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The notion of Carbon Sequestration / Carbon Capture and Storage / CCS seems to be appearing in the news. I shouldn't need to write about it, but it now appears I am going to have to mention a few things which should be so obvious they should not need mentioning!
What is Carbon Sequestration? What is Carbon Capture and Storage?
The idea is that as there's an ecological problem with CO2 and the amount of burning off of fossil fuels and the global warming and various doom-laden scenarios about it, it would be possible to reverse this by capturing some of the CO2 that's in the air and hiding it away so it doesn't do any harm.
I have even heard it suggested that when crude oil is pumped out of an oil well, the space left down there is then filled up with carbon dioxide which has been extracted from the atmosphere.
Now let's examine this logically. Suppose you have a car and a can full of fuel and you do an experiment. Empty the fuel into the car fuel tank. Turn on the engine. Now, leave it running. How long will it run? Meanwhile, take the empty fuel can and try to fill it up with the gas that's coming out of the exhaust pipe. Now, do you think you are going to get all the CO2 that's coming out of the exhaust pipe during the burning of that fuel back into the can? It's a bit like trying to get a genie back into a bottle, isn't it?!
Apply the same idea to a million cars, and is it going to be any less difficult to get the exhaust gases back into a million empty fuel cans? No, it's going to be exactly the same proportion of problem. A million times as much fuel, and a million times as much exhaust, so the same level of difficulty.
An oil well is pumped out using pressurised water, but even if you could somehow get the water out, there is plainly not going to be enough space to get much CO2 into, at least not in relative terms to the amount of crude oil that has come out of the hole.
Right, well let's make the CO2 into dry ice. That should help, shouldn't it? But wait. I've seen dry ice, and do you know what it does after a while? It changes back into CO2 gas. It does this quite quickly. Trying to reduce the amount of carbon dioxide in the atmosphere by burying dry ice (solid CO2) is like trying to reduce sea levels by burying ice (solid H20)! Obviously nonsense.
It's important to understand these concepts because it seems that politicians are trying to fool people into believing things. Some of the politicians involved, if they were in the cleaning business, I'd imagine they would sweep all the muck under the carpet and hope you didn't notice.
Incidentally, there ARE ways of carbon sequestration that work, but they have to make actual sense. Just believing it won't do. It has to actually work, and some of these things are quite difficult! For example, if you could encourage coral reefs to grow more, it could turn CO2 into calcium carbonate, which is solid chalk and doesn't take up so much room as CO2 gas. (1m2 of coral can produce 10g of calcium carbonate per day, representing 2.4 litres of CO2 gas removed from the atmosphere). That's pretty good.
Or, another way is to plant more trees (a lot more trees!) and they'll turn CO2 into wood. Even then, it would be hard to find enough ground to plant as many trees as would be required to compensate for all the trees that ever grew during all the ancient times when all those oil deposits were buried in the first place! Plus, the wood produced would need to be properly sequested, for example by making good quality solid wood furniture and keeping it indefinitely to become future antiques. Another good way of sequesting carbon is to grow trees and then turn the recycled pulp into books. Books are kept on an ongoing basis and are a source of wisdom.
Turning CO2 into carbonates, such as calcium carbonate, might work. (The White Cliffs of Dover are made of calcium carbonate). Effectively the CO2 is turned to stone, which can be stored indefinitely. In contrast, just hiding the CO2 as dry ice underground, is surely folly?! Even in old oil wells which have held natural gas for millions of years, there's going to come a time when the CO2 will escape. It might escape in 10 years, or 50 years, but it will escape.
The scientific fact is that for every twelve grammes of carbon which is burnt, it takes 32 grammes of oxygen from the air (which takes up 48 litres), and converts it into 50 grammes of carbon dioxide which has a volume of approximately 48 litres, or maybe slightly more. The distinction is that 12 grammes of carbon is just a small lump, but 48 litres of air is volumetrically as big as a small human. So, you can see why the space can't simply be re-filled.
Converting the CO2 back into carbon sounds good at first, but the problem there is that it would take at least as much energy as was made from burning it in the first place. Other methods which produce compounds (such as calcium carbonate) can be done by nature if given some encouragement, but this takes a long time. Industrial processes to convert the carbon dioxide to something else tend to be expensive, sometimes more expensive than the value of the fuel.
I like the idea of the coral reefs, but I have the impression that there is a time factor to be considered.
What's important with this sort of thing is to look at what independent scientists say, not what evidence the governments have made up for the sakes of appearance not fact, and to have a grasp on the scientific issues involved. So, for example, if politicians said "Let's tackle carbon dioxide ourselves! Let's get all the people to huff our CO2 breath into party balloons and fill up the Millennium Dome!", you have to be able to know that it's silly and isn't going to have done the world's ecosphere much good in a hundred years!
Maybe a better idea is to use other fuel instead which does not need to be sequested. (Naturally grown stuff's carbon comes from the present day atmosphere in the first place, so when you burn it, ashes to atmosphere, dust to dirt, what goes around comes around). Vegetable products can be turned into alcohol, which is like petrol/gasoline except that the government would prefer to control the market and not allow you to distill it just in case you decide to drink it and not pay the duty on it! Eco Diesel is another example of renewable fuel. No danger of it being guzzled at parties, although you might put it on your fish and chips. But again, some governments (the UK for example) have (2005) taxed it to make it more expensive than fossil fuel diesel. I wonder if they are trying to support a fossil fuel industry rather than moving forward to a renewable ecology. Maybe the western politicians are servants to the kings of Saudi Arabia.
Other stuff: Eco Notions //// Carbon //// Waterworld //// People don't vote for politicians //// Natural World //// Oil //// Save the Panda (but not the one at Google).