A lot of people who push carbon capture and sequestration (CCS) as a way of reducing greenhouse gases from coal-fired power generation neglect to consider the reason coal-fired GHGs are a problem in the first place. They are a problem because they are huge. In the U.S., half the electricity comes from coal. This translates into two billion metric tons of GHGs every year. Coal achieved its dominant position in the U.S. because it is plentiful, easy to get, and therefore cheap. Capturing and storing the GHGs will be expensive. If it makes coal generation more expensive than natural gas–fired or nuclear generation, and it probably will, coal-fired utilities will switch to gas or nuclear or go bankrupt.
That’s why CCS is what I would call fake PR: it doesn’t take a mathematical genius to crunch the easy arithmetic and see it is not viable today and never will be. (For another example of fake PR, click here.)
But that doesn’t mean that all the government money being spent on it is wasted money. Far from it. The biggest part of the cost of CCS is capturing the CO2, and that is where most government-funded R&D is focused. The problem is what the R&D envisions will happen to the CO2. It will be “sequestered”: pumped underground. And there’s the problem. Pumping the stuff underground for permanent disposal ensures that the capture cost stays a cost. That is what presents coal-based utilities faced with carbon-abatement legislation or regulation with the stark choice of switching generation technologies or implementing CCS and going bankrupt. Is there no other use for all that CO2?
Of course there is. As I have pointed out in other posts, CO2 can be turned into carbon monoxide (CO). Mix CO with hydrogen and feed the mixture through a Fischer-Tropsch (FT) reactor, and you get liquid hydrocarbon fuels like gasoline and diesel. This isn’t some futurist fantasy: one-third of South Africa’s gasoline today is made at the Sasol FT plants in Secunda and Sasolburg. In June 2009, the American Society for Testing and Materials (ASTM) approved an international standard for FT aviation fuel. FT is here, and it’s big time.
To be able to use captured coal-fired power plant exhaust as a raw material to make FT fuels, you would need huge amounts of hydrogen gas. You need hydrogen to turn the CO2 into CO; and you need yet more hydrogen to mix with the CO to feed to the FT reactor.
We should remember though that any “hydrogen economy” scheme also presupposes the availability of hydrogen on an unprecedented scale. So the scheme I am proposing, which we could call CCR (where the “R” stands for Recycle), has the same obstacle as every other scenario that envisions hydrogen playing the central role in future transportation.
It is usually at about this point that people point out to me that this doesn’t sound much like a solution to the original problem, which is CO2 belching out of coal-fired power plants into the atmosphere. So I capture the CO2 and turn it into gasoline. What happens then? It is burned in a car, thereby producing the desired motive power—and undesired CO2, which also belches into the very same atmosphere. How is that a solution?
It is a solution in that it doesn’t put new CO2 into the atmosphere. CCR involves two broad GHG-emitting sectors, or areas of activity: (1) electric power generation, and (2) automobile transportation. Look at how carbon migrates into the air today from these two activities. Carbon in the form of coal is burned in a power plant, and carbon in the form of petroleum is refined into gasoline and burned in a car engine. Under CCR, the petroleum component would be eliminated. Yes, cars still burn gasoline, and that gasoline turns into CO2 during combustion. But that gasoline is made from recycled carbon. Every litre of CCR gasoline would offset the GHGs emitted by a litre of conventional gasoline. This would result in huge, absolute (not relative) GHG reductions.
Of course, the process that turns captured CO2 into gasoline is itself very energy intensive. In particular, turning CO2 into CO requires high-temperature heat. But if this heat were produced in a way that does not involve combustion, the overall process would produce little if any CO2. (Those who follow this blog know where I am going.)
What kind of energy can produce zero-carbon heat on a large scale? Nuclear energy, of course.
All of which is to say, nuclear energy is what would make carbon capture viable.
I once acted as a strategic adviser to a union that is active in the power generation sector. The union has members that work in both coal and nuclear plants. We struggled to find a way to economically address the environmental problems of coal. Our solution was to advocate shifting the baseload capacity mix toward nuclear, without eliminating coal-fired capacity. We were able to prove, using historical generator output, that this would result in major GHG reductions from coal. We proved that nuclear and coal generation are actually symbiotic.
Interesting that CCR presents another example of this symbiosis. Interesting also that the atom will be the decisive factor in turning CCS, which is fake PR, into CCR, which is viable.
Fuel made from CO + H +heat would offset its own emissions, once burned. So it would be carbon neutral (sort of like idealized fuel made from plants). It wouldn’t be offsetting anything more (for that would require removal of CO2 at some point in the process).
crf, thanks for bringing up the issue of the actual emission reductions inherent in making fuel from recycled carbon. I believe that if it could be demonstrated that it were replacing petroleum-based fuel, then it would be offsetting those emissions—thereby producing an absolute reduction in overall emissions.
And I believe that its very use would suffice to demonstrate that it is offsetting the use of petroleum fuel.
The only question would be an accounting one. Which sector’s emissions is its use reducing, electric power generation or light-duty vehicle transportation?
Actually, one artificial CCS scheme that has demonstrated large amounts of permanent CO2 capture at very low cost has done it not underground, but at the surface.
The minerals of whose mining that was a side effect are not the only ones that might be sought in order for CCS to be the main effect; lands made of peridotite are a better candidate. Look up the work of Dr. R.D. Schuiling on this.
Nuclear gasoline is a good idea, better than petroleum-derived gasoline, but not, I think, as good as nuclear boron.
— G.R.L. Cowan (‘How fire can be domesticated’)
GRL, that UBC/NRCan study looks interesting, and when I get some time I’ll look up Dr. Schuiling; thanks. Your nuclear boron comment is intriguing, and I’ll give it a look also.
About CCS: there could well be much better ways to dispose of CO2 than underground sequestration. But as far as I can see, that does not change the basic economic consideration facing coal-based utilities. It still costs money to capture the stuff. If that cost drives up the price of coal-fired electricity to a point where it cannot compete with other large-scale sources, utilities will switch to nuclear or go broke. CCS will simply not be viable on a large scale.
Japan has shown that hydrogen can be efficiently generated using a high temperature thermo-chemical reaction with sulfuric acid and iodine as catalysts. High temp generation IV reactors should be a good energy source. Los Alamos National Lab has a paper on synthetic gasoline production with carbon dioxide coming from the atmosphere. They have some cost projects made in 2006. Carbon capture a may be a more efficient way of getting the carbon dioxide. It would be interesting to look at economics of the South African experience of syngas production.
John, thanks for your comment. According to André Steynberg, who co-edited the book Fischer-Tropsch Technology (and who I believe works for Sasol), 75 percent of the capital and operating costs of conventional FT are in syngas production. As you probably know, they make most of their syngas by gasifying coal. In operations where natural gas is the feedstock, they steam-reform it.
Ken FabosNovember 22, 2010 Does anyone rlleay believe society will calmly stand by as we head towards 3b0C, then 4b0C, staring economic and social collapse in the face while we focus on cheap energy as some kind of overriding objective? Going on performance to date, yes.Two full decades of anthropogenic climate change being established science and Australia’s policy focus is fully on maximum expansion of coal and gas extraction and export with some ineffectual climate policies’ to distract and pacify public concerns. Expansion of grid supply by construction of big new coal fired power plants such as in the Hunter Valley and near Lithgow are going ahead and look to me to be intended to prevent the issue of decarbonising our energy supply getting mixed up with the issue of maintaining growth and reliability of supply; we’ll have enough fossil fuel generating capacity that building low emissions capacity will remain optional’ and can be deferred another decade or two. Pressed hard enough by concerned voters leaking to the Greens there might be a switch of emphasis from the LibNatLab middle to push for gas over coal despite gas being unable to deliver the long term emissions reductions needed. Screw the future, Australian’s don’t want their power bills going up and LibNatLab policy makers are sure of it.