Several people, knowing my background in Chemistry and Energy, have asked me what I think of 'clean coal' power stations.
My usual reply is - 'coal fired power stations are fine, as long as sulphur dioxide and nitrogen dioxide emissions are kept to a minimum'.
These are toxic gases, and some of you will remember the amount of pollution which used to be caused by burning raw coal. Smogs and blackened buildings were the result, and acid rain.
But one guy said to me 'no - I didn't mean that. What do you think about Carbon Capture? Clean Coal.
I was surprised he'd heard of it; he was quite young, and it's unusual to meet a young person well-informed about (and interested in) Energy.
Anyway, I replied along the lines given below. So here goes ......
"Clean Coal" is a political term. It doesn't mean 'clean' at all.
It's what 'green' politicians say when they mean Carbon Capture and Storage (CCS), or Carbon Sequestration.
If there was ever a technology which deserved to be labelled Lunatic Fringe, this is it.
We’re told that there’s a problem with releasing CO2 into the atmosphere.
Let's think about a power station burning coal.
One large new power station, say 2000MW capacity, burning about 4.5 million tons of coal a year.
This will produce about 13 million tons of carbon dioxide annually, which, if you do the sums, comes to about 20 tons per minute.
The Carbon Capture process, according to current information, will use about 40% of the power produced by the plant.
The carbon dioxide, a gas, must be collected from the high stack, separated from other gases, liquefied, (very low temperature needed) and then pumped somewhere to a hole in the ground. Such holes are very rare; you can only do it in areas where the geology is exactly right.
To do it they need, therefore, perhaps hundreds of miles of pipelines, with pumping stations and cooling stations all the way along the pipe.
At the hole in the ground, they need a huge pump to push the CO2 down, where it needs to be kept, forever, without leaking. If it leaks out, the whole exercise is futile. They really need an infinitely large leakproof container.
Unfortunately, when liquid CO2 sinks to depths where the surrounding ground is hotter than minus 78C, it turns back into a gas, expanding considerably.......
Assuming that a way can be found to keep the CO2 below its boiling point ....
The gas has to be pumped down the hole at the same rate at which it is being emitted from the plant... 13 million tons a year, 20 tons a minute.
The plant has an expected life span of 50 years, so now the hole in the ground has to contain 650 million tons of CO2.
This is just for one plant.
For any more plants, find more holes.
If the hole fills, then find more holes.
Then construct more pipelines, pumps, cooling stations, etc.
Now perhaps you will have some inkling of the scale of the problem.
A number of tiny CCS enterprises associated with gas fields are already working, and the costs, unsurprisingly, are much higher than planned. Those interested in the costs can google "carbon capture Norway".
Our own Government sinks millions into carbon capture, mainly on discussion committees and government-funded studies.
In spite of its unfeasibility, those in charge of our energy policy still say that carbon capture must be built into all new UK coal fired power stations.
I don't know the cost, and nor does anyone else, since it's never been done before on the required scale - but when a project is entirely new, taking the anticipated cost and multiplying by 10 often gives a fair approximation.
UK government policy is: no new coal stations without carbon capture.
Think of the reduction in efficiency (40%) of the power stations themselves, which means another 40% on the price of any electricity produced - and that's not including all those pipelines, pumping stations, cooling stations and almost certainly subsidies.
Then there's the question of leaks. If we ever get to the stage of pumping hundreds of millions of tons of liquid CO2 into the ground, how are we going to ensure that it stays there?
Lastly ... think of the enormous subsidies which will be made available for this unworkable technology. Climate-change energy schemes attract subsidies like hedgehogs attracts fleas.
In cynical moments I sometimes imagine that the more unrealistic the scheme, the larger the subsidy. However there is a bigger picture here.
When it comes to energy, decisions are not usually based on the science or the economics, but the politics.
Making 'carbon capture' a requirement is an effective way of stopping a country producing electricity from coal.
If the price spirals out of control, no private company can contemplate the building of coal-fired power stations.
Perhaps this is the intention.
I am indepted to a blogger, "Tony from Oz", for his blog entry on carbon capture, which stuck in my mind. Tony, I do not know how to contact you, but I hope you do not mind my use of your phraseology in parts of this article.
....Note for students ..... please remember that this article is my personal view. Do not take my word for any of it. Learn some Physics and Chemistry; do your own research and come to your own conclusions .......
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