기술
The little understood process of carbon capture and utilization
Responding to a push from industry, the European Union seems to be set on exploring ways to recycle carbon dioxide, through a technique called carbon capture and utilization (CCU). However, most of us know little about this technology.
Carbon capture and utilization (CCU) is a viable, though poorly understood concept for reducing carbon emissions. Unlike carbon capture and storage (CCS), which treats CO2 as a waste product, the CCU process converts it into commercially viable products such as bio-oils, chemicals, fertilizers, and fuels.
In a report published by the Centre for Low Carbon Futures in 2011 and CO2Chem Publishing in 2012, the authors pointed out the considerable cost burdens associated with CCS, and this has already been proven to be true, as seen by the slow growth of CCS facilities worldwide.
Besides being a complicated technology, CCS also has other drawbacks, including being costly, the possibility of leakage, long-term liability issues, problems with public acceptance of onshore geological storage locations and limited cost-effective storage capacity in some essential regions.
Lawrence Livermore National Laboratory demonstrated coal gasification in large-scale field experiments at the Rocky Mountain Test Facility (above) near Hanna, Wyoming.
U.S. Department of Energy
Carbon capture and utilization in the European Union
CCU is already being used in some manufacturing processes - like the fizzy bubbles in soft drinks. The CO2 used to make carbonated drinks is sometimes captured from industrial processes. And in the Netherlands, CO2 from industries operating in the port of Rotterdam is transported to the nearby Westland area, where it is used in greenhouses to help stimulate the growth of vegetables.
EU Observer notes that CCU is gaining quite a bit of support, like Alan Knight, the general manager for corporate responsibility at steel giant ArcelorMittal. At the Companies vs Climate Change Conference in Brussels last month, Knight said he preferred CCU to CCS.
"Why store it? Why landfill carbon? I thought landfill was quite [at the] bottom of the waste hierarchy?" What Knight is talking about is the circular economy concept that says that putting waste in a landfill should be the final option after having tried reusing, repairing and recycling.
Penn State Researcher Chunshan Song sees carbon dioxide as a valuable ingredient for creating fuels, industrial chemicals and other materials.
Penn State
Calling CCU an "really interesting solution," Knight said it is better than paying someone to store CO2. "If we can turn CO2 into something we could sell, we would be incentivized to do it," said Knight.
The European Union is apparently going to increase its support for the development of CCU through a new Innovation Fund. It will be part of the Emissions Trading System (ETS) from 2021 onwards. The new fund is a successor to the NER300 fund, which was supposed to help set up CCS projects across Europe. That fund failed after member states didn't pay their part.
The NER300 fund was supposed to open to only CCS initiatives and "demonstration projects of innovative renewable energy technologies." But from the start, member states demanded that CCU also be included in the fund. So with the change being suggested in the new fund that would include both technologies, it is expected to pass when EU institutions will meet again on November 8.
Scientists warn that on current greenhouse gas emission trends, Earth is on track for twice the 2 C target -- a recipe for catastrophic droughts, storms, floods and rising seas
Simon Maina, AFP/File
"We are pretty sure, let's say 99.5 [percent], ... that CCS and CCU will be part of that Innovation Fund," EU commission official Mark van Stiphout said last Thursday, at a conference on CCS in Rotterdam. What is interesting about the wording on the inclusion of CCU in the fund is one section of text that states CCU projects eligible should be "environmentally safe" and contribute "substantially to mitigate climate change."
Will CCU help in mitigating climate change?
OK, stay with me. Remember that in CCS, carbon dioxide is removed from the industrial process and, to make it simple, stored underground. We have discussed the possible leakage of this greenhouse gas back into the atmosphere, so that is one concern with CCS.
However, with CCU, the process does not focus on extracting carbon dioxide from the atmosphere, but on providing chemical raw materials. This means fossil fuel-fired power plants with CCU technology supply CO2 as a raw material for other industrial or manufacturing operations where it is temporarily bonded.
The Peterhead Carbon Capture and Storage (CCS) project in Aberdeenshire, UK.
Penn Energy
The key phrase is "temporarily bonded." This means the bound carbon is released again after the use of the CO2 derived raw materials. So while CCU will not mitigate climate change, per se, it is useful in the circular economy. However, if innovation can help in developing a way to permanently protect CO2 from being released, the process can play an important role in protecting the climate.
Needless to say, the debate over CCU versus CCS is still going on, even while Germany and the U.S. have invested substantially in the technology. CCU can contribute to a green economy and this is why it is necessary to consider funding technology and development in CCU.
Digital Journal
2017.11.02
