Clearing the city air in eastern China may see a water shortage in its western regions, according to a recent report.

One of the measures listed in the Air Pollution Control Action Plan from 2013 to 2017, released by the government on Sept 12, is to replace coal with cleaner natural gas, including synthetic natural gas converted from coal.

But "converting coal to natural gas is an extremely water-intensive process", said a report released by the World Resources Institute, a global research organization based in the United States, which studies climate, energy and water.

"It requires 6 to 10 cubic meters of fresh water to produce 1,000 cubic meters of coal-converted natural gas. So in an attempt to control urban air pollution in the east, China might jeopardize its water supplies elsewhere," it said.

Beijing and northeast China have often been shrouded in heavy smog and haze in recent years, prompting the government to roll out measures to improve air quality.

Energy from gas will play a major role in improving China's energy mix, Gao Shixian said at the Synthetic Natural Gas Strategic Development Forum in Chifeng, the Inner Mongolia autonomous region, in September.

Gao is a researcher from the Energy Research Institute of the National Development and Reform Commission.

About 20 synthetic natural gas projects have been approved by the government in 2013, most of which are located in the Xinjiang Uygur autonomous region and Inner Mongolia. Investment in this industry in the next three years may exceed 240 billion yuan ($39.4 billion), according to Shanghai Securities News.

But synthetic natural gas plants require water for cooling, production, and to remove post-production contaminants.

Proposed synthetic natural gas plants will consume 500 to 700 million cubic meters of fresh water annually at full capacity.

The plants will therefore significantly exacerbate stress in areas already experiencing chronic water shortages, the World Resources Institute report said.

Experts said the government has not neglected other ecological problems when trying to solve the air pollution.

"The action plan clearly stated a precondition to the development of synthetic natural gas, which is 'subject to the most stringent environmental requirements and the guarantee of water supplies'," said Wang Jian, deputy head of the pollution prevention and control department at the Ministry of Environmental Protection.

Li Gao, deputy head of the climate change department at the National Development and Reform Commission, said the precondition must be upheld.

While synthetic natural gas emits fewer particulates than burning coal, it releases significantly more greenhouse gases than mainstream fossil fuels, the World Resources Institute's report said.

Li said the government has been paying attention to this issue and is thinking of adopting the technology of carbon capture and storage to deal with the greenhouse gases emitted, but the technology itself has to be improved.

wuwencong@chinadaily.com.cn

(China Daily 11/02/2013 page4)