Now that the debates triggered by the IPCC report seem to have cooled down a little, the conclusions are pretty much final. Climate change is happening, temperatures are rising, natural disasters are intensifying, and despite all efforts, carbon emissions are still skyrocketing (literally).
Scientists are rushing into developing techniques to handle at least one of the above. Such proposal came from a team of Scandinavian researchers, who presented a cost-cutting way to capture and store carbon. The method implies that emissions should simply be refrigerated at the source, and turned into liquid, which can then be easily transportable.
As part of the discussions, IPCC considered all possible options and reassessed all geoengineering techniques that could help the world reach the needed targets. The experts agreed that most of these would only help in a short run, but considering the urgency of the matter, immediate action should be taken. Carbon capture and storage (CCS) was selected as the most suitable and probably the only proven mean to reduce the concentrations of the greenhouse gas in the atmosphere. Although many still question where the once captured carbon would be stored, and worry about cost of transport and possible leaks, CCS still won over all other options.
The work of a scientific team from Sintef, a Scandinavian research organization, addresses these issues, and proposes a neat way to deal with them. Petter Nekså, the lead scientists, and his co-workers, showed that refrigerating emissions, at the power stations, condenses the gases into liquid, while using a lot less energy than any other carbon extraction technique. In addition, in this form, carbon can be transported much easier and a lot cheaper via existing pipelines, and in tanks to the chosen locations.
The team also proposed a solution to the problem of storage. They suggest that if CO2 is turned into a liquid, it could be easily stored under the North Sea, in the region known as Sleipner field. This area is known for its capacity to hold as much as 50 years worth of emissions from 20 coal-fired plants, and this will occupy only 1% of the available pore space. The scientists handle the safety issue, by basing their proposal on the numerous seismic surveys that have been conducted in the area. These show that CO2 will remain securely in the shale, and the risk of leakage and ocean acidification is minimal.
Does this sound like a solution to atmospheric pollution? I guess we should leave it to the experts to say, hopefully they know better.
Image (c) Shutterstock
When
the Feed CO2 concentration is sufficiently high (eg > 60%), pursuant to the
so-called Inverse Lever Rule CO2 can indeed be captured via refrigeration with
a very low energy and capital cost. In fact, in the Permian Basin area
of West Texas, for more than thirty years CO2 has been separated by
refrigeration from natural gas produced in the context of longstanding Enhanced
Oil Recovery programs. The largest of these refrigeration plants separates more
than five million tons of CO2 each year. This is therefore a fully-proven
process which importantly has a high tolerance of SO2 – an important
consideration for CO2 capture for a coal-fired power plant. By comparison, the
amine capture process currently favored for CCS has only rarely exceeded 1.5
million tons/year of capacity at a single plant, and has a tolerance of SO2 of
just a few ppm – a level that has never been scrubbed to by any known
commercial process on a sustained basis (for a short duration pilot test the
amine solution can of course be repeatedly replaced, which is very expensive
and creates an awkward environmental disposal problem).
Quite separately, in the Permian Basin gas
separation membranes have also been used for more than thirty years to increase
the CO2 concentration. The largest of these plants processes more than ten
million tons of CO2 each year, so this is another fully proven process (which
again has a high tolerance of SO2).
Moreover, in more than one plant gas
separation membranes and refrigeration are used together at the same location in
an optimal way. It therefore seems that the Gas Processors are very far ahead
of the people in Brussels who provide funding.
I have been studying these plants (and many
others of direct relevance to CCS and beneficial CO2 use) in detail for more
than seven years now. Their performance is impressive, and it is quite
surprising they have not been embraced for CCS.
If you would like to learn more about these
plants and their implications for low cost CO2 capture and beneficial use,
please find me via LinkedIn: David Willson, Stanbridge Capital.