Britain and China collaborate on carbon capture and storage

13 February 2009

British and Chinese scientists are working together to limit the environmental damage caused by China's increasing reliance on coal power.

Power station chimneys

Capturing the carbon given off by the Chinese energy industry is an essential step to controlling runaway human emissions and the climate change they cause, and a workshop in Britain aimed at addressing the issue finished yesterday.

It's thought China builds another coal-fired power station every week. Coal is the most polluting fossil fuel, so carbon capture and storage (CCS), as it's called, could be vital if the nation is to curb its CO2 emissions while maintaining its supply of energy. CCS involves capturing carbon dioxide at its source and stopping it getting into the atmosphere by burying it underground in rock formations and voids.

"As China builds more coal-fired power stations it is locking in CO2 emissions for 30, 40, 50 years to come," says Jonathan Pearce of the British Geological Survey (BGS). "It's very important we try to help the Chinese decide whether CCS is a possible route for them to deal with these emissions."

The conference took place in Nottingham, and is hosted by the BGS. Scientists discussed the findings of collaborative projects like Cooperation Action within Carbon Capture & Storage China-EU (COACH) and Near Zero Emissions from Coal (NZEC).

"COACH and NZEC look at the potential for geological storage of CO2 in parts of north-east China, where the coal power generation capacity is increasing at an amazing rate," says Dr Mike Stephenson, head of science for energy at BGS.

"The potential for storing CO2 in formations that contain naturally occurring brine, in old oil fields whose oil is depleted or used up, or in unmineable coals is being studied," he adds. The Chinese and EU experts have calculated the storage capacity of these formations and have discussed their results at this week's meeting.

A side-benefit of CCS in depleted oil and gas fields is that pumping in CO2 can help the energy industry extract residual deposits of fossil fuels that were previously inaccessible. The Chinese and European scientists have been carrying out research at two of the country's major oil fields, aiming to discover not only how much CO2 could be stored underground but how much extra oil could be produced at the same time.

The oil fields appear to offer relatively limited storage opportunities compared to areas such as the North Sea, offering only a few tens of millions of storage capacity, according to Pearce. But China's saline aquifers offer much more room for CO2 storage, he explains. "We know less about these, so we need to make a more theoretical estimate of their storage capacity," he explains.

"But they offer the potential for very large amounts of storage - between 70 and 700 gigatonnes over one particular region to the north of Beijing," he adds. "It's fair to say that any large-scale deployment of carbon capture and storage in China will have to use saline aquifers - as is also the case in Europe."

He explains that the oil fields will still be important, as the enhanced oil recovery enabled by CO2 storage will help offset some of the cost of CCS - an important consideration because of China's limited oil reserves. China already has a pilot project capturing CO2 from a coal-burning power station.

Experts have warned that it's vital to cut China's carbon emissions if we are to meet the goal of avoiding a temperature rise of 2°C by the end of the century - indeed, some argue that reductions elsewhere are essentially irrelevant unless China's emissions can be brought under control. Technology and scientific know-how from scientists in the west will be vital to achieving this.

As well as the possibility of sequestering carbon underground, the COACH programme is also investigating other clean energy technologies ranging from hydrogen production, synthetic fuels and coal gasification to the possibility of putting the heat created by burning fossil fuels to use in nearby industrial facilities, rather than simply pumping it into the atmosphere as steam as is usually the case at present.

BGS scientists are collaborating with researchers from the Chinese University of Petroleum in Beijing, the Chinese University of Petroleum in Huadong and the Institute of Geology & Geophysics of the Chinese Academy of Sciences.