China pushes CO2 capture, storage questions loom

By Emma Graham-Harrison - Analysis

BEIJING (Reuters) - China is pushing to complete its first commercial-scale power plant that can capture and store emissions, but must do more research on how and where to lock away carbon dioxide if the technology is to get wide roll-out.

Pressure is building on the world's top emitter of greenhouse gas to curb the growth of its carbon dioxide (CO2) output. China itself is also worried about the impact of rising world temperatures on its climate and food output.

But coal is China's most plentiful domestic source of energy, and Beijing hopes for several more decades of rapid economic growth to lift millions from poverty.

That means capturing and storing carbon dioxide -- the main greenhouse gas blamed for global warming -- in underground reservoirs is likely to be crucial to containing emissions.

But officials worry about the expense and the environmental impact of the process.

"There are still a number of outstanding issues in relation to this technology," said Ma Yanhe, Director-General of the Chinese Ministry of Science and Technology. "Apart from reducing greenhouse gas emissions, it is not making very significant contributions to sustainable development.

"The technology itself is also energy intensive and the significant energy consumption is quite worrisome. Finally, there is no reliable assessment methodology for the long-term environmental impact of this technology."

Among the considerable obstacles facing scientists is uncertainty about how best to store CO2.

If there were problems with storage and large amounts of gas were released at once, perhaps in an earthquake, it could kill people at the surface, while leaks would void the expected contribution to fighting climate change.

Work has already begun on the first stage of the power project, a high-tech plant near the port city of Tianjin that will eventually strip CO2 out of gasified coal before combustion, but will run first for several years as a cleaner power station.

"We plan to start construction in 2014 and complete the works and start operations in 2016," Su Wenbin, head of China Huaneng Group's Greengen zero-emissions project, told a recent CCS conference.

Greengen also has a demonstration plant in Beijing where some of the gas stripped out is used to carbonate soft drinks.

CHINA'S OPTIONS

China's storage needs will be vast if it decides to push sequestration as a key part of efforts to curb emissions.

A 1 gigawatt (GW) power plant with a 40-year life span will generate about 200 million tonnes of carbon dioxide, according to a recent study by the China-Britain Near-Zero Emissions Coal initiative (NZEC), which is exploring China's CCS options.