BEIJING — Finding a way to corral and store carbon dioxide emissions, rather than vent those into the atmosphere, is considered among the most important strategies for limiting coal’s contribution to climate change.
Yet that technology is expensive, and requires substantial amounts of additional energy to separate, compress and pump carbon to storage sites.
The United States and the European Union nations have been slow to move forward with large-scale carbon capture.
So has China, where development lags far behind the pace once proposed by the International Energy Agency.
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China’s developers of demonstration projects have a deep understanding of the technology, said Lin Gao, a Chinese National Academy of Sciences researcher who is helping develop a carbon capture road-map for China. But some have concluded that, without scientific breakthroughs, the technology is unacceptable,
“Not only for the energy penalties but for the costs,” Gao said.
Still, carbon-capture proponents are hopeful Chinese leaders will shoulder such burdens to help limit climate change.
“We have to give this a shot,” said Armond Cohen, executive director of the Clean Air Task Force, which is working to spread the technology in China. “Until we scale up carbon capture and storage, China’s coal trends will continue to be an unmitigated climate disaster.”
Carbon storage effort
China’s biggest effort to pump carbon dioxide into the ground for long-term storage is under way in Inner Mongolia.
The Shenhua Group, a state-owned coal company, is pumping up to 100,000 metric tons a year of carbon dioxide into geological formations. That’s less than 6 percent of the carbon emissions from the Shenhua complex that turns coal into liquid fuels and chemicals.
That storage effort got an early assist from the U.S. government, which made recommendations on design of the project. But this project is unlikely to be replicated on a large scale.
That’s because the Chinese government’s first priority is to try to find a way to gain some value from the carbon dioxide, rather than just storing it underground.
In recent years, Chinese scientists have experimented with using carbon dioxide to produce fertilizers, plastics, biofuels and other products.
The oil industry offers the biggest potential market.
Pumping carbon dioxide into oil fields can boost production by reducing the viscosity of the crude so it can be pumped to the surface. There also can be a climate benefit because some carbon dioxide ends up trapped underground.
The oil industry will be taking the carbon dioxide emissions from GreenGen, China’s most ambitious effort to develop a coal plant that will not contribute to climate change.
This 400-megawattt power plant built near the port city of Tianjin is designed to separate the carbon dioxide before coal is combusted. By 2020, GreenGen is supposed to be piping most of its carbon emissions to offshore oil fields
So far, the power plant is struggling to operate profitably, and carbon dioxide still is vented into the air.
“The current technical situation at the plant is not so good,” Gao said. “The cost (of operating) is rather high. They have to solve this problem.”
China’s fossil-fuel based industries are another huge source of China’s carbon emissions.
In the process of producing chemicals, gas and other products, these industries often must isolate carbon dioxide in relatively pure form. This makes the carbon far easier to grab than the more-diluted streams spewed by power plants.
Carbon-capture proponents are hoping to match industrial plants that produce concentrated streams of CO2 with oil companies that can use them too boost production of aging fields.
There are successful models for such ventures.
In North Dakota, a coal plant separates out carbon dioxide in the process of producing methane gas. The Dakota Gasification Company has been piping about half of the captured carbon emissions to Canada, where it is injected into oil fields.
But there’s no carbon capture included in similar coal-to-gas plants now coming on line in China.
Gao, in a 2012 study
he co-authored, suggested initial development focus on four large industrial plants in Shaanxi province that now capture carbon and release it into the atmosphere.
But none of these projects are under way.
“It is a pity,” Gao said.
Hal Bernton: 206-464-2581 or email@example.com