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Recycling Waste Coal for Power Generation in China

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Recycling Waste Coal for Power Generation in China

June 7, 2023 nflg 0 Comments

People’s Republic of China: Recycling Waste Coal for Power Generation

1. During the December 2008 country programming mission of the Asian Development Bank (ADB), the Government of the People’s Republic of China (PRC) requested technical assistance (TA)1 to study recycling waste coal for power generation at the Pingshuo coal mine in Shanxi Province. ADB conducted a fact-finding mission from 4–5 June 2009 and reached an understanding with the Shanxi provincial government on the TA’s objective, scope, cost estimates, financing plan, implementation arrangements, and consultants’ terms of reference. The design and monitoring framework is in Appendix 1.

2. In 2008, coal-fired power stations generated 81% of total 2,779.3 terawatt-hour (TWh) electricity in PRC.2 The power sector consumed 1.3 billion tons of raw coal, or about 50% of total coal produced in PRC.3 Every year, waste coal is generated during coal production as the largest solid waste discharged by industry, accounting for about 25% of industrial solid waste. Its large stockpiles damage mining areas’ ecology and occupy valuable land. In addition, spontaneous combustion within these heaps causes air pollution and safety hazards, and leaching of trace elements with rainwater causes groundwater contamination.

3. Currently, annual waste coal generation in PRC is around 200 million tons, which is almost equivalent to the coal production in the Russian Federation, the sixth-largest coal producer in the world. Accumulated waste coal in PRC was about 4.5 billion tons in 2008. Shanxi Province, the largest coal-producing province, has accumulated about 1.1 billion tons of waste coal, and its annual waste coal production is around 100 million tons.4 The utilization level of waste coal in Shanxi Province is only 50%, so environmental issues related to waste coal are more acute here than in other provinces. Although waste coal use for power generation has been increasing due to government policies, technical and regulatory barriers still exist, which may delay or impede large-scale waste coal use.

4. The 11th Five-Year Plan (FYP) for Energy Development in PRC requires that waste coal use should increase to 390 million tons in 2010 from 150 million tons in 2005. Both the 11th FYP for Economic and Social Development and 11th FYP for Energy Development emphasize building large-scale circulating fluidized bed combustion (CFBC) boilers to control pollution from waste coal heaps. According to the State Council’s Opinion on Accelerating Development of a Recycling Economy and Shanxi Recycling Economy Development Plan under the 11th FYP, there is an urgent need to develop the integrated use of waste coal from coal production for thermal power-generation.

5. In 2004, ADB provided a TA to promote waste coal use in Shanxi Province.5 The resulting study was completed in November 2006, and its main recommendations included promoting waste coal power generation and further study to determine the techno-economic feasibility for large-scale (i.e., 600 MW and higher) waste coal power generation plants.

6. In the mid-1980s, waste coal power plants were established in PRC in sets of 6 MW. By 2004, more than 200 waste coal power plants were built with an aggregate capacity of 4 gigawatts (GW), utilizing 40 million tons of waste coal to produce 24 TWh of electricity annually. The largest plant, however, is only 300 MW. Looking ahead, to utilize even 50% of annual waste coal (i.e., 150 million tons), a total capacity of 45 GW is needed. Therefore, more power plants are required—located at every large coal mine—that have the largest capacity that is technically possible. When the unit size is large, it is cost-effective to include designs that control pollution, comply with national emission standards, and enable higher efficiency to increase financial returns and reduce carbon dioxide emissions. Moreover, new emission standards of air pollutants for thermal power plants (GB13223-2003) stipulate stricter emission standards for waste coal power plants, and only large waste coal power plants of about 600 MW range can achieve them.6

7. Most modern coal-based power plants use (i) pulverized coal combustion (PCC), in which coal is finely ground so it can burn efficiently, and (ii) supercritical and ultra-supercritical steam parameters. The most efficient units convert 42%–45% of the heat in coal to electricity.7 The main drawbacks of PCC coal-based power plants are that their transformation and pollution control efficiencies are sensitive to changes in coal quality, the cost of pollution control equipment is high, and waste coal cannot be used efficiently because of variations in quality. Supercritical and ultra-supercritical coal-based power plants also require superior grade steel tubes, which result in higher boiler costs. Therefore, the appropriate design is CFBC. Although development of CFBC technology has been slow (presently, only 2% of the world’s coal-based power plants use it), it is particularly suited for coal with lower heat content and high sulfur. The efficiency of its large-sized units (i.e., over 300 MW) can be similar to that of PCC units.

8. Although national policies encourage waste coal power plants, the policies can be improved to simplify exemptions and reductions in income and value-added taxes for power generated from waste coal power plants. The State Council stipulates that such power plants should get preference in selling power and the power sale price; power plants with capacities of 12 MW or less are exempted from the grid load management and related fees.8 Still, coal mining companies and other power producers face obstacles in selling power to grids. Various fees are involved in power sale transactions,9 and there is a lack of a transparent and fair structure.

Presently, the power generated by waste coal power plants can only be purchased by provincial power distributing companies, which are wholly owned subsidiaries of just two national grid companies.10 A prolonged and laborious process in negotiating power sales agreements with off-takers is also a serious barrier.

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