CHINA - Experts are voicing worries over plans to reduce coal combustion by using more natural gas as the heating season approaches.
The large number of coal power plants being refitted as gas power plants will increase nitric oxide emissions, Chinese Academy of Engineering academician Ni Weidou said.
"Natural gas should be used rationally, and coal-to-gas projects should be implemented cautiously," Ni said.
"Otherwise, more nitric dioxide will be discharged and pollute the air."
Ni made the remark at an international forum on air quality management in Beijing organised by the Energy Foundation on Saturday.
Coal's proportion of the energy mix should not exceed 65 per cent by 2017, when clean coal should account for at least 70 per cent of total coal use. The clean coal proportion is around 80 to 90 per cent in most developed countries.
The country will by then also have added more than 150 million cubic meters worth of natural gas pipeline-transportation capacity.
Ni said advanced technology enables clean coal to produce very low emissions. Nitric dioxide emissions are lower from all grades of coal compared with natural gas, he said.
"Considering more fuel is combusted in gas-fired combined heat and power boilers in order to get the same amount of heat, the nitric oxide emission is larger than that from coal-fired ones," he said.
Ni said the total emission of nitric dioxide will increase and the air quality will worsen if the four coal power plants in downtown Beijing are transformed into gas-fired CHP while contributing the same amount of heat.
Feng Yongfeng, founder of the Beijing-based environmental NGO Green Beagle, is also concerned about the burden placed on other cities to ensure Beijing's gas supply.
"The use of clean energy might burden neighbouring provinces and regions, and the government should not be unrealistically optimistic about the project," Feng said.