New capacity in Asia will be supplied from a variety of resources
In addition to the construction of new power plants, Asian electric utilities are upgrading and repowering their older, less efficient plants
By Douglas J. Smith
With a million MW of new capacity needed between now and the 2010, Asia will continue to be the world`s largest purchaser of power generation equipment in the world. Although the market is huge, the competition for supplying this equipment is tough and the risks can be high. Dominating the market for new capacity will be China, Korea, Taiwan and the southeast Asian countries of Indonesia, Malaysia, Thailand and the Philippines. Pakistan and India will also be major markets for the construction and/or upgrading of power plants. Figure 1 shows the growth and expected capacity requirements for Asia from 1985 through 2010.
To supply the increased capacity, Asia will use a variety of fuels and technologies, including combined-cycle gas turbines, pulverized coal-fired units, hydroelectric, pumped storage, diesels and nuclear power. However, many of the plants in operation will be repowered, upgraded and/or modernized to make them more efficient. The upgraded plants will also be more reliable and their capacity will be increased.
World`s largest market
There is no doubt that the largest market for power plant equipment over the next 10 to15 years will be China. With the aim of increasing its current capacity of approximately 250,000 MW to more than 500,000 MW by 2010, China will certainly need to purchase some of the new equipment from other countries. By 2010 thermal power will account for 74 percent of the total installed capacity in China. The remaining capacity will be 23 percent hydropower and 3 percent nuclear power. It is estimated that between now and 2010 China will account for almost 25 percent of the world`s energy demand and 50 percent of the global demand for coal.
One US company, Foster Wheeler International Inc. (FWEI), recently was awarded a contract by the China Electric Power Technology Import/Export Corp. to supply six 350 MW steam generators and auxiliary equipment for the Yangcheng No. 1 power plant. According to FWEI, the Yangcheng project is an independent power project that is to be constructed in China`s Shanxi province.
David J. Parham, FWEI`s regional vice president in China, says that the company currently has 7,300 MW of new capacity under contract with China. These range from 50 MW circulating fluidized-bed units to 660 MW utility boilers.
The Yangcheng steam generators will fire low-volatile anthracite coal from a nearby mine. This plant is reported to be the first mine mouth electric power plant in China. Although the plant is being constructed in the Shanxi province, the electricity will be carried by transmission lines to Jiangsu province. Commercial operation of the first steam generators is scheduled for late 1999 with each of the other units going into service at successive five month intervals.
During 1995 China, in order to speed up it extensive power plant construction program, launched the so-called “Laibin B” model with the condition that all financing had to come from foreign sources. The end result was a build-operate-transfer agreement. At the end of 1995, the Guangxi province government issued a pre-qualification call for investors to build, finance and operate the Laibin B 700 MW coal-fired power plant.
After pre-qualifying 30 companies, the Chinese arranged an on-site visit followed by an in-depth, question-and-answer session. Following this, six of the companies submitted bids, and on Oct. 15, 1996, GEC Alsthom and Electricité de France (EDF), which together submitted a joint bid, were named the preferred bidder. The final agreement was signed on Nov. 11, 1996.
Under the agreement a consortium made up of EDF-CNET and GEC Alsthom will have the responsibility for constructing the plant. Members of the consortium will supply and install the boilers, turbines, electrical equipment, instrumentation and controls systems, the substation and the balance of plant, a pumping station and auxiliary equipment.
A joint venture of EDF and GEC Alsthom Infrastructure Group has been formed to finance, build and operate the plant for 15 years. The joint venture company is 60 percent owned by EDF and 40 percent by GEC Alsthom. An international bank is providing the loan. Part of the loan is being guaranteed by Coface, a French credit insurance organization.
When the Korea Electric Power Corp. (KEPCO) was established in 1961, the total installed capacity in South Korea was only 367 MW. Electric generation at that time was principally supplied by anthracite coal-fired plants and hydropower. However, because of its relatively low cost, oil became the fuel of choice and by 1977 accounted for 89.35 percent of the total electricity generated. After the oil crisis of 1974, the Korean government and KEPCO`s strategy shifted to nuclear power. Today the total installed electric capacity in Korea is greater than 32,000 MW with nuclear providing 26.8 percent of the total capacity. Coal is the second largest fuel for power plants accounting for 21.1 percent followed by combined-cycle power 19.2 percent, heavy oil 14.5 percent and hydro 9.6 percent. Figure 2 shows the generation of Korean electricity by fuel type from 1961 through 2001.
The first nuclear power plant went into commercial operation in 1978 and by the end of 1995, 10 nuclear power plants were in commercial operation. Nuclear power continues to be constructed in Korea and for the foreseeable future will continue to supply the majority of electricity generated in the country. Table 1 shows the nuclear power plants under construction in Korea.
In 1996 KEPCO began the construction of 21 hydro and thermal power plants with a total capacity of 16,063 MW (Table 2). Construction of Yang Yang pumped storage plant, Bo Ryong combined-cycle plant and the coal-fired Dong Hae Unit 2 was started in the first half of 1996. Taean (Tae Ahn) Units 3 and 4, both 500 MW coal-fired plants, will enter commercial service this year. North Je Ju, an internal combustion unit, will also go into service this year and will supply electricity to the island Je Ju. Other work in progress includes the 100 MW Il San, 1,200 MW Seo In Chon Units 3 and 4, the 600 MW Ul San Unit 2 and the 35 MW Han Lim combined-cycle power plants.
500 MW standardized coal-fired units
As a way to further reduce the use of oil for the generation of electricity, KEPCO plans to construct 14,000 MW of coal-fired capacity by 2006 (Figure 3). However, to optimize the construction and reduce construction time, KEPCO is using a high degree of standardization in the design and construction of these new power plants. According to ABB Combustion Engineering project manager Jerry Moskal, the standardized design calls for 500 MW units with supercritical steam cycles for high thermal efficiency and sliding pressure steam generators for heavy cycling and two shift daily start-stop operation.
It is anticipated that at least 20 plants will use this standardized design at five sites in various parts of Korea. Currently KEPCO has placed six of these units into commercial operation. Another 14 units are under construction or in the initial stages of commissioning. The first 20 units with a combined capacity of 10,000 MW are scheduled for service no later than the year 2000.
The boilers, turbine-generators and turbine bypass systems are standard for all of the Korean plants. However, for economic reasons the balance-of-plant equipment is supplied by various vendors. In addition, because of the speed in which distributed control systems technology is changing, the plants will be fitted with state-of-the-art control systems. As a consequence, the control systems will not be standard.
A task force was set up in 1986 to prepare the bid specifications for the boiler and the turbine-generators. To help in this task, KEPCO selected Korea Power Engineering Co. as the architect-engineer and Burns & Roe as the technical consultant. Hanjung (formerly Korea Heavy Industries and Construction Company Ltd.) was selected as the prime contractor for the manufacture and supply of the major equipment.
Because KEPCO wanted the most advanced technologies and design for the boiler and steam generator, these items were put out to competitive bid. In December 1988 CE/Sulzer and GE were awarded the contracts for the supply of the boiler and turbine-generator respectively. Poryong Units 3, 4, 5 and 6 were the first standard units constructed and put into operation. All four units were completed in less than four years–August 1990 through April 1994.
The second plant to be designed with standard units was Taean. Units 1 and 2 were put into commercial operation in December 1995, two months ahead of schedule. Experience gained from the Poryong units was used to improve the design, construction and startup of the Taean units. As a result, many of the problems experienced at the Poryong plant were eliminated. According to KEPCO, the Taean units are now the standard design and all of the other units will be designed and constructed using Taean as the standard.
Environmental concerns in the construction of new power plants are always a problem and the Korean Taean project was no exception. However, the plant was designed to be environmentally friendly and pleasing to the eye. To make the plant more aesthetically pleasing, the boilers, turbines, flue gas stacks and other structures have been painted so as to blend in with surroundings.
High-efficiency electrostatic precipitators and an ash collection system have been installed to collect the fly ash. Emissions of SOx are controlled by flue gas desulfurization scrubbers. In addition, deep-sea cooling water intakes and discharges will minimize the adverse effect of warm-water discharges. Plans also call for the construction of warm-water fish farms which will help the local fishing community. Long term, plans call for opening the facility as a park. Table 3 summarizes the schedule for the remaining 500 MW standard coal-fired units. However, because of the expanding need for more capacity in Korea, KEPCO is reviewing the possibility of constructing a new 800 MW class of coal-fired units with supercritical steam cycles.
Heavy fuel oil at Chinese combined-cycle plant
Zhenhai combined-cycle power plant is under construction in the Zhendai district of Ningbo City in Zheijiang province of the People`s Republic of China. The plant, on the coast about 100 km south of Shanghai, is adjacent to an existing coal-fired power station. John Brown Engineering Ltd., now Kvaerner Energy Ltd. of Scotland, was awarded a contract by Zhenhai United Power Co. for the supply of the combined-cycle equipment.
The plant has been designed with two GE MS9001 Frame 9 heavy duty gas turbines, two heat recovery steam generators (HRSGs) supplied by NEM of The Netherlands, and a GEC Alsthom steam turbine. A bypass damper allows the gas turbines to operate in simple cycle should any of the HRSGs or the steam turbine be out of service.
Kvaerner says that the plant has been designed to operate on a two-shift basis with daily startup and shut down. When operating in combined-cycle mode the plant will produce 328 MW (ISO) at a thermal efficiency of 47.72 percent (Table 4). A single-stage filtration system, incorporating a reverse-flow compressed-air, self-cleaning system, supplies air to the gas turbines. On entering the gas turbine, the air passes through the inlet plenum and then, via the inlet guide, vanes into the 17-stage axial flow compressor. The inlet guide vanes are a row of variable pitch stator blades that assist in limiting the air flow to the gas turbines during startup. They also improve the efficiency of the units during heat recovery operation.
What is unique about the Zhenhai plant is the gas turbines will operate on heavy fuel oil. This fuel was chosen over natural gas and distillate oil because it is more available than natural gas and is lower in cost than distillate oil. However, heavy fuel oil does have some operational difficulties due to vanadium, sodium, potassium and carbon residues being inherent in the fuel. Although not the most ideal fuel for gas turbines, heavy fuel oil can be fired in gas turbines if it is first treated. At the Zhenhai combined-cycle plant, a fuel oil treatment plant (FOTP) is being installed. When operational the FOTP will have the capacity to treat 66 m3/hr, which is sufficient to operate both gas turbines at full load.
To prevent the formation of stable emulsions of wash water with the untreated heavy fuel oil, a liquid demulsifier is continuously injected prior to its being heated. After being heated, the heavy oil is mixed with hot water to further dilute and separate the water-soluble metallic contaminants, sodium, potassium and to a lesser extent calcium. These materials, in the form of a salt water solution, are separated by two-stage centrifuges.
After being centrifuged the fuel is heated, filtered, metered and a vanadium inhibitor added (Figure 4). Heating of the fuel is needed in order to achieve the correct viscosity prior to it being injected into the gas turbines. Distillate oil is used during startup and shut down of the gas turbines, thus eliminating the risk of any heavy fuel oil solidifying in the fuel lines when cold. Because the use of heavy fuel oil causes harmful deposits to build up the gas turbine, the efficiency of the turbines decreases over time. To remove these deposits, the gas turbines must be washed on a regular basis to remove any deposits. The washing is done with the units off-line.
According to Kvaerner Energy, the plant is being constructed in phases. Currently, the schedule calls for the plant to be in commercial operation by February 1998. The first phase was completed in May of this year.
Hong Kong`s Black Point station
China Light & Power Co. (CLP) is currently adding 2,500 MW to its generating capacity at its Black Point power station in Hong Kong. This capacity is being supplied by eight combined-cycle units.
The first two combined-cycle units went into operation in 1996, and two more units are scheduled for commercial operation in 1997. When completed the plant will be one of the largest gas-fired combined-cycle plants in the world. Black Point is owned by Castle Peak Power Company Ltd. and is a joint venture between Exxon Energy and CLP.
A consortium of GEC Alsthom and GE Power systems of the US is designing and supplying the power generating and ancillary equipment for the Black Point project. Each of the combined-cycle units includes a MS9001FA gas turbine, steam turbine and generator. The gas turbines are being supplied by GE and GEC Alsthom`s European Gas Turbine division.
Because of the anticipated need for additional capacity over the next several years, the Black Point site has been designed to allow expansion to 6,000 MW.
Zhenhai combined-cycle power plant under construction, People`s Republic of China. Photo courtesy of Kvaerner Energy, Scotland.