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A breath of fresh air

Hydrocarbon Engineering,


China is the world’s second largest economy and the biggest energy-using nation in the world. It is a major emitter both of greenhouse gases (GHGs) and of SO2, NOx and fine particulates, arising in part from the massive use of coal in the power generation sector. Even with the Government’s ambitious plans to move to a less carbon-intensive economy, coal will continue to dominate the energy mix and will continue to drive economic growth for the foreseeable future. The China Electricity Council has made several projections of future power capacity and use. It suggests that power consumption will increase from 4.17 trillion kWh in 2010 to reach 6.27 trillion kWh by 2015 and about 8 trillion kWh in 2020. In terms of total power generation capacity, that is expected to increase to about 1885 GWe by 2020, with about 64% based on fossil fuel technology, predominantly coal. 

These significant and continuing increases in coal use, especially for power generation, have caused severe air pollution problems, especially in urban areas. There are acid rain problems across large regions of southern China, while in cities throughout the country, the air pollution levels are high, with 90% of those assessed failing to meet World Health Organisation (WHO) health-based standards. The combined health and non-health cost of outdoor air and water pollution for China’s economy has been estimated by the World Bank and the former State Environmental Protection Administration (now the Ministry of Environmental Protection) to be some US$ 100 billion/year. There is also increasing concern being voiced in the national media, which notes that quality of life is an important factor to be considered and that growth at all costs should no longer be considered an acceptable way forward.

As a consequence, and following various assessments of the pollution challenges, the Chinese Government has made addressing such problems a key environmental priority, with the intention to accelerate the development of systems, institutions and a technical knowledge base for sustained air quality improvements. This includes the application of methods to:

  • Ensure central and local co-ordination of all initiatives, including the introduction of incentives for local Governments and firms to embrace clean energy.
  • Implement realistic levies, taxation and pricing to ensure appropriate use of emissions control devices.
  • Introduce effective supervision mechanisms.
  • Demonstrate that targets are a national Government leadership priority.
  • Ensure better co-operation between ministries to alleviate conflicting priorities of economic growth and environmental protection.

Coal industry emissions

A major focus is on the coal-fired power sector. New standards have been introduced from the start of 2012 that require modern, very high efficiency SO2, NOx and particulates emissions control systems to be installed, for which the likely combination of technologies for a modern coal-fired power plant is given in Figure 1.

Figure 1. Coal-fired power plant layout showing ESP, FGD and SCR system locations.

 

At the same time, there are increasing efforts to improve the technologies for the production of iron and steel, chemicals and building materials, which also consume large amounts of coal and represent large emission sources. In addition, having learned from its experiences during the 11th Five Year Plan period, the Ministry of Environmental Protection is taking the various initiatives further, to ensure effective monitoring, verification and control, such that acceptable implementation and compliance can be achieved within these sectors.

The nine key regions in China facing very significant air quality challenges are the three major economic zones around the cities of Beijing, Shanghai and Guangzhou, together with land areas around the cities of Shenyang, Chengdu-Chongqing, Changsha, Wuhan, the Shandong peninsula and the coastal area west of the Taiwan strait. These regions comprise the population and economic centres of the country, accounting for 64% of national GDP, 43% of total energy use and 39% of the population. In these locations, as shown in Table 1, all existing and new coal-fired power plants will have to achieve particulate, SO2 and NOx emissions limits of 20, 50 and 100 mg/m3 respectively, with new plants expected to meet the standards from 1 January 2012 and existing plants by 1 July 2014.  At the same time, there will be an increasing emphasis on limiting any new coal-fired power plants in these regions.

For the rest of the country the standards are not quite so strict, with the limits for particulates and NOx emissions for all plants being 30 and 100 mg/m3 respectively. For SO2, emissions must not exceed 100 or 200 mg/m3, depending on whether the plant is new or already in operation. In addition, in several provinces that are not so developed and that depend on the use of local higher sulfur coal, the SO2 limits are further relaxed. On a national basis, but excluding the nine priority regions, there is also a pragmatic acceptance that certain types of existing power plants, as well as those burning very low volatile content coals, will not be able to achieve the NOx levels expected elsewhere. Consequently, for those existing plants, these limits have been relaxed.

The new pollutant that will be regulated at coal-fired power plants is mercury and its compounds, for which the limit has been set at a level that represents a core control. This means that, providing the power plant operator meets the new particulate, SO2 and NOx standards, then the mercury standard, should be met without the need to introduce an additional capture device, although the emissions level will have to be measured on a regular basis.

New standards

Alongside these actions, the Government is beginning to address the need to establish more meaningful ambient air quality indices, including the need to address further pollutants of concern, such as the release of PM2.5. Consequently, while the new standards for the coal-fired power sector represent a very significant limitation of the emissions limits, there is an expectation that the improvement of the indices is going to lead to a further tightening of standards before 2020.

From a global perspective, this major Chinese environmental initiative will lead to a fundamental shift in the market for power plant air pollution control systems and services, both for new and retrofit/upgrade applications. In particular, Chinese coal-fired power capacity in 2010 was just under 700 GWe. By 2020, it will be at least 960 GWe, possibly 1065 GWe as there is inevitably some uncertainty in the future growth of this sector. On a conservative basis, for flue gas desulfurisation (FGD) systems, in the decade up to end 2010, China had installed FGD on close to 590 GWe coal-fired power capacity and so by 2020 this could rise to at least 960 GWe. To put this in context, for the rest of the world, the total installed capacity is some 380 GWe on coal-fired power plants since 1980. China also expects to install selective catalytic reduction (SCR) on all coal-fired power plant capacity by the end of 2020. The rest of the world has installed about 300 GWe of SCR systems since 1980.

In these situations, China’s demand will dominate the global markets. Costs over the next decade will rise due to Chinese demand for resources outstripping global supply, leading to overall shortages in materials for components (e.g. catalysts for deNOx and a wide range of components for FGD). However, in the longer term, when the enormous need for advanced pollution control systems on the Chinese coal fleet has been met, there will be some major Chinese suppliers entering the global market, which will decrease prices. Chinese companies are already the world’s leading suppliers of electrostatic precipitators (ESP), while another 10 Chinese companies are among the 20 largest FGD suppliers.

Conclusion

China is battling with the need to balance medium to longer-term strategic environmental objectives with finding solutions to short-term difficulties. Its approach is a pragmatic but ambitious one, with the need to address various interrelated challenges within the coal sector. It is important to recognise that the tightening of emissions standards and overall pollutant limits in the power sector is but one part of a bigger and longer-term effort by the national Government to establish energy efficient and environment-friendly industries across all the traditional energy intensive sectors. This already includes the compulsory introduction of certain advanced power generation technologies (e.g. with supercritical and ultra-supercritical steam conditions), and mandatory closures of small inefficient units. This is complemented by the use of economic incentives such as pollution levies and higher prices for electricity from the larger, more efficient power plants, as well as enhancements to such prices for electricity from units with satisfactory FGD operation.

The Ministry of Environmental Protection has undertaken some studies to ascertain the benefits to the national economy of improving air quality through tighter emissions standards and related measures within the various energy intensive sectors. Although the detailed results are not available, it is understood that the cost-benefit ratio is significant. That said, it is the power companies that will have to make these very significant investments to improve the environmental performance of their various coal-fired power plants.  These companies have been registering operational losses due to distortions from a market-based coal price and a power price that is capped by the Government. Therefore, this investment programme will represent a major dislocation within the national economy, and it remains to be seen how readily China can achieve these ambitious strategic environmental objectives while ensuring overall economic competitiveness.

This article is based on a report prepared by Dr Andrew Minchener OBE, for the International Energy Agency’s Clean Coal Centre: “Non-greenhouse gas emissions from coal-fired power plants in China”, CCC/196. It is available from www.iea-coal.org

Read the article online at: https://www.hydrocarbonengineering.com/special-reports/15022013/reducing_non_ghg_emissions_in_chinese_coal_fired_power_plants-008/


 

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