Syngas: Trade Offs for Water & Air
By Tien Shiao, Tianyi Luo, William Hua Wen 7 November, 2013
WRI on how China's latest scheme to cut air pollution by replacing coal with syngas will exacerbate water stress
Record-setting levels of smog this week shut down Harbin, a city of 11 million people in northeast China. Officials blamed increased coal consumption during the first days of winter heating, underscoring the urgency of the China State Council’s recently announced initiative to address persistent smog in major cities.
While the Air Pollution Control Action Plan has ambitious goals—cutting air particulates and coal consumption—it may create unintended problems for the country’s water supply.
“Converting coal to natural gas, however, is an extremely water-intensive process. One cubic meter of SNG requires 6 to 10 litres of freshwater to produce.”
The Plan aims to reduce particulate matter in the North China Plain by 25% and reduce coal’s share of the national energy mix to 65% by 2017. One of the plan’s key recommendations is to replace coal with cleaner natural gas, including synthetic natural gas (Syngas/SNG) converted from coal. Converting coal to natural gas, however, is an extremely water-intensive process. One cubic metre of SNG requires 6 to 10 litres (1.58-2.6 gallons) of freshwater to produce.
So in an attempt to control urban air pollution in the east, China might jeopardize its water supplies elsewhere.
Using WRI’s Aqueduct Water Risk Atlas, we overlaid the locations of these approved SNG plants on our water stress maps to assess the potential water risks and found the following:
Chinese SNG Industry Faces High Water Risk
As of September 2013, the Chinese government approved 18 large-scale SNG plants with a total capacity of 75.1 billion m3 of natural gas per year (see table below for the full project list). SNG plants require water for cooling, production, and to remove contaminants post-production.
China’s proposed SNG plants, most of them located in arid and semi-arid regions in Xinjiang and Inner Mongolia, together will consume a total of 500 to 700 million m3 of freshwater annually at full operating capacity. That’s almost 20% of the region’s total industrial water use in 2011. The plants would therefore significantly exacerbate stress in areas already experiencing chronic water shortages.
In short, over 76% of the proposed SNG capacity will face high or extremely high baseline water stress, meaning each of the locations either competes with many other users for limited available water supplies, or has very little water available at all (see map below).
Exposure to Seasonal Variability
Eleven of the approved plants, eight from Xinjiang Province and three from Inner Mongolia are located in catchments that do not have major reservoirs. They also face medium to high or high risk from seasonal variability. So, in the dry season, those plants may have to reduce production capacity or experience temporary outages due to the lack of resilience in water supply (see map below).
Ordos Basin’s SNG plants can disrupt regional water security
Under a memorandum of understanding with the Inner Mongolia Government, Beijing will become the first Chinese city powered by SNG, receiving at least 4 billion m3 of SNG annually. This production would consume more than 32 billion litres of freshwater, enough to meet 1 million Inner Mongolians’ domestic needs for an entire year.
“Ordos’ 5 approved SNG plants will need ~140 million m3 of freshwater annually, which is ~10% of Ordos’ total water supply, or 40% of the region’s industrial water use as of 2011”
SNG development around the city of Ordos illustrates how these water-intensive plants can disrupt regional water security. In the middle of the Mu Us Desert, Ordos’ booming coal-to-gas bases face severe competition for water between domestic and industrial users.
Ordos’ five approved SNG plants will need approximately 140 million m3 of freshwater annually, which is around 10% of Ordos’ total water supply, or 40% of the region’s industrial water use as of 2011. Once these SNG plants are completed, they could further disrupt water supplies for farmers, herders and other industries.
SNG’s Other Environmental Implications
“While SNG emits fewer particulates into the air than burning coal, it releases significantly more greenhouse gas … life-cycle CO2 emmissions are 36-108% higher than coal”
While SNG emits fewer particulates into the air than burning coal, it releases significantly more greenhouse gas than mainstream fossil fuels.
Peer reviewed studies in the journal Energy Policy estimate that life-cycle CO2 emissions are 36–108 percent higher than coal when coal-based SNG is used for cooking, heating, and power generation. Rapidly deploying SNG projects might, therefore, be a step backward for China’s low-carbon energy strategy as well.
The government will have to decide whether alleviating air pollution from major cities in the North China Plain to more remote areas such as Inner Mongolia and Xinjiang – where most of the SNG plants are – is worth it. Additionally, since water risks will likely disrupt SNG production and new plants would further strain already stressed water resources, the national government must engage with the nation’s water authorities. The Ministry of Water Resources and Ministry of Environmental Protection are good places to start. Meanwhile, water authorities should consider tightening caps on industrial water withdrawal and water pollutant discharge or introducing stricter local environmental standards in high water-risk areas.
Over the long term, China should prioritize energy projects that face fewer environmental risks, especially from water and greenhouse gas emissions. Only then will China more successfully manage its conflict between economic growth and resource demands and find lasting energy security.
1 Zhu, R.C. Research on the SNG Technology. Coal Quality and Technology (China). 2011 (in Chinese)
- More Power to Enforcement – Environmental protection was a central theme of the recent Beijing Forum, here Debra Tan discusses how this along with recent policy developments seem to signal that China’s environmental protection legislation has grown some teeth and that she is firmly on the path to more enforcement
- Coal-to-Chemicals: Shenhua’s Water Grab – Greenpeace’s Calvin Quek explains why Shenhua’s coal-to-liquids plant in Inner Mongolia could be facing significant financial & environmental headwinds due to rising water risks
- Spend to Quench Coal Thirst – Can China manage to balance her limited water resources & coal expansion? Debra Tan argues that the sector can spend to quench coal thirst with consolidation or more investment in aggressive water savings tech
- Water for Coal: Thirsty Miners? – With up to 83% of China’s coal reserves in water stressed & scarce regions, the recent CLSA report asks if there is enough water to grow coal production. If not, what are our options? Debra Tan expands
- Is Fracking the Answer for Water Scarce China – Will water limit China’s access to possibly the world’s largest resoure of shale gas? Lisa Genasci discusses China’s possible energy alternative and its hold-backs
- Water: Shaping China’s Food & Energy Choices – Debra talks about key issues & new trends surfacing from the Fortune Global Forum roundtable and why she thinks the 12FYP Strategic Emerging Industries are the real Magnificent Seven
Read more from Tien Shiao →
Read more from Tianyi Luo →
Read more from William Hua Wen →