Patricia Adams & Grainne Ryder

November 30, 1998

Proponents of the Three Gorges Project claim that the megadam is the best way to reduce China’s reliance on coal.  Energy specialists argue, however, that switching from coal to gas, and using new technology of combined cycle gas turbines or cogeneration, would be able to reap greater environmental benefits than the Yangtze dam by a prospective 60 per cent reduction of carbon dioxide emissions.

The Three Gorges dam would reduce carbon dioxide emissions by 5 per cent.

Patricia Adams and Gráinne Ryder of Probe International state in an article which appears in the coming issue of International Journal (53/4, autumn 1998), that the most economical way to reduce coal consumption is through cogeneration. China has about 450,000 industrial, commercial, and residential-use boilers burning 400 million tons of coal per year, about eight times the amount of coal that Three Gorges might potentially displace. If one-quarter of the boilers were retrofitted for cogeneration with the same amount of fuel, they could expand electricity supply by 80-90 billion kilowatt-hours annually, roughly equivalent to Three Gorges’ expected output but at a fraction of its cost. Below is an excerpt of the second part of their article. – Editor

China leads the world in both coal production and consumption. About 40 per cent of its annual consumption is burned in conventional coal plants to generate electricity and 60 per cent in inefficient boilers and furnaces to meet industrial and municipal demands for heat and steam. According to a study by the Battelle Memorial Institute – a Washington-based energy policy think-tank – the Beijing Energy Efficiency Center, and China’s Energy Research Institute, "no other major economy relies so heavily on coal to meet its primary energy needs." The environmental damage across the country is extensive. Energy experts calculate that sulfur dioxide emissions, the main cause of acid rain, cost over $13 billion each year in damage to forests, farms, and public health, and erase two per cent of the country’s gross national product. Poor air quality also leads to millions of premature deaths and illnesses.

Proponents claim the Three Gorges dam is the best way to reduce China’s reliance on coal. In fact, the dam would reduce coal burning at most by about three per cent and total carbon dioxide emissions from heat and electricity generating facilities by about 5 per cent. Switching from coal to gas, and using either combined cycle gas turbines or cogeneration, would provide greater environmental benefits than Three Gorges by reducing carbon dioxide emissions by more than 60 per cent.

The cheapest way to reduce coal consumption, according to researchers at the Lawrence Berkeley Laboratory at the University of California, is through cogeneration. The researchers found that about 400 million tons of coal per year is burned in 450,000 industrial, commercial, and residential-use boilers, or about eight times the amount of coal potentially displaced by Three Gorges. If just one-quarter of the boilers were retrofitted for cogeneration, with the same amount of fuel they could expand electricity supply by 80-90 billion kilowatt-hours annually, equivalent to Three Gorges’ expected output, but at a fraction of Three Gorges’ cost.

They also found vast untapped potential for cogeneration in the iron and steel, chemical, paper, rubber, textile, and printing and dyeing industries, with capital costs well under $1200 per kilowatt. In the chemical fertilizer industry, for example, approximately 55 billion kilowatt-hours of electricity could be generated by retrofitting half the existing plants for cogeneration. And if 500 towns and cities installed small-scale cogeneration systems, they could generate about 50 to 60 billion kilowatt-hours of electricity – about two-thirds the Three Gorges output – which is sufficient to meet their year-round heating and cooling requirements.

The benefits of replacing inefficient power plants, boilers, and furnaces with coal-fired cogeneration systems are well known in China, even though their commercial use is underdeveloped compared to other countries. The Lawrence Berkeley researchers found that one coal-fired cogeneration plant in Jingzhou, Liaoning Province, not only alleviated power shortages but also eliminated the need for 115 small coal-fired boilers and reduced sulphur dioxide and particulate concentrations in the area by 32 per cent and 48 per cent respectively. Less coal consumption means that less coal has to be mined and washed, which has the added benefit of reduced soil erosion and water pollution.

In China’s northern region, the central government has built about 3700 MW of cogeneration plants to provide electricity and steam to industrial consumers and space heating for local residents. In the last five years, the giant Huaneng Power Generation Corporation has built three large-scale cogeneration plants in the north and is building a 300-MW cogeneration plant near Beijing. In the country’s industrial sector, cogeneration plants over 100 MW are typically found in petroleum refineries, large chemical plants, food processing plants, and district heating systems. Medium-scale plants – between 25 and 100 MW – power sugar mills and industrial parks. Plants producing 25 MW or less are found in the chemical, textile, and paper industries.

Approximately 11 per cent of China’s thermal power plants (that is, coal, oil, gas, and nuclear) are equipped for cogeneration. The government estimates that an additional 40,000 MW of existing coal plants could be retrofitted for cogeneration. In terms of capital cost, old coal plants and boilers can be retrofitted for cogeneration for about two-thirds of the cost of building new power plants because their construction time is shorter and they require less initial capital. The government has already ordered retrofits or shut downs for the worst polluters and the most inefficient coal plants. But many upgrade projects have had to be stopped for a lack of funding. Private investors have been reluctant to invest in cogeneration because electricity and heat prices are low, conflicts with monopolistic utilities abound, and the levies are high (for grid connections, back-up power, Three Gorges construction).

Three Gorges Probe welcomes submissions. However, it is not a forum for political debate. Rather, Three Gorges Probe is dedicated to covering the scientific, technical, economic, social, and environmental ramifications of completing the Three Gorges Project, as well as the alternatives to the dam.

Publisher: Patricia Adams Executive Editor: Mu Lan ISSN 1481-0913