considered too weak for transmitting large blocks of power over a long distance for the future power sys-tems in China. The first 750-kV transmission project was com-missioned in 2003 in the northwest region of China. China’s transmission system could be strengthened further by the deployment of ultrahigh-voltage (UHV) transmission,e.g.,a voltage level higher than 1,000-kV ac and ±800-kV dc trans-mission lines. Studies and plans are under way for incorporat-ing UHV transmission into the existing power grid of China. Since an operating experience of 1,000 kV transmission is scant and manufacturing is lacking,a lot more research and development (R&D) must be accomplished in a short period of time before ambitious plans can be realized.

To enhance transmission capability and system dynamic performance of the ac networks,flexible ac transmission system (FACTS) devices are employed throughout China. There are six SVC (static var compensators) installed on 500-kV transmission systems. A ±20 Mvar STA TCOM (static compensator) developed by Tsinghua University was installed on the 220-kV network in Henan Province. A TCSC (thyristor-controlled series compensator) was installed at a 500-kV substation in the southwest province of Guangxi in 2003,successfully increasing the power transfer capability from west to east by 300 MW. Another TCSC was installed on a 220-kV system. There are immediate plans for two more TCSC projects,one in the northeast and one at Three Gorges. Research into the deployment and manufacturing of FACTS devices is very active in China.

Since the mid-1980s,control centers with supervisory control and data acquisition (SCADA) or energy manage-ment systems (EMS) have been employed extensively to control and manage the transmission networks. Digital relays and substation automation are widely used. The con-trol centers in China are structured in a three-tier hierarchical architecture. On the top is the National Control Center and underneath are six regional control centers. Each regional control center covers three to six provincial or municipal control centers. Control centers are all equipped with advanced application software that includes static security monitoring and control. As the network becomes more and more complex and the demand for higher reliability becomes more stringent,PMU (phasor measurement units) and W AMS (wide-area measurement system) are beginning to be employed in earnest in China. The first PMU was introduced in 1996 on the South China grid. Currently there are over 30 PMUs installed:five on Three Gorges transmission system, six on the north grid,nine on the northeast grid,nine on the east grid,and six on the south grid. The objective of using PMUs and W AMS is to enhance wide-area system protec-tion and dynamic security monitoring and control for the future transmission systems in China and ultimately improve reliability of electricity supply.

Electricity Market

The pace towards reform and restructuring of the electricity industry in China is deliberate and cautious. Part of the Min-istry of Electric Power was first transformed into the State Power Company of China (SPC) in 1997 to separate the enterprises from the administrative functions. Independent power producers (IPPs) are encouraged to ease the burden of capital expenditure from the state for power plant construc-tion. Six experimental provincial or municipal electricity markets were established in 1999–2000. In 2002,major steps were taken towards industrial reform and restructuring:gen-eration and transmission are unbundled and corporatized,and a regulatory commission was formed. The generation is care-fully regrouped into five group companies (Huaneng,Datang, Huadian,Guodian,and Zhongdian) with the incorporation of IPPs and publicly listed companies. Each of the five compa-nies has a similar composition in terms of the scale of assets, the makeup of installed capacity,etc.,and none has more than 20% of any local market share. All generating compa-nies have to compete in the market indiscriminately to supply power. Other participants in the market include local generat-ing companies,additional small generating companies,and IPPs with foreign investment.

The grids are grouped into two companies:the South China Grid Company covers the south grid consisting of five south and southwest provinces,and the State Power Grid Company covers the rest of the five regional grids. Enough generating capacity (around 10–20%) is kept by the grid companies to ensure reliable operation,frequency modula-tion,and peak load following. Each regional grid operates an electricity market. More than 80% of the demand based on long-term (i.e.,annual) bilateral contracts. The remaining demand is traded in the monthly and day-ahead markets oper-ated by an Electricity Dispatch and Trading Center (EDTC) of the region. Northeast and East China regional grids are the first to set up their markets in 2004. The size of a regional market facilitates efficient competition. However,due to dif-ferences in economic development,significant parity exists today in neighboring provinces,which necessitates the adop-tion of different tariffs. Therefore,the provincial electricity market is allowed in some instances as an interim measure. In such a case,there will be a hierarchical market structure in which several provincial EDTCs are coordinated under a regional EDTC. But the goal is that eventually there is one EDTC per region. The EDTC is,in general,responsible for generation scheduling,contingency analysis,and congestion management. It also handles settlement and ancillary services (either self-provision or purchase).

The State Electricity Regulatory Commission was estab-lished in 2002 to ensure fair competition in the market. The commission is charged with the responsibilities to develop

36IEEE power & energy magazine july/august 2005

market rules,to monitor and to regulate market operation, and to maintain market efficiency. This is the first time in the history of China’s electric power industry a regulatory body has been set up.

Under the one-country-two-system rule,the special administrative regions of Hong Kong and Macau have their own power industry structures. The power companies in Hong Kong and Macau are privately owned and they operate like a regulated monopoly with franchised service territory: Hong Kong Electric in Hong Kong Island,China Light and Power in the rest of Hong Kong,and Companhia de Electri-cidade de Macau in Macau. The regulatory compact is a con-tract,called a scheme of control(SOC) in Hong Kong, between the government and the utility company. The terms of the SOC are pretty similar to a regulated monopoly,e.g., vertically integrated monopoly with an obligation to serve and guaranteed rate of return. The SOC in Hong Kong will not come up for renewal until 2008. But public consultations are already underway to discuss the shape of the future power industry in Hong Kong.

Electricity Market Challenges

The driving force behind deregulation in many Western coun-tries is the belief that competitive markets make the industry more efficient,leading to lower costs. In particular,under the rate-of-return regulation,electric utilities tend to overbuild causing higher cost to consumers. In the case of China,like other developing countries,the push for restructuring comes more from the needs for opening the electric generation mar-ket for private investment and to provide a leveled playing field for all participants. Of course,there is also the belief that the efficiency of a state-owned enterprise can be improved by private management.

From the beginning of its economic reform,China has been very mindful of the need for attracting nonstate capital to build the necessary power generation sector. A BOT (build-operate-transfer) scheme was adopted for power plant contracts. Long-term take-or-pay contracts with guaranteed price and minimum quantity of electricity on an annual basis were signed between the state or local governments and the builders of the power plants. These contracts tend to be very generous,and the annual return on investment generally exceeds 15%. A large number of IPPs were built with domes-tic or foreign capital from 1985–2000. During the excess-capacity period of the mid-1990s,some local governments were hard-pressed to honor these contracts. A proper balance between attractiveness to investors and affordability to con-sumers in the electricity business needs to be found as the economy matures.

In an ideal competitive electricity market,there is no central planning for generation expansion and market price signals are supposed to be enough to induce investors to

build power plants. There is no more guarantee on invest-

ment return,and it is up to the investors to assess expected

profit and risks. H owever,in the initial stage of market development,it is too risky to rely on this untested theoret-

ical approach to ensure adequate generation that is so essential for the well-being of the society. Various forms of capacity payment have been added in different countries as incentives for generation investment. Large swings between excess capacity and undercapacity have to be avoided for any power systems,especially so for fast-developing countries like China. The greatest challenge in

the restructuring of China’s power industry is to ensure that

the market rules send the right signals to ensure a proper

level of generation investment.

As a fast-developing country,China can ill-afford the economic consequences of the inadequate or oversupply of electricity. The official data indicates that the power short-

age in the coast province of Zhejiang alone for the first half

of 2004 cost billions of dollars as a result from the direct

loss in GDP. On the other hand,the market response to the

power shortage is swift. It is reported that there is as much

as 80 GW of unplanned capacity under construction from factories and other sources and,if true,that might result in oversupply in a few years’time and cause significant finan-

cial losses to investors.

In China,a two-part tariff is used,for example,in the northeast city of Liaoning The cost of electricity for resi-dential customers is around US 5.4 cents/kWh. For com-mercial and lighting it is around US 9.5 cents,and for industrial customers,in addition to the energy charge (between US 3.7–5.3 cents/kWh),there is the capacity charge,consisting of two parts,one is based on maximum demand (around US$2.68/kW per month) and the other is

based on transformer capacity (around US$1.83/kV A per month). Under the restructured system,the price of the energy will be determined by the electricity markets (con-

tracts and spot) described previously; the price of capacity payment is determined through a unique market mechanism

at the planning stage. First of all,generation planning will

be conducted by the grid companies,who determine the

The greatest challenge in the restructuring of China’s

power industry is to ensure that the market rules send

the right signals to ensure a proper level of generation investment.

july/august 2005IEEE power & energy magazine

optimal timing,size,location,and type of generation addi-tion. Investors of power plants then bid for the capacity pay-ment. In other words,the generator of the winning bid will then have the guaranteed income from the capacity payment plus the (uncertain) revenue for energy production that comes from contracts or the spot market. In this way,part of the risk of investment return is shifted from investors to consumers (capacity payment). At the same time,the com-petitive drive for efficiency improvement (competitive con-tract and spot markets) is still maintained.

Foreign investment in China’s power generation reached its peak in 1997 at 14.5% of the total fixed asset,from around 9.5% in previous years. As stated previously,generous risk-free long-term contracts were no longer signed with the intro-duction of competitive markets. The foreign investment has steadily declined to 7.5% in 2002. The latest indication from unofficial data seems to suggest that foreign investment is crawling back again as market rules are finally specified and become transparent.

Transmission planning in China is solely the responsibility of the grid companies. Traditional transmission planning practices have been followed; therefore,many new issues in transmission planning in the restructured environment do not seem to have surfaced.

Conclusion

In the last few years,China has reached several milestones in the development of electric energy systems:the Three Gorges project has started generating power,an intercon-nected national grid has formed,new environmental regula-tions have been enacted,and the industry has been fundamentally restructured. The scale,speed,and complexi-ty of the developments in both generation and transmission systems are breathtaking. And this promises to be just the beginning of a long and arduous endeavor.

The building of the electric energy supply infrastructure to power China’s economic developments is a colossal undertak-ing. Until now,China’s electric energy system has basically emulated the West. Technologies and solutions evolved gradu-ally in the West over decades of developments. In an industry with a large base of legacy facilities,a fast-growing system in China has emerged from a modest beginning. Continuing along the current path does not seem viable. If current fossil fuel generation technologies are used when the generation capacity doubles or triples,the cost to the environment and society will be hardly affordable. High-voltage transmission technology is hitting the limit. The applications of power elec-tronics and information technologies are not fast enough. China must develop its future electric energy system in a more efficient,more intelligent,and more sustainable manner than what has been done historically anywhere in the world. As the largest developer of an electric energy system,China has to take a leadership role in future technology R&D in all aspects, including clean energy development and efficient energy uti-lization with state-of-the-art power electronics and informa-tion technologies. Hopefully,China will be able to lead,not just in the deployment and utilization of electric energy sys-tems but also in the development of new technologies in the coming decade to benefit the nation and the world. Acknowledgments

The support from the National Key Basic Research Project (No. 2004CB217900),sponsored by the Ministry of Science and Technology of China,is gratefully appreciated.

For Further Reading

China Electricity Council,Electric Power in China 2004, China Electric Power Information Center.

State Power Information Network(in Chinese) [Online]. Available:https://www.wendangku.net/doc/da1147853.html,. cn/dlyw/default.htm W.Zhonghong,S.Fei,and W.Tiezheng,“FACTS applica-tions in China and its developing trends,”(in Chinese), Automation Electric Power Syst.,vol. 24,no. 23,pp. 1–5, 2004.

Y.Qixun,“Development trend of integrated protection and control in power substations,”(in Chinese),Proc. Chi-nese Soc. Elect. Eng.,vol. 16,no. 3,pp. 145–146,May 1996.

F.F.Wu,F.-L.Zheng,and F.-S.Wen,“Transmission invest-ment and expansion planning in restructured electricity market environment,”Energy J.,submitted for publication. Biographies

Felix F. Wu is an IEEE Fellow. He is the Philip Wong Wilson Wong Professor in Electrical Engineering at the University of Hong Kong,where he served as pro-vice-chancellor from 1997–2000,and is a Professor Emeritus at the University of California,Berkeley,where he has been on the faculty since 1974. He received his B.S. degree from National Taiwan Uni-versity,his M.S. degree from the University of Pittsburgh,and his Ph.D. degree from the University of California,Berkeley. He has served as a consultant to a number of industry and government agencies,including Pacific Gas and Electric Company,ABB-Systems Control,Electric Power Research Institute (USA),Statcraft Norway,Iberdrola Spain,etc.

Shuti Fu received his B.S. degree from the electrical engi-neering department at Tsinghua University,Beijing,China,in 1948. From 1949 to 1950 he took a graduate training course at the Allis-Chalmers Manufacturing Co.,Milwaukee,Wiscon-sin. He returned to China in 1951 and worked for the Central Laboratory of China,Electric Power Bureau,from 1951–1953,the North China Electric Power Design Institute from 1953–1971,and Hebei Electric Power Design Institute from 1972–1977. He was engaged in power system analysis and programming from 1962–1978. Since 1978,he joined China Electric Power Research Institute (CEPRI),Beijing, China,as a computer application engineer,specializing in power system online applications. From 1983–1985 he was the deputy chief engineer in CEPRI. Now he is presently a consultant (officially retired since 1994).

38IEEE power & energy magazine july/august 2005

p&e